L18 8.1L swap resource thread

[Larry]

I am active on 3 main forums (67-72chevytrucks, Expedition Portal, and CK5) and on average I get 3 to 5 PM’s and emails each week related to 8.1L swap questions from people all over world into every imaginable vehicle. While it is fun to answer each and every PM, it eats up a lot of time. Since don’t have time to write a book and make a profit on it I am hoping to make this thread the main resource thread to steer people to in the future .

The following information is a cumulation of information from GM Powertrain Application Manuals, Technical Data Sheets and GM Service Manuals

L18 8.1L vehicle applications:

2000-2011 Workhorse Custom Chassis
Transmissions: 4L80E, Allison 1000, Allison 2200

2001-2002 GMT400 3500-HD trucks (these were the 1988-2000 body style chassis cab trucks with leaf sprung I-beam front axles. All left GM as 2wd but many were converted to 4x4 in the aftermarket).
Transmission options: NV4500 & 4L80E

2001 – 2002 Chevrolet Express/GMC Savanna (G-Van)
Transmission option: 4L80E

2001-2006 GMT800 2500HD/3500 (& 2007 GMT800 Classic)
Transmission option: Allison 1000, ZF S6-650 6 speed manual

2001-2006 Suburban/Yukon XL/Avalanche 2500
Transmission option: 4L80E

2001-2009 GM Medium Duty trucks
Transmission option: Allison 1000, Allison 2200, ZF S6-650 6 speed manual, Eaton 5 speed manual

GM Powertrain also sold the L18’s to various Marine engine manufacturers where they marketed it under their own names. The two main users were VolvoPenta and Mercruiser. Both had a few different versions of the L18 with different HP ratings.

L18 HP and torque ranges depending application: 340HP/455 LB. FT to 420HP/505 LB. FT (Marine)

L18 GVWR Ranges: 8,600 lbs. to 44,000 lbs (Medium Duty & RV)

PSI is building a Gen VII Big Block based on the 8.1L if you will. The new big hoss is an 8.8L version initially being fueled by propane for on-road vehicles. Navistar's IC Bus (School Buses) will be the first on-road vehicle to use the new 8.8L, which are launching in Q4 2015. The 8.8L has already been in production for a few years as a stationary engine for well pumps, gen sets, etc. I've seen the 8.8L and had the opportunity to tear one down to little bite size pieces. The 8.8L is a BEAST! It's hard to believe the 8.1L could have been improved upon so greatly. More details on that engine in the future.

Notable items:

- The L18 8.1L is 496 cubic inches, not 502. The marketing name was Vortec 8100, not Vortex.

- 2001-2003 L18’s use a return type fuel system. This means there are two fuel lines at the fuel rail. One supply and one return. There is an adjustable fuel pressure regulator on the fuel rail return side.

- 2004-2010 Silverado, Sierra, G-Van and Workhorse L18’s moved to a returnless fuel system. The purpose of moving to a returnless system was done for the purpose of reducing evaporative emissions by eliminating hot fuel being returned to the fuel tank. The fuel pressure regulator looking thing on the fuel rail is actually a fuel damper. Fuel pressure is regulated by a non-adjustable regulator in the fuel module assembly located in the fuel tank. Marine went returnless in 2005 while medium duty went returnless in 2006. 2004 also brought a new design intake gasket set and change in intake bolt lengths to address oil and coolant consumption.

- 2003 brought a new design throttle body with a much smaller motor. This seemed to help address the touchy throttle on previous years. The harness connector and TAC modules are different between the early electronic throttle body and later. Make sure you know what you have before ordering a harness.

- 2003 also brought new bare aluminum valve covers

- 2004 brought new designs with the Cam and Crank sensors to improve durability. The later designs work great! Prior sensors, especially the crank sensor, are extremely prone to premature failure. There seems to be a lot of mystery around the Cam sensor (CKP) availability. Some say the 2001 - 2003 sensors is discontinued but GM shows it’s actually the 2002/2003 sensor that is discontinued. 2001 sensors seem to be readily available from GM/AC Delco meanwhile all three sensors appear to be readily available by Standard Motor Products. RayLar has a great write up on the cam sensors with their respective timing chain covers and timing chain sprocket. The only inaccuracy is their year cut-offs don’t jive with what the parts catalogs indicate.

2001: AC Delco 213-1063 or Standard Motor Products PC948

2002/2003 Discontinued through GM & AC Delco although it shows available through Standard Motor Products PC949

2004-2010 213-3826 or Standard Motor Products PC620

- EGR was also eliminated with the 2004 model year

- In the GMT800 truck application, the L18 makes 355 LB. FT. of torque at 800 RPM with a peak torque of 455 LB. FT. at 3,200 RPM. That is over 300 LB. FT. of torque at idle! Not many stock gasoline engines can claim that much twist at idle.

- The L18 is one of the only engines to pass the "Marine Dock'' test, in which it is run at full throttle for 300 consecutive hours, and a minimum of 1000 hours at full-throttle operation for truck applications. Not many engines carry this accolade. The Ford V10 has not passed this test and there is no documentation where the Gen III "LS" engines have met this accolade either.

- All L18 engines from 2000 to 2011 ran on the Delphi P59 ECM, while the later small block LS engines moved onto E38 and E78 modules.

GM Service Bulletins related to L18 engines:

01-06-01-018: Engine Tick Noise at Valve Train Speed/Loss of Power (Replace Push Rod): June 2001

02-06-01-035 High Oil Consumption: October 2002

PI01586A 8.1L Changes in Heads Bolts and Gasket for 2004.5 Engines: December 2003

04-06-01-018 Information on Revised Design of Intake Gasket and Related Bolts for 2004 Mid-Year Enhancement: June 2004

PIP3193B Excessive Oil Consumption: July 2005

06083: Product Safety - Crankshaft Position Sensor Engine Stall: December 2007

Engine Type V8

• Regular Production Option (RPO) L18

• Displacement 8.1 Liter 496 CID

• Bore 107.950mm 4.250in

• Stroke 111.00mm 4.370in

• Compression Ratio 9.1:1

• Firing Order 1-8-7-2-6-5-4-3

Lubrication System

· Oil Filter Type PF454 or PF1218

· Oil Type 5W-30

Oil Capacity

• With Filter Change 6.1 Liters 6.5 Quarts

• Without Filter Change 5.7 Liters 6.0 Quarts

Oil Pressure - Hot

• Minimum 34 kPa @ 1,000RPM 5 psi @ 1,000RPM

• Minimum 69 kPa @ 2,000RPM 10 psi @ 2,000RPM




Part Numbers used for MY swap: Keep in mind, my part numbers are for use with an early 8.1L, manual transmission, mechanical throttle body and return type fuel system along with the G-van/Workhorse/Medium duty accessory brackets. Some of these part numbers such as the cam sensor may not be the same for you if you are using a newer engine. Do some research. RayLar has a great write up on the different cam sensors and cam gears.

Part Number Description
52445253 A/C compressor
11516360 A/C compressor bolts
12581203 Belt tensioner
11516367 Belt tensioner bolt
12578330 Coolant Crossover
12571593 Coolant Crossover gasket
12575172 Crank Sensor
12575123 Dipstick
12570590 Dipstick tube
12559976 EGR Cover
12580673 EGR Cover gasket
12574560 Engine Cover
12567370 Engine Cover Ball Stud
12562957 Engine Cover Bracket
12562958 Engine Cover Bracket Stud
12582964 Flywheel
12563485 Flywheel bolts
EP381 Fuel pump
W0000393 HOUSING ASM - PCM
12580771 Idler on alternator bracket
213-298 Knock sensor - Drivers side (this sensor requires being moved to a different hole in the block)
213-2829 Knock sensor - Passenger
12573337 Oil Cap
12581140 Oil Fill Tube
11518950 Oil fill tube stud
12568356 Oil pump drive
12575055 RAIL KIT,M/PORT F/INJN FUEL
17096144 Throttle body (1998 L29 7.4L)
12570168 Throttle body gasket
1000LS1U Throttle cable
20416 Upper rad hose (Gates)
When swapping one of these engines into a 67-72 or 73-87 (91 square body) truck, the ORD HD engine crossmember works perfectly to address oil pan clearance. Taking a torch to the stock crossmember is just hacky…buy a nice ORD piece. Don't be a hack

Swap info:

- The L18 8.1L has the same foot print as older BBC engines and will bolt in the same as any other older SBC and BBC. In fact, the L18 will accept any exhaust manifold or header from older BBC engines. The starter motor from any older SBC and BBC for use with a 168 tooth flywheel will also fit the L18. Any transmission from an old PowerGlide, TH350, TH400 to Allison, to NV4500, etc. will bolt on to it as well.

- It is not required to run electronic throttle control on these engines. If you choose to keep it simple and reliable like I did, you can use a 1996-2000 L29 7.4L cable operated throttle body on the 8.1L. Cruise control could be adapted to mechanical TB buy using the cruise control controller from a L29 as well. An aftermarket TB spacer is required to be able to use the L29 TB in order to allow room for the arm to swing.

- These engines love higher than spec fuel pressure. Crank it up to about 67-68 psi and watch it come alive! (The adjustable fuel pressure regulator makes the early 2001-2003 fuel rails more desirable).

- There are several accessory bracket designs used on these engines. In my experience, the G-van/Workhorse/GM Medium Duty accessory brackets are ideal for swapping into a vehicle with A/C as the A/C compressor is located up high on the driver’s side whereas the Silverado/Sierra brackets position the A/C compressor down low on the passenger’s side which causes a major frame clearance issue during swapping. To convert a pickup truck L18 to the the high mount compressor design the water pump, crank pulley/balancer must be replaced as well. Don’t be that guy to hack up a frame to make room for the A/C compressor! If not running A/C, the Silverado/Sierra brackets will work fine. More information on that below.

Wiring: Like any late model engine swap, there are many different avenues for wring these engines. I personally do not like going the route of reworked donor truck harnesses. There is just too much that needs to be removed from a donor harness to bring it down to a manageable/clean size and the margin of error while rewiring it is just too great. In my opinion the only way to go is start with a fresh stand- alone harness from Howell Engine Development or one of the many other good harness suppliers out there.

Identification Photo’s:

This is the most commonly found accessory bracket design, as it is the Silverado/Sierra setup. The location of the A/C compressor causes frame interference when swapping into an older truck. If installing into a non-A/C vehicle these brackets are great. Just remove this compressor and eliminate the belt.

This setup moves the compressor to high towards the driver's side like older engines. This setup is found on G-van's, Workhorse and GM Medium duty. The power steering pump in this picture is a ZF, not the typical Saginaw type pump although a Saginaw pump will fit this type bracket. If you would like to order any of the pieces for this set up use VIN 3GBKC34G61M101958 for part number look up.

Same as above but with the heavy duty industrial/marine oil pan

Same brackets as above but with A/C delete

Now, if you want to get real crazy with onboard air this high GVWR range Medium Duty truck with air brakes set up is for you. This set up still allows for the clutch fan to be water pump mounted in addition to the option in this picture.

 

[COCHEV]

BOOM! awesome man! Who wouldn't want one of these after reading that...

 

[Larry]

BOOM! awesome man! Who wouldn't want one of these after reading that...

Heck yea!

Next up are the new model year summaries that GM Powertrain publishes every year. These started in 2003 so there isn’t one for the 2001 and 2002 engines. I have the Summary pages from 2003 to 2009. 2010 and 2011 engines were the same as 2007 -2009 therefore no Summaries were written. These summaries are public and can be found on GM Powertrain’s website along with information on the smaller LS engines. That said, this information is not proprietary with no harm with reposting it here.

2003 Model Year Summary

• Application in Chevrolet Kodiak and GMC TopKick (medium-duty trucks)
• Chevrolet Express and GMC Savana Application Eliminated
• Powertrain Control Module and Software with Additional Monitoring Functions
• Improved Denso O2 Sensors
• Solid-State Oil Pressure Sensor
• Revised Electronic Throttle Body
• Coolant Path to Heater Core Revised on Chevrolet Silverado and GMC Sierra
• Revised Catalytic Converters
• Revised Oil Fill Tube and Cap
• Revised Oil Level Indicator
• Sight Shield Revised for Chevrolet Silverado, Suburban and Avalanche and GMC Sierra and Yukon XL
• Starter for Chevrolet Silverado, Suburban, Avalanche and GMC Sierra and Yukon XL
• Exhaust Valves Revised on Marine Variant

FULL DESCRIPTIONS OF NEW OR CHANGED FEATURES:


APPLICATION IN CHEVROLET KODIAK AND GMC TOPKICK

The Vortec 8100 8.1L V8 (L18) is now offered in the Kodiak and TopKick, or commercial duty Family II and Family III trucks. These chassis-cabs provide the foundation for a host of vehicles from delivery vans to small dump trucks. The Vortec 8100 will be available with three gross vehicle weight ratings (GVWR): 16,000, 18,000 and 19,500 lbs. The Kodiak and TopKick replace 3500 HD and medium-duty chassis cabs. The 8.1L was launched in Kodiaks and TopKicks built from early calendar 2002 as 2003 models.

Depending on how the vehicle is ultimately finished, Family II and Family III trucks can generate far greater electrical demands than the typical truck. For these applications, the 8.1L can be equipped with two 105-amp alternators rather than a single 140-amp alternator (the second alternator is mounted on the right side of the engine). The accessory drive belt is therefore longer in these applications.

CHEVROLET EXPRESS AND GMC SAVANA APPLICATION ELIMINATED

The Vortec 8100 is no longer an option in the Express and Savana. The Vortec 6000 6.0L (LQ4) will be the most powerful engine offered in the redesigned 2003 models (see Product Specifications).

POWERTRAIN CONTROL MODULE AND SOFTWARE WITH ADDITIONAL MONITORING FUNCTIONS

A new Powertrain Control Module (PCM), called P59, manages the 8.1L. With this new PCM, processor clock speed increases from 21 to 24 mHz and memory capacity doubles to 1.1 megabytes. The PCM also manages the 4.3L V6 (LU3) and all gasoline-powered Vortec V8 truck engines, and provides one of the most sophisticated engine control systems in the industry.

Commonality offers the advantage of reducing inventory complexity and increasing efficiency at various assembly plants. More important, P59 offers the most precise engine management possible, optimizing performance according to temperature or operating conditions and virtually eliminating unintended variation in every function it controls, from ignition timing to fuel delivery to transmission shift points. It also allows GM Powertrain engineers to monitor more engine operations and improves the accuracy and robustness of the OBDII (On-Board Diagnostics) system.

For example, the PCM now measures electrical current flowing to the oxygen or 02 sensors (crucial components of the emissions-control system) on vehicles equipped with the Vortec 8100. Previously, the O2 sensors were monitored with a time-to-activity algorithm, which required more measurement latitude to ensure proper operation. The new PCM more quickly reports a malfunction in an O2 sensor with virtually no margin for misreporting. It also allows a new Engine Off Natural Vacuum (EONV) diagnostic for the Onboard Refueling Vapor Recovery system (ORVR), which reduces evaporative emissions by preventing gasoline vapor from escaping the vehicle into the atmosphere. With EONV, the PCM continues to operate when the engine is turned off, monitoring pressure in the fuel tank and ORVR system. If pressure bleeds off more quickly than ambient temperature and other conditions indicate, the PCM can determine whether the system has a leak, even when the vehicle is parked. The new PCM ensures that the engine operates according government emissions regulations. And thanks to its precision, it will also reduce the number of false alarms— OBDII “service engine” warning lights—that require dealer intervention.

The new PCM is roughly the same size as the PCM it replaces and is installed in the same place as the previous PCM in various applications—in all applications on the firewall or inner fender, depending on the vehicle. There is no visible difference in the engine bay.

IMPROVED DENSO OXYGEN (O2) SENSORS

The Vortec 8100 has new oxygen (O2) sensors. These O2 sensors have the same 6.6-volt heat rating as the parts they replace, allowing them to achieve closed loop operation—and maximum exhaust emissions reduction--in minimum time. The new sensors allowed engineers to implement the current monitoring function provided by the new PCM, and they are common to other truck gasoline V8s.


SOLID STATE OIL-PRESSURE SENSOR

The 8.1L now has a fully electronic, solid-state oil pressure sensor, replacing an analog/mechanical sensor. The solid-state sensor is installed in the same location in the engine block, but it has no mechanical parts, increasing reliability. Its introduction coincides with a new electronic instrument package in some applications.

REVISED ELECTRONIC THROTTLE BODY

The Electronic Throttle Control (ETC) system on the 8.1L uses a new throttle body and Throttle Actuator Control (TAC) module. The throttle body’s diameter (75 millimeter) has not changed, but the new part features a ``wrap around’’ throttle motor. The electric motor that operates the throttle plate is literally built around the throttle body and responds more quickly to commands from the TAC. The new throttle body is now common to all gasoline-powered GM truck V8s.

Before the Vortec 8100, ETC was largely reserved for premium passenger car engines and some heavy duty trucks. There is no mechanical link between the accelerator pedal and the throttle. Besides throttle pedal angle, the PCM measures other data, including the transmission's shift points, in determining how far to open the throttle. ETC delivers outstanding throttle response and can be calibrated to match demands in different applications.

COOLANT FLOW FROM HEATER CORE REVISED ON SILVERADO AND SIERRA

In the 8.1L applications, the flow pattern for engine coolant has been revised to heat the cab more quickly during cold temperature operation.

The heater core is a small radiator inside the vehicle’s instrument panel, behind the engine firewall. Hot coolant from the engine flows through the heater core, where the ventilation fan forces heat through ductwork to the dash vents and into the cab. In extremely cold temperatures, large displacement engines such as the 8.1L can take some time to reach a temperature sufficient to heat the cab. GM engineers have developed a simple, effective method to increase customer comfort by shortening the time it takes to heat the cab.

On Silverados and Sierras, the heater return hose is now routed into the radiator return hose rather than the radiator itself. That means the coolant flowing in and out of the heater core bypasses the radiator, where coolant is at its coldest temperature anywhere in the cooling system. Coolant flowing to the heater core stays out of the radiator until the engine reaches full operating temperature and the thermostat opens. This allows the cab to heat more quickly, meeting GM’s stringent time standard, without reducing cooling capacity during high-temperature operation.

CATALYTIC CONVERTER REVISED

The mix of precious metals in the 8.1L catalytic converter has been revised for all applications to meet more stringent 2003 exhaust emissions standards. The new converter has the same volume as the one it replaces, with similar architecture. The difference lies in the combination of platinum, palladium, rhodium and other rare metals in the converter substrate, or core. These metals create the chemical reaction that turns the majority of exhaust emissions into oxygen and water vapor. The combination has been optimized to achieve emission standards with more of the common varieties of these metals and less of the rarest types. This process limits environmental impact and keeps cost to the customer as low as possible.

REVISED OIL FILL TUBE AND CAP

The oil fill tube on 8.1Ls built for Silverado and Sierra has been revised to accommodate the new throttle body. The tube is angled more sharply as it rises from the engine block. It is also manufactured from molded plastic rather than steel, and sealed with an O-ring rather then a press-fit seal (the fill tube on L18s built for Workhorse Custom Chassis is still made of steel). Finally, the fill tube on all 8.1Ls except those built for the Chevrolet Kodiak and GMC TopKick, have a new corporate cap with a global symbol rather than the word ``oil.’’

REVISED OIL LEVEL INDICATOR

The word “Oil” stamped on the dipstick has been removed to comply with global labeling laws.

SIGHT SHIELD REVISED FOR CHEVROLET SILVERADO, SUBURABAN AND AVALANCHE AND GMC SIERRA AND YUKON XL

The thermoplastic sight shield or ``Vortec 8100 cover’’ around the 8.1L intake manifold and fuel rail has been revised to fit over the new throttle body. The sight shield dampens mechanical noise from the engine and gives the Vortec 8100 its up-to-date, finished look.

STARTER FOR SILVERADO, SUBURABAN, AVALANCHE, SIERRA AND YUKON XL

8.1Ls built for these applications are equipped with a different starter than other applications. Specifications are virtually identical, but this starter motor requires no heat shield and offers mass and packaging advantages. These applications now require a smaller heat shield for the knock sensor.


EXHAUST VALVES REVISED ON MARINE VARIANT

Exhaust valves on 8.1Ls built for marine applications are no longer treated with a Stellite surface hardener. There is no functional change for the customer. The Stellite-faced valves for marine use date to the leaded-fuel variant of the engine. Production of leaded-fuel 8.1Ls ended after the 2001 model year. All export engines are now built to U.S federal emission standards, which ensures that all Vortec 8100s produce the fewest exhaust emissions possible and allows GM Powertrain to focus further development on a common engine.

OVERVIEW

Introduced in the 2001 Chevrolet Silverado and Suburban and GMC Sierra and Yukon XL, the 8.1L is the legendary GM Big Block for a new millennium, with a longer expected useful life and horsepower and torque that surpass the competition. GM's leadership in big-block V8 technology dates to 1958, when the Vortec 8100's progenitor was launched with 348 cubic inches of displacement, in the full-size 1958 Chevrolets. The 348 was followed by several variants, including a 409, 366 and 427. In 1970, the 454-cubic-inch big-block was introduced. It was retooled in 1991 as the Vortec 7400--a truly powerful pickup engine that met stringent 1990s emission requirements. The Vortec 8100 bears little resemblance to those engines, beyond its bore centers and bore diameters, but it maintains a tradition of outstanding durability and class-leading power. Based on published figures in January 2002, the engine delivers more horsepower and torque than any gasoline engine in the heavy-duty pickup market.

After extensive analysis of competitors' engines, the 8.1L development team set a goal of 200,000 miles of useful life without major repairs--and then achieved it. The engine has been tested and validated to meet this 200,000-mile durability standard. Before it was ready for production, the 8.1L had to pass the ``Marine Dock'' test, in which it is run at full throttle for 300 consecutive hours, and a minimum of 1000 hours at full-throttle operation for truck applications. .

Durability is only one component of success in the heavy-duty pickup market. Another is outstanding power, and measured by both horsepower and torque, the Vortec 8100 beats its V10 competition.

 

[Larry]

Vortec 8100 8.1L V-8 (L18)

2004 Model Year Summary

· Returnless fuel injection for Chevrolet Avalanche, Silverado and Suburban, GMC Sierra and Yukon XL and Workhorse Custom Chassis

· Low permeability intake manifold body gaskets

· Improved onboard refueling vapor recovery (ORVR) system for Avalanche, Silverado, Suburban, Sierra and Yukon XL

· Exhaust gas recirculation (EGR) eliminated

· Improved crank and cam timing sensors

· Improved crankshaft seal

· Adjustable throttle pedal for Workhorse Custom Chassis

· Revised cylinder heads for industrial applications

FULL DESCRIPTIONS OF NEW OR CHANGED FEATURES:


RETURNLESS FUEL INJECTION FOR CHEVROLET AVALANCHE, SILVERADO AND SUBURBAN, GMC SIERRA AND YUKON XL AND WORKHORSE CUSTOM CHASSIS

All Vortec 8100s built for these applications are equipped with a new "returnless" fuel injection system that eliminates fuel return lines between the engine and the gasoline tank. The new fuel system is also known as a demand system.

Before model year 2004, the Vortec 8100’s sequential fuel injection (SFI) used a return line to manage fuel pressure by bleeding off excess fuel at the fuel rail and returning the excess to the tank. The new system eliminates the return lines and moves the fuel-pressure regulator from the fuel rail on the engine to the fuel tank. The fuel line from the tank now includes pulse dampeners, or a series of baffles, that manage fuel pulsing and limit noise.

Because it delivers only the amount of fuel need by the injectors, and returns no fuel to the gas tank, the returnless system essentially eliminates heat transfer from the engine to tank. This reduces the amount of vapor generated in the tank, and captured by the evaporative emissions control system.

Vortec 8100s built for the medium-duty Chevrolet Kodiak and GMC Topkick, as well as those built for marine and industrial applications, continue with fuel injection managed with return lines.

LOW PERMEABILITY INTAKE MANIFOLD AND THROTTLE BODY GASKETS

The Vortec 8100 has new intake manifold sealing gaskets manufactured from a fluorocarbon material. These fluorocarbon gaskets represent the best sealing technology available. The gaskets are resistant to most chemicals, for maximum durability, and particularly impermeable to small hydrocarbon molecules. Gasoline vapor cannot penetrate the fluorocarbon. Moreover, the gaskets are designed to improve sealing for the life of the engine. They are molded with slight protrusions, or ``snouts,’’ that fit into counter-bores milled in the cylinder heads. The snouts more positively locate the gaskets and virtually eliminate the possibility of movement during assembly or after repeated thermal cycling over the life of the engine.

IMPROVED ONBOARD REFUELING VAPOR RECOVERY (ORVR) SYSTEM FOR CHEVROLET AVALANCHE AND SILVERADO, GMC SIERRA AND YUKON XL

The ORVR system on these Vortec 8100-equipped vehicles uses a new evaporative emissions canister and purge-control solenoid. ORVR reduces evaporative emissions by preventing gasoline vapor from escaping into the atmosphere during refueling. These new ORVR components take full advantage of advanced technology built into the Vortec 8100's P59 Powertrain Control Module (PCM). The PCM and new components more efficiently manage ORVR, and improve the accuracy and robustness of the OBDII (On-Board Diagnostics) system. This precision will reduce the number of false alarms – OBDII ``service engine’’ warning lights – that require dealer intervention. With improvements to ORVR, the returnless fuel injection and low-permeability gaskets, the Vortec 8100 meets new, near-zero evaporative emissions standards mandated for 2004.


EXHAUST GAS RECIRCULATION (EGR) ELIMINATED

The EGR control valve and plumbing have been removed from all Vortec 8100s. The EGR system was used to recycle some exhaust gas back into the intake stream to cool combustion and reduce oxides of nitrogen (NOx) emissions. Data from development and durability test vehicles indicates that software refinements in the P59 PCM, and the engine’s overall efficiency, allow the Vortec 8100 to meet all 2004 North American exhaust emissions standards without EGR. Removing EGR reduces cost, complexity and potential warranty claims, improving both assembly efficiency and reliability.

IMPROVED CRANK AND CAM TIMING SENSORS

Vortec 8100s are equipped with new crankshaft and camshaft timing sensors. The sensors continue to operate on the Magnetic Reluctance (MR) or “mirror image” ignition timing principle, ensuring precise measurement over the life of the engine without adjustment. These sensors are now common with those used on other Vortec V-8s, helping streamline purchasing requirements, reducing inventory requirements and increasing efficiency at engine assembly plants.

IMPROVED CRANKSHAFT SEAL

The Vortec 8100 has a new front engine cover with a redesigned crankshaft seal. The seal requires no particular orientation during installation. It reduces engine assembly time and virtually eliminates the possibility of misalignment.

ADJUSTABLE THROTTLE PEDAL FOR WORKHORSE CUSTOM CHASSIS

WCC commercial vehicles will be offered with a throttle pedal that can be moved to accommodate different drivers. Vortec 8100s built for this application require PCM software recalibration to manage the electronic throttle control. There are no hardware changes.

REVISED CYLINDER HEADS FOR INDUSTRIAL APPLICATIONS

Vortec 8100s built for industrial use have new valve and valve seat material and new springs. Industrial engines typically operate at relatively low, steady rpm (1800-2000), creating different demands than the typical truck duty cycle. The valve seats in industrial Vortec 8100s have been metallurgically improved with induction hardening, and valve-spring tension has been reduced to soften valve interaction with the seats during low speed operation. Finally, industrial engines are now equipped with the same Silcrome 1 valves used in Vortec 8100s built for trucks. This material includes tungsten, vanadium, manganese and silicone, with higher chromium content than conventional iron valve alloy. The Silicrome 1 valves ensure long-term durability in industrial engines and increase efficiency at the engine plant by reducing inventory.

OVERVIEW

The 8.1L L18 Vortec 8100 V-8 is the legendary GM Big Block for a new millennium, with a longer expected useful life and horsepower and torque that surpass the large displacement gasoline engines offered in competitors’ heavy-duty pickups. Introduced in the 2001 Chevrolet Silverado and Suburban and GMC Sierra and Yukon XL, the Vortec 8100 was essentially a new engine. Nearly 90 percent of its parts have been completely redesigned. While it shares its valve centers, bore centers and bore diameter with the previous 7.4L Big Block, stroke was increased 9.4 mm (.37 inch) to increase displacement 700 cc. The process of refining the engine block was similar to the one GM Powertrain engineers applied when they turned the small-block V-8 into the Gen III. The latest math-based engineering tools were used to improve the flow and distribution of oil and coolant, to refine castings and to improve production quality and efficiency.

After extensive analysis of competitors' engines, the Vortec 8100 development team set a goal of 200,000 miles of useful life without major repairs – and then achieved it. Before it was ready for production, this big block had to pass the ``Marine Dock'' test, in which it is run at full throttle for 300 consecutive hours without a hitch, and a minimum of 1,000 hours at full-throttle operation for truck applications. The Vortec 8100 was greeted at launch with rave reviews from the media and customers alike. Yet in the three years since, virtually every aspect of the engine – from sealing to electronic management to noise, vibration and harshness control – has been re-examined and improved.

GM's leadership in big-block V-8 technology dates to at least 1958, when the Vortec 8100's progenitor was launched with 348 cubic inches of displacement in the full-size 1958 Chevrolets. The 348 was followed by several variants, including a 409, 366 and 427. In 1970, the 454-cubic-inch big-block was introduced. It was retooled in 1991 as the Vortec 7400 – a truly powerful pickup engine that met stringent 1990s emission requirements. The Vortec 8100 bears little resemblance to those engines, but it maintains a tradition of outstanding durability and class-leading power. By nearly every objective measure, the Vortec 8100 beats its V-10 competition.

 

[Larry]

Vortec 8100 8.1L V-8 (L18)

2005 Model Year Summary

· New for Chevrolet Kodiak and GMC TopKick with four-wheel drive

· Floating pin pistons

· Returnless fuel injection for marine applications

· Improved oil pan (for medium duty applications)

· Improved throttle actuator control module

· Rate-based diagnostics

· GF-4 engine oil

FULL DESCRIPTIONS OF NEW OR CHANGED FEATURES:


NEW FOR CHEVROLET KODIAK AND GMC TOPKICK WITH FOUR-WHEEL DRIVE

For 2005, the Vortec 8100 will be available in Chevrolet Kodiak and GMC Topkick medium-duty trucks with four-wheel drive. Vortec 8100s built for this application require packaging adjustments to accommodate a front transaxle, including exhaust manifolds, heat shields and starter motor.

FLOATING PIN PISTONS

The Vortec 8100 is fitted with new floating-pin pistons. Introduced previously on GM Powertrain’s Vortec 6000 V-8, these pistons feature wrist pins that “float” inside the rod bushing and the pin bores in the piston barrel. Previously, the Vortec 8100 used a fixed-pin assembly, in which the connecting rod is fixed to the piston’s wrist pin, and the pin rotates in the pin bore. In the Vortec 8100, snap rings now retain the wrist pin in the piston, while the rod moves laterally on a bushing around the pin.

The Vortec 8100’s pistons, piston rings and connecting rods are identical to those used in 2004. The new floating-pin assembly allows tighter pin to pin-bore tolerances and reduces noise generated during engine operation.

RETURNLESS FUEL INJECTION FOR MARINE APPLICATIONS

All Vortec 8100s built for marine application are equipped with a new ``returnless’’ fuel injection system that eliminates fuel return lines between the engine and the gasoline tank. The new fuel system is also known as a demand system, and was introduced on Vortec 8100s built for the Chevrolet Silverado and GMC Sierra for model year 2004.

Before model year 2004, the sequential fuel injection (SFI) on all Vortec 8100s used a return line to manage fuel pressure by bleeding off excess fuel at the fuel rail and returning the excess to the tank. The new system eliminates the return lines and moves the fuel pressure regulator from the fuel rail on the engine to the fuel tank. The fuel line from the tank now includes pulse dampeners, or a series of baffles, that manage fuel pulsing and limit noise.

Because it delivers only the amount of fuel need by the injectors, and returns no fuel to the gas tank, the returnless system essentially eliminates heat transfer from the engine to tank. This reduces the amount of vapor generated in the tank and released as evaporation. The returnless system has been introduced on marine engines to give marine customers the same emissions standards and efficient operation as truck customers.

IMPROVED OIL PAN FOR MEDIUM DUTY AND MARINE APPLICATIONS

The oil pan on Vortec 8100s built for medium-duty (C4-C8 trucks) and marine use has been redesigned. This cast aluminum oil pan is essentially identical for both applications, with differences limited to final machining.

With the new pan, the interior baffle has been reconfigured to maximize oil flow, improve durability and stiffen the cast-aluminum pan’s structure, further reducing engine vibration. Moreover, sump capacity for medium-duty trucks increases 3.1 liters. The change was driven by the demands of the commercial fleet and rental markets. Rental truck customers may not be the most diligent operators when it comes to monitoring oil levels. The larger sump adds an extra measure of security for rental companies and fleet operators, even if customers use trucks for weeks without checking oil levels.

IMPROVED THROTTLE ACTUATOR CONTROL MODULE

All Vortec 8100’s are equipped with an improved throttle actuator control (TAC) module. Located on the throttle body, the TAC module is an integral component of the Vortec 8100’s electronic throttle control (ETC) system. The TAC takes command from the powertrain control module (PCM) and then operates the motor that opens and closes the throttle plate.

The TAC module has new read-only memory and control software. Like its predecessor, it allows multiple throttle progressions or algorithms, which operate the throttle at varying rates according to operating conditions and driver demands. It also has built-in default settings that protect the engine and ensure safe operation in the event of malfunction with the ETC or other engine subsystems.

RATE-BASED DIAGNOSTICS

The Vortec 8100’s powertrain control module (PCM) uses a new monitoring protocol known as rate-based diagnostics. Rate-based diagnostics improve the robustness of the Onboard Diagnostics System (OBD II) and ensure optimal performance of emissions control systems.

With rate-based diagnostics, the PCM applies a new formula to manage OBD II. Essentially, new software increases the frequency at which the PCM checks various engine systems, and particularly emissions-control systems such as the catalytic converter, oxygen sensors and exhaust gas recirculation (EGR). Rate-based diagnostics more reliably monitor real-word operation of these systems, and allow regulatory agencies to more easily measure and certify emissions compliance. The new protocol allows the Vortec 8100 to meet more stringent OBD II requirements two years ahead of a mandate by the California Air Resources Board.

GF-4 ENGINE OIL

All Vortec 8100s will be shipped to customers with a new engine oil that reduces engine deposits, extends oil change intervals, improves fuel economy and extends the life of emissions control systems. GM Powertrain has taken a leading role in developing and introducing the new oil, designated GF-4 (for “Gasoline Fueled, Standard 4’’) by the American Petroleum Institute.

GF-4 contains a new ash-free antioxidant ingredient and less phosphorous than the previous formulation (GF-3). The typical automotive engine now operates at a much higher temperature than an engine built 10 years ago. GF-4 is twice as resistant to oxidizing, which can present itself as foaming, at high operating temperatures. At the same time, GF-4 provides better low-temperature protection, reducing engine wear during the critical cold-start period. Lower phosphorus and sulfur content – chemicals that are harmful to catalytic converters – will extend anticipated catalyst life beyond 120,000 miles. Finally, GF-4 lowers friction overall and retains its optimal friction-reducing characteristics longer. The result is an anticipated improvement of 0.2 percent to 0.3 percent in an engine’s fuel economy, and longer oil change intervals.

Production of Vortec 8100s with GF-4 begin in fall 2004, ahead of an industry recommendation of April 30, 2005. This will allow vehicles with the Vortec 8100 to be tested for 2005 Corporate Average Fuel Economy (CAFE) standards with GF-4. GM’s industry-leading Oil Life System may be adjusted to account for the new oil. The owner’s manual in vehicles equipped with the Vortec 8100 will continue to recommend oil with the Starburst logo, which must be certified to GF-4 by May 2005.

OVERVIEW

Few words generate excitement for car and truck enthusiasts like ‘’Big Block.’’ The Vortec 8100 V-8 is the legendary GM Big Block for a new millennium, with a longer expected useful life and horsepower and torque that surpass the large displacement gasoline engines offered in competitors’ heavy-duty pickups. This heavy-duty engine also sets benchmarks for marine and industrial application worldwide.

Introduced in the 2001 Chevrolet Silverado and Suburban and GMC Sierra and Yukon XL, the Vortec 8100 was essentially a new engine. Nearly 90 percent of its parts have been completely redesigned. While it shares its valve centers, bore centers and bore diameter with the previous 7.4L Big Block, stroke was increased 9.4 mm (.37 inch) to increase displacement 700 cc. The latest math-based engineering tools were used to improve the flow and distribution of oil and coolant, to refine castings and to improve production quality and efficiency.

After extensive analysis of competitors' engines, the Vortec 8100 development team set a goal of 200,000 miles of useful life without major repairs – and then achieved it. Before it was ready for production, this big block had to pass the “Marine Dock'' test, in which it is run at full throttle for 300 consecutive hours without a failure, and a minimum of 1,000 hours at full-throttle operation for truck applications.

In the four years since its launch, virtually every aspect of the engine – from sealing to electronic management to noise, vibration and harshness control – has been re-examined and improved. For 2004, Vortec 8100s built for truck installation were equipped with a new returnless fuel injection system that eliminated fuel return lines between the engine and the gasoline tank and reduced evaporative emissions. Combined with new intake manifold and throttle body gaskets, manufactured of an advanced fluorocarbon material that is virtually impermeable to hydrocarbon molecules, the returnless fuel system allows the Vortec 8100 to meet near-zero evaporative emissions standards. Also in 2004, Vortec 8100s built for industrial applications were equipped with new valves, valve seat material and springs designed expressly for industrial operation at low, steady rpm.

GM's leadership in big-block V-8 technology dates to at least 1958, when the Vortec 8100's progenitor was launched with 348 cubic inches of displacement in the full-size 1958 Chevrolets. The 348 was followed by several variants, including a 409, 366 and 427. In 1970, the 454-cubic-inch big-block was introduced. It was retooled in 1991 as the Vortec 7400 – a truly powerful pickup engine that met stringent 1990s emission requirements. The Vortec 8100 bears little resemblance to those engines, but it maintains a tradition of outstanding durability and class-leading power.

 

[Larry]

VORTEC 8100 8.1L V-8 (L18)

2006 model year summary

• Increase to 325 horsepower for Chevrolet Suburban, Avalanche and GMC Yukon XL
• New dual mid-coupled converter system
• Returnless fuel injection for Chevrolet Kodiak and GMC TopKick
• Improved electronic throttle control pedal and throttle actuator control (TAC) module
• Recalibrated P59 engine controller

Full descriptions of new or changes features:

Increase to 325 horsepower
For the 2006 Chevrolet Suburban, Avalanche and GMC Yukon XL 2500 Series, the Vortec 8100 delivers an additional 5 horsepower. Increased power results from reduced backpressure in the exhaust system, enabled by a new catalytic converter system. The new converter system is primarily designed to lower emissions. The Vortec 8100’s new rating is 325 horsepower and 447 lb.-ft. of torque.

New dual mid-coupled catalytic converter system

Chevrolet Suburban, Avalanche and GMC Yukon XL three-quarter-ton models equipped with the Vortec 8100 receive a new M120 mid-coupled catalytic converter system. Two new mid-coupled converters replace four previous ones (two mid-coupled and two under-floor converters). The new dual converters, with about two liters of volume, are also located closer to the exhaust manifold to enhance their effectiveness. Their construction, consisting of multiple materials, is unchanged. While providing lower LEV emissions levels, the new converter system also allows a more moderate 47.1 kPa of exhaust back pressure for more power. Induction restriction is unchanged.

Improved electronic throttle control and throttle actuator control module

With the Vortec 8100, the Chevrolet Suburban, Avalanche and GMC Yukon XL 2500 Series also receive an improved electronic throttle control pedal and improved throttle actuator control (TAC) module. The throttle pedal provides more consistent truck-to-truck pedal force and effort feel for vehicle operators. The TAC is designed to accommodate the new pedal.

Located on the engine side of the front of dash, the TAC module is an integral component of the Vortec 8100’s electronic throttle control (ETC) system. The TAC takes command from the powertrain control module (PCM) and then operates the motor that opens and closes the throttle plate.

Like its predecessor, the TAC module has read-only memory and control software. It allows multiple throttle progressions or algorithms, which operate the throttle at varying rates according to operating conditions and driver demands. It also has built-in default settings that protect the engine and ensure safe operation in the event of malfunction with the ETC or other engine subsystems.

Returnless fuel injection for Chevrolet Kodiak and GMC TopKick

For 2006, the Vortec 8100 available in Chevrolet Kodiak and GMC Topkick medium duty trucks is equipped with a new "returnless" fuel injection system that eliminates fuel return lines between the engine and the gasoline tank. The new fuel system is also known as a demand system. The system is already used with the Vortec 8100 on Chevrolet Silverado and GMC Sierra models and with all Vortec 8100s built for marine applications. Before 2006, the Sequential Fuel Injection (SFI) in medium duty trucks equipped with the Vortec 8100 used a return line to manage fuel pressure by bleeding off excess fuel at the fuel rail and returning the excess to the fuel tank. The new system eliminates the return lines and moves the fuel-pressure regulator from the fuel rail on the engine to the fuel tank. But because the returnless system delivers only the amount of fuel needed by the injectors, and returns no fuel to the fuel tank, it eliminates heat transfer from the engine to the fuel tank. This reduces the amount of vapor generated in the tank and captured by the evaporative emissions control system.

Recalibrated P59 engine controller

The Vortec 8100’s P59 engine controller in medium duty trucks is recalibrated to coordinate with the newly available version of the Allison five-speed automatic transmission and the returnless fuel injection system. The P59 also has new calibrations to optimize driveability and fuel economy with the new Allison six-speed automatic transmission being introduced for the first time in GM full-size pickups.

Overview
Few words generate excitement for car and truck enthusiasts like ‘’Big Block.’’ The Vortec 8100 V-8 is the legendary GM Big Block for a new millennium, with a longer expected useful life and horsepower and torque that surpass the large-displacement gasoline engines offered in competitors’ heavy-duty pickups. This heavy-duty engine also sets benchmarks for marine and industrial application worldwide.

Introduced in the 2001 Chevrolet Silverado and Suburban and GMC Sierra and Yukon XL, the Vortec 8100 was essentially a new engine. Nearly 90 percent of its parts have been completely redesigned. While it shares its valve centers, bore centers and bore diameter with the previous 7.4L big block, stroke was increased 9.4 mm (.37 inch) to increase displacement 700 cc. The latest math-based engineering tools were used to improve the flow and distribution of oil and coolant, to refine castings and to improve production quality and efficiency.
After extensive analysis of competitors' engines, the Vortec 8100 development team set a goal of 200,000 miles of useful life without major repairs – and achieved it. Before it was ready for production, this big block had to pass the “Marine Dock'' test, in which it is run at full throttle for 300 consecutive hours without a failure, and a minimum of 1,000 hours at full-throttle operation for truck applications.

In the five years since its launch, virtually every aspect of the engine – from sealing to electronic management to noise, vibration and harshness control – has been re-examined and improved.

For 2005, the Vortec 8100 was made available in Chevrolet Kodiak and GMC TopKick trucks with four-wheel drive. GM’s big block was fitted with floating-pin piston rings, which allow tighter pin to pin-bore tolerances for quieter operation and increased durability. Returnless fuel injection was incorporated in all marine applications. Medium duty trucks received an improved oil pan. All Vortec 8100s received an improved throttle actuator control. Their powertrain control module began using a monitoring protocol, known as rate-based diagnostics, to increase the robustness of the Onboard Diagnostics System and optimize performance of the emissions control systems. All Vortec 8100s
began being shipped with GF-4 engine oil that reduces engine deposits, extends oil change intervals, improves fuel economy and extends the life of emissions control systems.

For 2004, Vortec 8100s built for Chevrolet Silverado and GMC Sierra pickups were equipped with a new returnless fuel injection system that eliminates fuel return lines between the engine and the gasoline tank and reduces evaporative emissions. Combined with new intake manifold and throttle body gaskets, manufactured of an advanced fluorocarbon material that is virtually impermeable to hydrocarbon molecules, the returnless fuel system allows the Vortec 8100 to meet near-zero evaporative emissions standards. Also in 2004, Vortec 8100s built for industrial applications were equipped with new valves, valve seat material and springs designed expressly for industrial operation at low, steady rpm.

GM's leadership in big block V-8 technology dates to at least 1958, when the Vortec 8100's progenitor was launched with 348 cubic inches of displacement in the full-size 1958 Chevrolets. The 348 was followed by several variants, including a 409, 366 and 427. In 1970, the 454-cubic-inch big-block was introduced. It was retooled in 1991 as the Vortec 7400 – a truly powerful pickup engine that met stringent 1990s emission requirements. The Vortec 8100 bears little resemblance to those engines, but it maintains a tradition of outstanding durability and class-leading power.

 

[Larry]

2007 Vortec 8.1L V8 (L18)

Vortec 8.1L V8 (L18) Truck Engine

2007 model year summary

• Hexavalent Chrome Eliminated


Full descriptions of new or changes features:

HEXAVALENT CHROME ELIMINATED

An ongoing process to eliminate heavy metals from engines results in one small component—the drain plug—being replaced by a hexavalent chrome-free part.

Overview

Few words generate excitement for car and truck enthusiasts like ‘’Big Block.’’ The Vortec 8.1L V8 is the legendary GM Big Block for a new millennium, with a longer expected useful life and horsepower and torque that surpass the large-displacement gasoline engines offered in competitors’ heavy-duty pickups. This heavy-duty engine also sets benchmarks for marine and industrial applications worldwide.

Introduced in the 2001 Chevrolet Silverado and Suburban and GMC Sierra and Yukon XL, the Vortec 8.1L was essentially a new engine. Nearly 90 percent of its parts were completely redesigned. While it shares its valve centers, bore centers and bore diameter with the previous 7.4L big block, stroke was increased 9.4 mm (0.37 inch) to increase displacement 700 cc. The latest math-based engineering tools were used to improve the flow and distribution of oil and coolant, to refine castings and to improve production quality and efficiency.

Power was increased for the 2006 Chevrolet Suburban, Avalanche and GMC Yukon XL 2500 Series, by reduced backpressure in the exhaust system, enabled by a new catalytic converter system. The new converter system is primarily designed to lower emissions. The new catalytic converter system has two new mid-coupled converters which replace four previous ones. The dual converters, with about two liters of volume, are also located closer to the exhaust manifold to enhance their effectiveness. While providing lower emissions levels, the new converter system also allows a more moderate 47.1 kPa of exhaust back pressure for more power. Induction restriction was unchanged.

Also for 2006, the 8.1L V8-equipped Chevrolet Suburban, Avalanche and GMC Yukon XL 2500 Series received an improved electronic throttle control pedal and improved throttle actuator control (TAC) module. The throttle pedal provides more consistent truck-to-truck pedal force and effort feel for vehicle operators. The TAC is designed to accommodate the new pedal. Located on the engine side of the front of the dash, the TAC module is an integral component of the Vortec 8.1L’s electronic throttle control (ETC) system. The TAC takes command from the powertrain control module (PCM) and then operates the motor that opens and closes the throttle plate. Like its predecessor, the TAC module has read-only memory and control software. It allows multiple throttle progressions or algorithms, which operate the throttle at varying rates according to operating conditions and driver demands. It also has built-in default settings that protect the engine and ensure safe operation in the event of malfunction with the ETC or other engine subsystems.

The Vortec 8.1L’s P59 engine controller in medium duty trucks was recalibrated for 2006 to coordinate with the newly available version of the Allison five-speed automatic transmission and the returnless fuel injection system (see below). The P59 also has new calibrations to optimize driveability and fuel economy with the new Allison six-speed automatic transmission being introduced for the first time in GM full-size pickups.

Finally, for 2006, the Vortec 8.1L available in Chevrolet Kodiak and GMC Topkick medium duty trucks was equipped with a new "returnless" fuel injection system that eliminates fuel return lines between the engine and the gasoline tank. The new fuel system is also known as a demand system. The system is already used with the Vortec 8.1L on Chevrolet Silverado and GMC Sierra models and with all Vortec 8.1Ls built for marine applications.

Before 2006, the Sequential Fuel Injection (SFI) in medium duty trucks equipped with the Vortec 8.1L used a return line to manage fuel pressure by bleeding off excess fuel at the fuel rail and returning the excess to the fuel tank. The new system eliminates the return lines and moves the fuel-pressure regulator from the fuel rail on the engine to the fuel tank. But because the returnless system delivers only the amount of fuel needed by the injectors, and returns no fuel to the fuel tank, it eliminates heat transfer from the engine to the fuel tank. This reduces the amount of vapor generated in the tank and captured by the evaporative emissions control system.

After extensive analysis of competitors' engines, the Vortec 8.1L development team set a goal of 200,000 miles of useful life without major repairs – and achieved it. Before it was ready for production, this big block had to pass the “Marine Dock'' test, in which it is run at full throttle for 300 consecutive hours without a failure, and a minimum of 1,000 hours at full-throttle operation for truck applications.

In the six years since its launch, virtually every aspect of the engine – from sealing to electronic management to noise, vibration and harshness control – has been re-examined and improved.

GM's leadership in big block V8 technology dates to at least 1958, when the Vortec 8.1L's progenitor was launched with 348 cubic inches of displacement in the full-size 1958 Chevrolets. The 348 was followed by several variants, including a 409, 366 and 427. In 1970, the 454-cubic-inch big-block was introduced. It was retooled in 1991 as the Vortec 7400 – a truly powerful pickup engine that met stringent 1990s emission requirements. The Vortec 8.1L bears little resemblance to those engines, but it maintains a tradition of outstanding durability and class-leading power.

 

[Larry]

2008 Vortec 8.1L V8 (L18)

Vortec 8.1L V8 (L18) Truck Engine

2008 model year summary

Carryover content and benefits from 2007 model year

Overview

Few words generate excitement for car and truck enthusiasts like ‘’Big Block.’’ The Vortec 8.1L V8 is the legendary GM Big Block for a new millennium, with a longer expected useful life and horsepower and torque that surpass the large-displacement gasoline engines offered in competitors’ heavy-duty pickups (is this statement still correct?). This heavy-duty engine also sets benchmarks for marine and industrial applications worldwide.

Introduced in 2001, the Vortec 8.1L was essentially a new engine. Nearly 90 percent of its parts were completely redesigned. While it shares its valve centers, bore centers and bore diameter with the previous 7.4L big block, stroke was increased 9.4 mm (0.37 inch) to increase displacement 700 cc. The latest math-based engineering tools were used to improve the flow and distribution of oil and coolant, to refine castings and to improve production quality and efficiency.

The Vortec 8.1L’s P59 engine controller in medium duty trucks was recalibrated for 2006 to coordinate with the newly available version of the Allison five-speed automatic transmission and the returnless fuel injection system (see below).

Finally, for 2006, the Vortec 8.1L available in Chevrolet Kodiak and GMC Topkick medium duty trucks was equipped with a new "returnless" fuel injection system that eliminates fuel return lines between the engine and the gasoline tank. The new fuel system is also known as a demand system. The system is already used with all Vortec 8.1Ls built for marine applications.

Before 2006, the Sequential Fuel Injection (SFI) in medium duty trucks equipped with the Vortec 8.1L used a return line to manage fuel pressure by bleeding off excess fuel at the fuel rail and returning the excess to the fuel tank. The new system eliminates the return lines and moves the fuel-pressure regulator from the fuel rail on the engine to the fuel tank. But because the returnless system delivers only the amount of fuel needed by the injectors, and returns no fuel to the fuel tank, it eliminates heat transfer from the engine to the fuel tank. This reduces the amount of vapor generated in the tank and captured by the evaporative emissions control system.

After extensive analysis of competitors' engines, the Vortec 8.1L development team set a goal of 200,000 miles of useful life without major repairs – and achieved it. Before it was ready for production, this big block had to pass the “Marine Dock'' test, in which it is run at full throttle for 300 consecutive hours without a failure, and a minimum of 1,000 hours at full-throttle operation for truck applications.

In the eight years since its launch, virtually every aspect of the engine – from sealing to electronic management to noise, vibration and harshness control – has been re-examined and improved.

GM's leadership in big block V8 technology dates to at least 1958, when the Vortec 8.1L's progenitor was launched with 348 cubic inches of displacement in the full-size 1958 Chevrolets. The 348 was followed by several variants, including a 409, 366 and 427. In 1970, the 454-cubic-inch big-block was introduced. It was retooled in 1991 as the Vortec 7400 – a truly powerful pickup engine that met stringent 1990s emission requirements. The Vortec 8.1L bears little resemblance to those engines, but it maintains a tradition of outstanding durability and class-leading power.



2009 Vortec 8.1L V-8 (L18)

Vortec 8.1L V-8 (L18) Truck Engine

2009 model year summary

Carryover content and benefits from 2008 model year

Basically no notable changes to the engine from the 2007 Model Year to the end of engine production in late 2009.

 

[Larry]

Probably the most common question I get is how does one convert a Silverado/Sierra engine to the G-Van/Workhorse/Medium Duty accessory bracket setup in order to move the A/C compressor up high and out of the way of the frame. The high mount A/C bracket set up is near impossible to find in salvage yards but are still available through GM service parts. If you want them, you pretty much have to buy them new. I suspected the supply of these parts to dry up at GMSPO but with PSI using these brackets as their main bracket setup on their production engines should help keep the supply flow going.

Water Pump: First, this truck water pump needs to be removed

Then install this water pump. Notice the water outlet is in a different location similar to the old SBC and BBC engines. The water pump length is also different from the Silverado/Sierra WP. Napa part number for this water pump is WP 58565 (reman) or TFW 44089 (new)

Crank Pulley/Balancer Assembly: Next step is to replace the Silverado/Sierra pulley/balance with this one. GM Part number 12555140

A/C-P/S Bracket: This is the A/C - P/S Bracket for use with a Saginaw PS pump. GM part number 12558927. It looks just like the L29 7.4L bracket but the bolt holes to the block are in different locations. A L29 bracket cannot be used on an L18. No idler goes in the idler provision unless you are running A/C delete. This is the bracket I run on my K10
Update: April 6, 2019: See post #417 for updated information on alternatives to the extinct 12558927 A/C – PS bracket

There is also a similar bracket to the pictured above but only allows for a ZF PS pump. Notice how square the PS pump mounting area is. Do not use this bracket unless you plan to run a ZF pump. From my experience, the ZF pump does not fit in the frame rails of older GM trucks. GM Part number 12563068.

Alternator bracket: This is a Workhorse alternator bracket, Part number W0003928 which accepts a CS-144 alternator. This is the bracket I run on my K10. The belt tensioner part number is 12581203 and the tensioner bolt is 11516367 and the idler pulley that bolts on this bracket is 12580771

There is also an alternator bracket of 12559613 that was used on G-vans and medium duty. I do not know what is different about this one vs. the Workhorse bracket above but they carry different part numbers.

Coolant Crossover: This is one part you do want from a Silverado/Sierra engine. The coolant crossover in this picture is a the G-Van/Workhorse/Medium Duty piece that puts the upper radiator hose/tstate housing in a horrible spot, right in the middle of the engine. If you need a Silverado/Sierra crossover the part number is 12578330

The Silverado/Sierra crossover (12578330) will put your upper radiator hose here

Dual Alternator Bracket (12563070) This bracket looks to work with the Workhorse, G-van, Medium duty water pump, crank pulley & A/C compressor

This website has a great GM online parts catalog with pictures for looking up part numbers. The bad thing is they blank out the first two digits of the part number. For what it is worth, most L18 part numbers start with a 11, 12 or 15 prefix. Once you find your part number you can go here to verify the 11,12, or 15 prefix is correct for the part description and check pricing. GM Parts Direct whores parts at very low margins (0 to less than 5% markup) but screws you blue on freight but their website is really nice to see what dealer cost is.

Kent-Moore L18 Essential Tool Kit: J-44900

 

[Engineered Vintage]

Larry - I love that you have posted this information! You are the man:

I would like to add this bit of information I have collected (including a PM exchange we had awhile back)

I'm doing this same swap in my Blazer (a '72) and have spoken with Larry at length.

1) The mechanical throttle body you want is on the Gen 6 454 engines - it will bolt right on - but you will likely need a throttle body spacer to make it fit. Here is one on Ebay - but you could probably find it cheaper:

http://cgi.ebay.com/ebaymotors/96-99...Q5fAccessories

Note that these throttle bodies have the TPS in the side.

2) Wiring harness source:

http://www.jimsperformance.com/





Some misc links on 8.1:
http://67-72chevytrucks.com/vboard/s...d.php?t=400053
http://67-72chevytrucks.com/vboard/s...d.php?t=374432
http://67-72chevytrucks.com/vboard/s...d.php?t=373400


http://coloradok5.com/forums/showthr...highlight=8100
http://www.hotrodlane.cc/81bbc/81bbc.html
http://coloradok5.com/forums/showthr...engine+support

http://www.jimsperformance.com/links.html
http://www.pirate4x4.com/forum/showt...=598547&page=1
http://www.pirate4x4.com/forum/showt...=598547&page=9
http://pirate4x4.com/forum/showthread.php?t=631745
http://www.pirate4x4.com/forum/showt...t=#post8452724

http://www.4wheeloffroad.com/brandpa...t_1/index.html
http://www.67-72chevytrucks.com/vboa...ight=8.1+4l80e
http://www.pirate4x4.com/forum/showthread.php?t=845109
http://www.pirate4x4.com/forum/showthread.php?t=457799
http://www.pirate4x4.com/forum/showthread.php?t=659156
http://www.pirate4x4.com/forum/showthread.php?t=667616





Here is some correspondence between Larry & I:

Mr. Dirty Larry:

Hello, my name is Ben - I live in Portland, OR. In the process of a frame off on a '72 K5. I've been reading your posts thoroughly over the past few weeks to learn as much as possible about 8.1s in older rigs.

I currently have an 8.1 in my '02 GMC Crew that I bought new. Love that engine - has 110K and still going strong.

I closed the deal on an '01 8.1 complete block today. Has wiring harness, CPU, accessories, pedal, alt, starter, etc, etc... This engine has supposedly:

A) 96K miles
B) was in '01 truck
C) was looked over by GM Master Tech who said it was a good running strong engine


I have two questions for you:

1) What should my first steps be after I get this engine? Can I simply drop it in and go? Or should I plan to do head gaskets, spark plugs, etc...

2) Do you have the GM part number for the Top Kick bracket to move the alternator to top passenger side of engine and ac pump to top driver side?

Thank you in advance for your help!

-Ben



Hello Ben,

Sounds like a great project. I also bought a 2001 HD 4x4 with an 8.1L and ZF 6-speed manual brand new when GM first came out with the zero percent interest after 9-11-01. It now has 53K miles and has been a great truck.

Here are my lessons learned.

1) I would replace the spark plugs, wires, and crank sensor and that’s it. These engines are simple and usually free of any oil leaks. The Early 8.1L crank sensors have a habit of failing so definitely get a new one. All crank sensors from GM parts have been superceeded to the new design. Once you put the 8.1L engine in an old truck you will not be able to replace the sensor without removing the engine so do it now. The sensors are around $65 but I don’t have the part number for it.

2) The Topkick/Kodiac/Workhorse high mount A/C bracket part number is 12558927. An L29 7.4L bracket looks similar but the bolts do not line up in the head. You will definitely need the 12558927 for a clean A/C installation. If you use the stock Silverado A/C bracket you will have to hack up your frame and that is not good. I don’t have the GM part number for the alternator bracket but the Workhorse part number is W0003928. You will have to get this through a Workhorse dealer not a GM dealer, although many Workhorse dealers are GM dealers. I work for Navistar, Inc which owns Workhorse.

3) I DO NOT recommend using the donor vehicles harness, electronic throttle control and pedal assembly. The best $600 you can spend on this project would be to order a new harness from Howell Engine Development as reworking an original harness is time consuming and you will never get it to run right nor will the harness look like a clean fit. Reworking a Silverado’s bused electrical center in the harness is a major hassle. For $600 Howell will also program your ECM to eliminate the electronic throttle, turn off EGR (take the EGR valve off and throw it away then make a cover for the hole in the intake or find a plate from a 2003 or newer 8.1L that had the EGR deletion from the factory. EGR was discontinued in 2003), turn off torque management and add a hot tune if you want. They can add provisions into the harness and program the ECM for electric fans if you want to go that route. Mine is programmed to a 91 octane hot tune that is supposed to be good for 450 HP and 550 Lb ft of torque. When you call Howell speak with Rob. This is probably the harness you want if you are running a 4L80E http://www.howellefi.com/customer/ge...e-by-wire.html

4) If you go the route of the Howell harness and ditch the electronic throttle garbage use a 1996-2000 L29 7.4L mechanical throttle body as it bolts right on but you will need a throttle body spacer for clearance for the throttle cable arm to swing. On the other hand, if you want cruise control the electronic throttle system is the easiest way to get it.

5) I don’t recommend using the 8.1L exhaust manifolds as they will hit the frame on an older truck. Any big block header or exhaust manifold (396, 402, 454, etc) will fit the 8.1L.

6) I also do not recommend following the WyoTech instructors 8.1L swap recipe that can be found all over the internet in a PDF file. He did a lot of unnecessary work that he didn’t need to do.

7) You will need to rework the engine cross member to clear the oil pan. ORD’s HD engine cross member works great but I am not sure if it fits 67-72 4x4’s.

8) There is a small nub on the driver’s side of the engine that will need to be ground down just a tad so the engine mounts will bolt to the engine. At least that is what the saddle type engines mounts require. Not sure if the old style engine mounts will need this done or not. This will be an obvious thing you will see when you are installing your mounts.

9) One last simple thing, if you use an aftermarket tachometer you need to set it in 4 cylinder mode for it to read RPM’s correctly on distributorless GM engines.

Good luck. You will be thrilled once it is done!

Wow - great response - thank you!

I'm excited to get it this week.

I will probably be putting T400 & NP205 behind it.

Good call on crank sensor - mine went out in my '02 about 2 months after I bought my truck.

I'm using a DIY4x crossmember right now - not sure if it will fit - cross that bridge when I get there I guess!

I called Howell on Thursday last week - off recommendation of yours in one of your old post. They quoted $600 for harness +$200 to tune the computer.

Question I've been wondering - how did you plumb your AC to get from driver side top to passenger side firewall hook up?

Also wondering - if I'm using OEM '72 Factory tach - what do I need to do for that?

Thanks,

Ben



Wow, I am surprised they want an extra $200 over the cost of the harness. If I recall correctly, when I did mine the ECM programming was part of the harness cost. Maybe they changed their packaging or something.

A TH400 would work great behind an 8.1L but you may want to ask Howell if there is anything they can do to the harness in order to make the TH400 electric detent work more easily by tapping into the TPS signal. Not sure how you would get the TH400 electric detent work with an 8.1L otherwise.

As far as the A/C lines go, you’ll just have to have a hose shop custom make a set. My local Napa made mine.

There is a converter you can buy from MSD to make the factory tach work with a coil on plug engine. I ordered one and ended up sending it back once I figured out all I needed to do to my aftermarket tach was to set it on 4 cyl mode. This tach adapter should make your factory tach work with the 8.1L.

http://www.summitracing.com/parts/MSD-8913/

Chat with you later





So - ordered the two brackets I need:

$87.40 for the GM 12558927
$87.88 for the W0003928

Now -

Starting to get into this - and my 02 daily driver has been stumbling lately. Do you a code reader that you would recommend?


Any code reader should work to pull active codes. I am not sure if generic Autozone readers pull passive codes that do not trip a light though. A stumble could be low fuel pressure to failing plug wires or a coil. Hopefully, there is a code left behind to help steer you in the right direction.

Good to hear you got the brackets coming. I suspect both of these brackets will be discontinued though service parts before long.


Larry-

Two more questions:

1) What did you do with engine cross-member / oil pan clearance?

2) Do you know if I will need to alter anything or get different parts to get T400 to bolt up to 8.1?

Oh - and also - talked to a buddy who is old retired transmission mechanic. Asked him about the kick-down for the T400 - he said that the T400 has an electronic kick-down under the gas pedal. He said he would do the same setup -

So that when gas pedal is mashed, it hits the switch and kicks down tranny.

Thanks,

Ben

 

[modernbeat]

Larry, I've got some questions.

What is this part? W0000393 HOUSING ASM - PCM

Between what you listed and were quoted, there are three alternator bracket numbers. I've confirmed the 12559613 was used on the Savana. Are the two Workhorse numbers the same?

W0003928 Alternator bracket (Workhorse)
W8800110 Alternator bracket accepts a CS-144 alternator (now we know this is the alternator part number, not the bracket)
12559613 Alternator bracket (GM)

Are the engine cover and oil fill numbers the revised parts with the offset fill that does not foul the throttle cable?

 

[y5mgisi]

Insane thread Larry! Thank you! Wonder if i could run a 8.1 and a 6l80/6l90 trans???

 

[Larry]

Larry, I've got some questions.

What is this part? W0000393 HOUSING ASM - PCM

The Workhorse W0000393 ECM housing is the plastic piece the ECM snaps into.

These part numbers make up everything in this picture below that the ECM is mounted to. This is actually a Workhorse ECM mounting setup with provisions for an Allison TCM on top. I just used the TCM bracket as a cover per’se.

15764028 BRACKET - PCM
W0007848 BRACKET - TCM
15003790 x2 BRACKET - TCM legs

Between what you listed and were quoted, there are three alternator bracket numbers. I've confirmed the 12559613 was used on the Savana. Are the two Workhorse numbers the same?

W0003928 Alternator bracket (Workhorse)
W8800110 Alternator bracket accepts a CS-144 alternator
12559613 Alternator bracket (GM)

Figured the 12559613 was the G-van bracket, just not sure what is different between that one and the Workhorse W0003928. Would be interested in finding out someday. I see the confusion with the two alternator bracket part numbers. I goofed and provided the alternator part number instead of the alternator bracket . Whooops! Good catch! You’re correct the alternator bracket is W0003928. I fixed the post with the wrong part number.

Are the engine cover and oil fill numbers the revised parts with the offset fill that does not foul the throttle cable?

Yes, the following part numbers are for the later design engine cover with the s-shaped oil fill tube. Glad you brought that up.

2003-2007 Engine cover/oil fill

12574560 Engine Cover
12567370 Engine Cover Ball Stud
12562957 Engine Cover Bracket
12562958 x2 Engine Cover Bracket Stud

2000-2002 Engine cover/oil fill

12560199 Engine Cover
12562957 Engine Cover Bracket
12562958 x2 Engine Cover Bracket Stud

(2000-2002) 12560199 on left, (2003-2007) 12574560 on right

Good catch buddy!

 

[Larry]

Air Induction Pipe:

This one was a real PITA. For the first few years I used a stock Silverado air intake pipe which looked like poop. I had helped another guy (Blake H) on the 67-72chevytruck forum where he figured out a pretty nice concoction of Spectre air intake pieces to fit the 8.1L he swapped into his '86 2wd Crew Cab.

I cannot find the my Summit Racing invoice that lists the part numbers I used when I redid the air intake but here is Blake’s list. I pretty much copied all of Blake's pieces except I used a K&N filter.

Spectre Performance part numbers:
1 x 9781 4" Rubber 90 (throttle body)
1 x 9799 4" 90
1 x 9831 Filter housing
1 x 9729 4" 22 degree pipe that goes over the alternator.
1 x 990003 Adapter for the stock MAF Sensor
4 x 9771 4" coupler

All those part numbers cobbled together look something like this. I also used a Spectre bracket that connects to the alternator bracket to one of the large hose clamps to add support to the long pipe from flopping around but I cannot find the part number

Here is a novelty item one of my buddies made for me. A classic "Keep Your GM Truck All GM" decal modernized with L18 info. This is mounted on the radiator support

 

[y5mgisi]

Your a bad man for motivating people to do an 8.1 swap Larry. But i do love that sticker!

 

[Russell]

Got me convinced. Just bought my 8.1L

It's going into my 03 Tahoe

 

[y5mgisi]

that will be fun! Am about 80% sure I'm going to end up with one in my burb. Unless when the time comes I change my mind to a a nice vvt 6.0 or 6.2...

 

[80' 427]

Pretty happy with mine.

 

[y5mgisi]

I hear ya. Its a struggle because i love mine in my 12 so far. Its a 5.3 with VVT and AFM. Its got great torque off the line, great hp in the upper end, and has gotten up to 22.2 mpg on the highway so far. Its one of those things where, when they work good, they work good.

 

[biglos]

awesome thread larry! i saw your truck for the first time on EXPO way back in the day, ive been a fan of it since day one across all the forums lol. i always knew when i got around to my swap that you would be a great resource. appreciate the thread itll be a huge help for me in the future.