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Are There Any Chevy Straight 6 Engines Out There 4 A 83 Suburban Half Ton Turbo400?
- Thread starter blackandgold51
- Start date
I've always been a 6.2 fan and it would be my recommendation for this project based on cost and ease of swapping.......plus you can make them sound really good. I've owned a '90 K5 since 1994 that came from the factory with the 6.2, 700r4, 3.73's, and had 32" mud tires on it when I bought it with under 50k on the clock. Keep in mind I was a teenager back then and always had the gas pedal buried (insert 6.2 power joke here....) and consistently got 18-20 mpg. I remember being upset when the K5 was retired to a weekend play toy and purchased a '98 Toyota Tacoma to drive everyday. The Tacoma was a base model 4 cylinder, 5 speed, regular cab shortbed 4wd and got the same mileage as the K5.
I also had the opportunity to directly compare straight sixes to the 6.2 when working construction back then. The company I worked for had several C30 and F350 dually's with either the 292 or 300 straight sixes and manual trans that we drove everyday to the construction site. They also had a P30 box van with the 6.2 and automatic. That 6.2 felt way stronger than any of the old straight sixes.
Regarding swapping in a Cummins I really don't consider it cost effective. The $4-$5K cost to swap it over as estimated above would pay for a LOT of gas. Doing some quick math using the following numbers:
10,000 miles per year
Gas @ $2.50/gallon
Diesel @ $2.75/gallon
Increasing MPG from 10 MPG on gas to 20 MPG on diesel (doubling the MPG!)
These numbers equate to it taking almost 4 1/2 years of driving just to break even
I also had the opportunity to directly compare straight sixes to the 6.2 when working construction back then. The company I worked for had several C30 and F350 dually's with either the 292 or 300 straight sixes and manual trans that we drove everyday to the construction site. They also had a P30 box van with the 6.2 and automatic. That 6.2 felt way stronger than any of the old straight sixes.
Regarding swapping in a Cummins I really don't consider it cost effective. The $4-$5K cost to swap it over as estimated above would pay for a LOT of gas. Doing some quick math using the following numbers:
10,000 miles per year
Gas @ $2.50/gallon
Diesel @ $2.75/gallon
Increasing MPG from 10 MPG on gas to 20 MPG on diesel (doubling the MPG!)
These numbers equate to it taking almost 4 1/2 years of driving just to break even
blackandgold51
1/2 ton status
I wouldnt mind a Cummins however like you said it will be up there in funds range and to much stuff to install the diesel.
I wouldnt mind a 6.2 or straight 6. i just wonder how long the installation would be with the 6.2
blackandgold51
1/2 ton status
Thinking of 6.5 Diesel also.
The 6.2 has almost the same HP and torque as a pre-75 vintage 250 or 292 Chevy straight six,both make maximum torque around 1600 rpm....the diesel might "feel" more powerful due to it being fuel injected,and the higher compression ratio helps a lot,also 1 ton trucks usually have lower gear ratio's like 4:56's which would make any engine feel stronger than one in front of a truck with 3:08's or 3:73's.
I just went 110 miles in my '82 K2500 with a 6.2 / TH400--I had filled the tank to overflowing before I went that distance,and I drove it partly on highways and mostly rural back roads at speeds between 35-45 mph..it took almost 7 gallons to fill the tank back up,I calculated it is getting 15.9 mpg...
I see no real "savings" having a diesel,I have had many gas engines (a few were big blocks) do nearly as well on the same trip as far as mpg,and diesel fuel costs at least 30 cents more a gallon than gas...
Now the truck is going to need 2 new batteries (1 more than a gasser takes),and some new glow plugs at $10 a pop, (spark plugs are like $1.99),and if the starter craps out,that'll be over $100 easy,a gas engine starter can be had for $30 locally...the diesel takes more oil (7 qts, vs 5),and a fuel filter costs $20,and if the injector pump croaks ,a rebuilt will cost at least $400--you can buy a complete used 6.2 for that probably..all of these things and more have to be taken in consideration if you want a diesel swapped in..
The 6.2 probably is the simplest diesel to swap into a GM truck,since it was a factory option..but I'd reccomend buying a complete diesel donor truck if your going that route,because all the other pieces and trinkets you'll need will be a pain to hunt down at salvage yards..
The fact a lot of 6.2's crack the main bearing webs or the crankshaft,and heads gaskets seem to fail on them fairly commonly, would discourage me to put one in place of a gas engine..once the two I have decide to have a major malfunction,if I decide the trucks are worth fixing and keeping,I doubt I'd put another 6.2 back in..
As mentioned above the 6.2 is a very simple engine. That's actually a reason I have always kept it in my K5 after it was turned into a dedicated trail rig. It handles hills and off camber situations like fuel injection but none of the electronics. It basically needs a 12v power source to turn on the fuel relay and a fuel line and that is it.
I should also say that if you want a good driving and good fuel mileage setup with a 6.2 it really needs an overdrive transmission. Always been pleased with the 700r4 in my K5 with the low first gear and overdrive. The 6.2 benefits from lower gears for take off just like a gas engine and then the overdrive lets you have lower rpm's on the highway. I'm assuming the P30 box van mentioned above had a 4L80E as it was a 4 speed automatic with overdrive and pretty sure they wouldn't put a 700r4 in it.
I should also say that if you want a good driving and good fuel mileage setup with a 6.2 it really needs an overdrive transmission. Always been pleased with the 700r4 in my K5 with the low first gear and overdrive. The 6.2 benefits from lower gears for take off just like a gas engine and then the overdrive lets you have lower rpm's on the highway. I'm assuming the P30 box van mentioned above had a 4L80E as it was a 4 speed automatic with overdrive and pretty sure they wouldn't put a 700r4 in it.
I agree they do "go" better with a 5 speed manual or overdrive transmission,the lower first gear makes for better acceleration and overdrive lets it loaf on the highway..a straight six would also benefit a great deal with those two tranny options..
The first ride I took in my '85 K10 Suburban with a 6.2 and 700R4,3:73 gears ,it felt like it took off like a rocket off the line in comparison to my 3/4 ton pickup..
My truck with the TH400 and whatever gears it has (I assume they are 3:42's or 3:23's due to the fact it can hit 50+ mph in second gear,never had the diff cover off yet to look),and it having 265/75/16's on it,is not helping it attain its maximum mpg,it seems to be working hard to get it rolling and go uphill,but almost 16 mpg ain't all that bad considering its a 6200 lb ingot empty,with the wind resistance of a brick..
I'd rather have the beefier TH400 and live with a few less mpg,than have a 700R4 failing on me..(one in my Burb is dying,it loses reverse when hot and overdrive doesn't want to kick in)..the fact a TV cable failure will kill one in just a few miles is disturbing..
The most annoying time for me driving the pickup,is taking off from a dead stop,and going up a steep hill...it goes into second gear almost instantly and stays in second for quite a long distance,until it finally hits 35-40 mph--by then the tailgater behind me wants to pass,or starts honking..!...one hill in particular takes it nearly a 1/4 mile to finally get into third gear...
My '79 C-10 with a 250 would crest that hill doing 50 mph in a shorter distance..that truck was probably much lighter though..
Merging onto a busy highway is scary with the 6.2 ,I usually end up manually downshifting it and let it wind up to 3,000 rpm or so,otherwise it would want to stay in a higher gear and just slog along..other than it showing how under powered it is in those conditions,I'm not that disgusted with the diesel...but I do often wish it had a 350 or 454 in it..
I do like the fuel injection,no choke or cold weather carb problems,and no flooding if you go off camber with it..no doubt the 6.2 beats a carbed gas engine hands down in those respects..
But when it comes to working on them,I do not consider them an "easy" engine to fix-(a straight six wins that contest !)---the water pump design kinda sucks,the valve covers cant come off unless you take all the injector lines off,which may break,and are expensive and hard to find now--glow plugs do not last me more than a year or two,and are often a battle to get out of the heads..
I am very familiar with all the straight sixes and V8's up to 1987,but the 6.2 was a mystery engine when I got my first one,and I'm still unlikely to ever do a water pump ,injector pump,or timing chain replacement on one...I'll either send it out to be fixed,or yank it out..
I've put 3 starters in my 6.2,not a fun job,and it leaks oil intermittently from some mysterious spot on the rear of the drivers side head--might be a crack,its hard to tell..its about destroyed my driveway..
All told the 6.2 isn't a "bad" engine,neither is a 6.5,but they certainly do have their quirks..
The first ride I took in my '85 K10 Suburban with a 6.2 and 700R4,3:73 gears ,it felt like it took off like a rocket off the line in comparison to my 3/4 ton pickup..
My truck with the TH400 and whatever gears it has (I assume they are 3:42's or 3:23's due to the fact it can hit 50+ mph in second gear,never had the diff cover off yet to look),and it having 265/75/16's on it,is not helping it attain its maximum mpg,it seems to be working hard to get it rolling and go uphill,but almost 16 mpg ain't all that bad considering its a 6200 lb ingot empty,with the wind resistance of a brick..
I'd rather have the beefier TH400 and live with a few less mpg,than have a 700R4 failing on me..(one in my Burb is dying,it loses reverse when hot and overdrive doesn't want to kick in)..the fact a TV cable failure will kill one in just a few miles is disturbing..
The most annoying time for me driving the pickup,is taking off from a dead stop,and going up a steep hill...it goes into second gear almost instantly and stays in second for quite a long distance,until it finally hits 35-40 mph--by then the tailgater behind me wants to pass,or starts honking..!...one hill in particular takes it nearly a 1/4 mile to finally get into third gear...
My '79 C-10 with a 250 would crest that hill doing 50 mph in a shorter distance..that truck was probably much lighter though..
Merging onto a busy highway is scary with the 6.2 ,I usually end up manually downshifting it and let it wind up to 3,000 rpm or so,otherwise it would want to stay in a higher gear and just slog along..other than it showing how under powered it is in those conditions,I'm not that disgusted with the diesel...but I do often wish it had a 350 or 454 in it..
I do like the fuel injection,no choke or cold weather carb problems,and no flooding if you go off camber with it..no doubt the 6.2 beats a carbed gas engine hands down in those respects..
But when it comes to working on them,I do not consider them an "easy" engine to fix-(a straight six wins that contest !)---the water pump design kinda sucks,the valve covers cant come off unless you take all the injector lines off,which may break,and are expensive and hard to find now--glow plugs do not last me more than a year or two,and are often a battle to get out of the heads..
I am very familiar with all the straight sixes and V8's up to 1987,but the 6.2 was a mystery engine when I got my first one,and I'm still unlikely to ever do a water pump ,injector pump,or timing chain replacement on one...I'll either send it out to be fixed,or yank it out..
I've put 3 starters in my 6.2,not a fun job,and it leaks oil intermittently from some mysterious spot on the rear of the drivers side head--might be a crack,its hard to tell..its about destroyed my driveway..
All told the 6.2 isn't a "bad" engine,neither is a 6.5,but they certainly do have their quirks..
Diagnostics are pretty easy on a 6.2, but the process is different than what most people are used to on a gasser and probably the root of many of the issues that 6.2 haters mention. At my old house there was an old guy just outside of town that had a backwoods style mechanic shop and a yard full of old Chevy trucks to get parts off of. I think he could figure out what was wrong with a 350 V-8 by smelling it but was absolutely clueless with the 6.2. Remember stopping by to look for some used parts one day and it was cussing at a 6.2 powered truck that wouldn't run and he had been working on it for days. Took me about 2 minutes to figure out the root cause.....he had put a new fuel tank in it but didn't know you had to bleed the fuel system out.
I think later model 6.2's are a lot better in regards to reliability and power. Mine has somewhere around 120k on it and has had one water pump and one set of glow plugs replaced.
I think later model 6.2's are a lot better in regards to reliability and power. Mine has somewhere around 120k on it and has had one water pump and one set of glow plugs replaced.
The 6.2 in my pickup was a salvage yard refugee with supposedly 80K on it ,but I have no documentation..don't know what year it came from either,but looks "period correct" ,probably somewhere in the '80's vintage..that engine is makes a lot more diesel rattle than the one in the Burb,and both seem to have the injector pump timing marks lined up as factory..the pickup seems a bit peppier too,though the 700R4 and 3:73 gears in the Burb do make it take off faster off the line..
The glow plugs rot away more than they fail electrically on me--I've had several break the tabs off where the wires connect,or the hex portion flakes away so badly your lucky to get a socket hammered on them to get them to unscrew--I had to use a 9mm six point on more than one when a 3/8" one wouldn't grip it enough..
I'd be reluctant to attempt replacing a water pump on a 6.2,due to the design ,it'll be a good bet those long bolts that go thru the timing cover will be whittled down to nothing where they pass thru the castings and snap off,and you have to tear the engine down to the timing gears to re-seal that seperator plate--which is also noted for rotting thru and letting coolant get in the crankcase..
I doubt I could bend over long enough to do that job myself now..and I'd be tempted to pull the engine out instead--maybe leave it out too!..
The glow plugs rot away more than they fail electrically on me--I've had several break the tabs off where the wires connect,or the hex portion flakes away so badly your lucky to get a socket hammered on them to get them to unscrew--I had to use a 9mm six point on more than one when a 3/8" one wouldn't grip it enough..
I'd be reluctant to attempt replacing a water pump on a 6.2,due to the design ,it'll be a good bet those long bolts that go thru the timing cover will be whittled down to nothing where they pass thru the castings and snap off,and you have to tear the engine down to the timing gears to re-seal that seperator plate--which is also noted for rotting thru and letting coolant get in the crankcase..
I doubt I could bend over long enough to do that job myself now..and I'd be tempted to pull the engine out instead--maybe leave it out too!..
I'm pretty sure this has been beaten to death by now. Time-wise, a 6.2 swap will be about on par with swapping a carbureted small block. It's a one wire electrical system, and the sensors are compatible with the small block so no funky re-engineering is required to make it fit. You will need a fuel overflow line (which a carbureted rig will not already have). And you will need to reevaluate your gearing/tranny combination if you want fuel mileage. You'll never have much power, but it is definitely the cheapest way to get mileage shoe-horned into an ancient brick. A 6.2 is a $300 purchase, a 4BT is a $2500 purchase (not counting all the adapters and modifications required to make it fit).
@blackandgold51:
Mileage. Power. Pick one to prioritize and recognize that every single engine that has ever existed involves compromising these and other parameters. A modern big block will be better than what you have in every objectively measurable way, just as a modern small block will be better in almost every measurable way. And a cranky old diesel will be better in one or two ways. The question is how much time & money you're willing to spend chasing rainbows.
Mileage. Power. Pick one to prioritize and recognize that every single engine that has ever existed involves compromising these and other parameters. A modern big block will be better than what you have in every objectively measurable way, just as a modern small block will be better in almost every measurable way. And a cranky old diesel will be better in one or two ways. The question is how much time & money you're willing to spend chasing rainbows.
