Is the 6.5 a bad idea if I don't care about MPGs?

[urbex]

Short story - My main tow rig is a F350 dually, 7.3 turbo. Works great as a tow rig, but it's also WAY overdue for various maintenance issues...totally my fault, life got busy, etc etc. Realistically, I need to pull the motor and trans at this point, which means it will be out of commission for at least a few months (been down this road before, I know how long it will take _ME_ to do what I want to do to it, lol). I don't want to be without a truck for that length of time, so I've been looking at cheap trucks to fill the gap for a while.

This truck is strictly a tow rig/heavy hauler. I have 3 other vehicles, so there is no need to try to push it into daily driver use. I also have a lot of time and money into the Ford, so I have no intentions of replacing it...and I'm definitely not replacing a truck with a D60 solid front with an IFS truck, lol.

I drive this thing so infrequently that MPGs aren't even a mild concern to me...couldn't care less if I'm running in the single digits. I typically max out the Ford with 4K of slide in camper weight and 8K of trailer weight. I could deal with not going camping until it's back on the road again, as I doubt any 6.5 era truck is going to handle 5K+ pounds over the rear axle without modification, lol.

Been looking at 90's Chevys, hoping to find a cheap 2500/3500 with a Vortec 454, and found a couple really clean trucks with the 6.5 diesels in them. Everything I've found so far with Vortec 454s have either been 350K+ miles, completely thrashed trucks, or people asking stupid high money for them. Same with Ford 460/V10 trucks, and I'm not touching Dodges with the small block gas motors, nor am I paying 10 grand for a high mileage 12/24 valve Cummins. BTDT...the 318/360s are fine motors, but not with 8K behind them.

Also been reading about the cracked heads, cracked blocks, and PMD issues of the 6.5. So now I'm wondering if I should just keep looking for a clean 454 truck, or if these 6.5 trucks may be worth taking a look at?

 

[Bent77]

Having towed with both a 6.5T and a 7.3T there is a big power difference

The 6.5T isn’t awful for mileage until you tow
Biggest concern is that you are buying a use vehicle and potentially getting into a situation where it also needs service, so you don’t gain much in that scenario

 

[Russell]

The 6.5L is a light duty diesel engine. It is not designed to pull heavy loads, it is designed to get good gas mileage. If you take good care of the engine, you will get good service from them. I would consider the power to be very similar to a TBI 350, with slightly better torque for pulling. I think that a 6.5L would pull your camper and trailer just as well as your 7.3L does. Both trucks would be overloaded according to the GCVW ratings. A dually would handle the camper far better than a SWR truck would. Definitely get a long box and upgrade the rear suspension with air bags to better handle the weight.

Must check / do items on any 6.5L include:

1. Check the harmonic balancer and ensure that the rubber isolator isn't cracked or missing. Make sure the outer ring is square with the inner pulley. Failed balancers is a primary cause of crank failures.
2. If it hasn't been done already, relocate the PDM off the side of the injection pump and out towards the front of the engine compartment away from the radiator with a large heat sink to keep it cool. Heat kills the PDM and while the fuel running through the injection pump does a great job of cooling them while the engine is running, they get heat soaked shortly after the engine is shut down and the fuel stops flowing. This causes them to fail in short order. The grey PDMs are the newer revision and are better units to run.
3. Free flowing exhaust is a big deal with any diesel engine. Check for issues with clogged mufflers or catalytic converters.
4. Run Stanadyne fuel lubricant when operating the engine with ultra low sulfur diesel (ULSD). The sulfur was used as a lubricant and modern fuel must be supplemented or the injection pump will wear excessively fast.

I am convinced all 6.5L engines are cracked in the mains. I've never taken one apart and found one that was crack free. I've also never once seen an engine failure directly attributed to the cracking. I wouldn't worry about it. Same goes with the cracks between the valves on the heads. I've seen many engines with those cracks, but I've never actually seen an issue directly pertaining to them.

The newer the engine, the better the turbo. Early 6.2/6.5L engines were naturally aspirated and started turbocharging them in 93 with a GM-3. In 95 they went to the GM-5 then finally GM-7 turbochargers in 97. F VIN code engines did not have EGR systems installed in them which improved power somewhat due to the less restrictive intake manifold and better flowing exhaust manifolds. 97+ engines have oil sprayers on the bottom of the pistons which helps keep them cooler under heavy load, but they have a tendency to crack pistons as they are made smaller and lighter. I would avoid oil sprayed engines if I was given the choice.

My ideal year is 95. My last 6.5L diesel was a 95 2 door Tahoe with a 4l80e automatic transmission and it treated me very well until I swapped it out with an LB7 Duramax diesel engine with a ZF6-650 6 speed manual transmission.

 

[red EOD]

The original blocks are almost a guarantee to be cracked in the mains but they are also often rebuilt with those cracks. Not a roadside failure point.

For how long you are talking about using it there's really only a few things, harmonic balancer, get the PMD out of the engine bay, and keep the coolant temps below 210F. Not "oh it spiked to 220 then came right back down a few seconds later", 210 is max. GM cheaped out with the castings and once that temp is passed the head gaskets go, heads crack, and cylinders 7/8 get severely overheated (poor coolant flow back there).

There are upgrades to make the 6.2/6.5 a solid tow rig that keeps up with the others but I wouldn't worry about those for a short term truck. Getting rid of the stock turbo would be the best upgrade (they trap heat badly).

I've exceeded the weight your talking about with the naturally aspirated 6.2 numerous times.

 

[diesel4me]

I'd look for a truck with an 8.1 gas V8 ...or a Duramax...

 

[urbex]

Wow, I'm surprised that was coherent to anyone, lol. Took a couple hours to write that up, between work and meetings, with multiple thoughts merged into one post

Anyways, the big points for me with this is the short term aspect/not wanting to throw a bunch of time and money into building another truck, though it would be nice to have a truck that was more comfortable/easy to drive than the big Ford for times when I don't need to move 10K of weight...such as a small road trip to pick up an engine or axle. The Ford is nice, but it's a pain to get a big CCLB dually through some of these small towns, nothing about these interiors are comfortable, it's loud, the AC is dismal at best, no cruise control....So it may not necessarily be a buy and sell after a few months, but it's also not going to be a truck that I want to put a bunch of time and money into trying to get it on the same level as the Ford either. I'm also going into this knowing full well that these trucks aren't even in the same towing ball park as my truck, otherwise I'd just get another 7.3 Ford truck, lol.

My Ford isn't anywhere near stock any more. It left the factory as a 4x4 SRW N/A, and I built the DRW 4x4 turbo that Ford never made. I have upgraded injection pump, bigger injectors, open exhaust, added more suspension front and rear, bigger radiator/fan, head studs, more boost, etc..it's nowhere near the animal that left the factory.

I'm mainly looking at the Chevys at this point because I just think the overall driving experience is nicer in the Chevy. I had an '89 C3500 454 years back, and loved that truck, and also currently have a '95 Suburban that ultimately donated part of it's drivetrain to my K5..hell, I even thought about swapping the Ford drivetrain into a CCLB squarebody for a while too - get the power of the 7.3 in the nicer Chevy body

 

[6.2Blazer]

I always liked the 6.5 turbo trucks. My cousin bought a new '95 K3500 dually back in the day to replace his '93 454 TBI truck that pulled a backhoe on a trandem dually trailer almost daily. I'm sure that load was in the 20,000 lb. range and not including the steel flatbed, side tool boxes, and 100 gallon fuel tank in the bed. Remember he saying it pulled the trailer better than the 454 TBI and got twice the fuel mileage. I will say he spent very little time on the freeway and it is pretty flat around here, but it still got the job done. Also keep in mind at that time there were no Duramax's or Powerstrokes with 800+ ft-lbs. of torque. You could get a early model Dodge with a Cummins with under 200 HP and maybe 400 ft-lbs of torque, and another local had a newer F-350 7.3 with an aftermarket Hypermax turbo installed (believe Ford started offering factory turbo diesels around this time). I know the Chevy truck and 6.5 combination seemed like a better truck than either of the above. The early model Dodge trucks sucked to drive and the first gen Cummins were like driving a tractor around...they were always slow, they just didn't get any slower when hooking up a trailer.

 

[red EOD]

For your stated expectations, a 6.2/6.5 will work well. Plus you can build it up some later if you want for pretty cheap.

 

[campfire]

Also been reading about the cracked heads, cracked blocks, and PMD issues of the 6.5. So now I'm wondering if I should just keep looking for a clean 454 truck, or if these 6.5 trucks may be worth taking a look at?

I wouldn't worry about those things in the short term. The heads/block are either cracked or not cracked, but it's directly tied to overheating. If you don't overheat it, they should outlast the rest of the truck. If the previous owner has abused it, you should see signs (coolant in oil or tailpipe, or combustion gasses in the radiator).

The PMD is worth relocating if it's still in stock location. Keep in mind that '92 and '93 6.5 trucks still have the DB2 mechanical pump (no PMD to bother moving).

To answer your original question...no, a 6.5 is not a bad idea. It will fit the bill just fine (as would a 454). But I'm wondering why you need a fill-in truck for just a few months. You did say this thing is driven very infrequently. Is it not feasible to simply wait until you're done and skip the entire headache? Every vehicle comes with risk, and old trashed tow rigs are especially likely to have been neglected. I'd just wait it out and stick with the known good vehicle.

 

[urbex]

But I'm wondering why you need a fill-in truck for just a few months. You did say this thing is driven very infrequently. Is it not feasible to simply wait until you're done and skip the entire headache? Every vehicle comes with risk, and old trashed tow rigs are especially likely to have been neglected. I'd just wait it out and stick with the known good vehicle.

Need? No, of course not. But I don't WANT to go without boating or wheeling while this this thing is down either. I'll also be boned if I find I need something major in the meantime, like another block or transmission, or when we go up into the forest to get firewood. Last time I took a motor out of a rig, it was over a year before it went back in, because life happened. If it really came down to it, sure, I could make something work, or I could just buy another truck ahead of time and make my life easy, lol.

My plans include pulling the motor and trans, cleaning up the results of a few years worth of oil leaks, tearing the motor down and refreshing, refreshing the trans, rebuilding the turbo, replumbing all the oil and fuel lines, pulling the fuel tanks to fix broken senders/wonky filler hoses, pulling the flatbed to fix the half-assed mounts the PO hacked in, some wiring work, and other minor things here and there. I'm _expecting_ it to be down for 3 months or so, but it could take a year plus, once "well, since it's apart, might as well blah blah blah" kicks in too, lol.

I considered just using a trailer in the mean time, but my other vehicles are a '06 Cadillac STS that I'm not putting a trailer hitch on, a Samurai that weighs less than my smallest trailer...empty, and a K5 crawler on a 6" lift and 37s that also currently has the engine out and on the stand. That engine _should_ be ready to reinstall in a couple weeks, but I'm not wild about putting a heavy trailer behind a short wheelbase truck lifted that high. I also live out in the so called "middle of nowhere", so a rental is a big inconvenience for me.

So I started looking on Craigslist, and figured if I could find something for less than 3 grand, I would be OK dropping that amount for a temp truck.

 

[ZooMad75]

While I have nothing really constructive to add to this discussion I initially read the title as:
Is the 6.5 a bad idea if I don't care about MPH?

Depending on where you are with a 6.5 that could be a valid concern if there are hills or mountains involved.

Back to the oil burner discussion...

 

[campfire]

While I have nothing really constructive to add to this discussion I initially read the title as:
Is the 6.5 a bad idea if I don't care about MPH?

Depending on where you are with a 6.5 that could be a valid concern if there are hills or mountains involved.

Back to the oil burner discussion...

Hahaha!

 

[campfire]

Need? No, of course not. But I don't WANT to go without boating or wheeling while this this thing is down either. I'll also be boned if I find I need something major in the meantime, like another block or transmission, or when we go up into the forest to get firewood. Last time I took a motor out of a rig, it was over a year before it went back in, because life happened. If it really came down to it, sure, I could make something work, or I could just buy another truck ahead of time and make my life easy, lol.

If it's just a short-term convenience thing, a 3/4-ton with a 350, 5.3, or 6.0 might suffice. And that would drop the price some...

 

[urbex]

While I have nothing really constructive to add to this discussion I initially read the title as:
Is the 6.5 a bad idea if I don't care about MPH?

Depending on where you are with a 6.5 that could be a valid concern if there are hills or mountains involved.

Back to the oil burner discussion...

Ha! I actually went back to double check my OP to make sure I didn't flub that one!

There are hills and mountains here - Phoenix, AZ area, though I go throughout the state. Slowing down on the mountain grades is nothing new though...it's common even with the 7.3 when I'm pulling heavy. But never a lack of power, rather the EGTs start getting too high, and I have to get out of it just to keep those in check. If I wasn't dealing with EGTs, I have no doubt that this truck would pull 10K up the grades at 75mph without issue. I really need to get an intercooler in that truck....

If it's just a short-term convenience thing, a 3/4-ton with a 350, 5.3, or 6.0 might suffice. And that would drop the price some...

I've owned one truck with a small block in the past 20 years - the '05 Ram 1500, and that's just because I couldn't get the V10 in it without going to the SRT. All the rest of them have been big block gassers. Actually, that truck was a whole cluster due to my own lack of homework, and relying on what the sales guy at the dealer told me. I'm not entirely sure what happened there...all my life, ever since I was a teenager, I was big on doing my research before buying something. I'd often impulse buy toys, but I always knew what I was getting into before I did it, in that I knew exactly what I was looking for before buying...just would often buy the first one I looked at spec'ed the way I wanted.

In that case, I went in wanting a 3/4 or 1 ton quad cab, long bed, big block gas, 4x4 manual trans truck. Somehow I let the sales guy talk me into going home with a 1/2 ton, 2WD, short bed, auto trans truck, though I got the Hemi. Largely based on his claiming that Dodge no longer made a quad cab/long bed truck, and manuals were only available behind the diesels...which was entirely untrue, just exceptionally uncommon to find a truck spec'ed that way.

Like I said, I don't know WTF happened with me there

I learned a long time ago that buying the biggest engine available in a vehicle was generally the best idea. There never seemed to be a significant difference in MPGs between the smallest and biggest motors, but they always seemed under powered if I didn't get the big blocks, especially when I was using them for towing.

 

[imiceman44]

Something everyone is probably missing here and I did until I read further, you have the early 7.3 ford diesel with some upgrades and a turbo added.
Not to confuse with the 7.3 powerstroke that has the high power numbers and is great for towing.
The 7.3 is actually comparable to the 6.5 in power or capability

 

[urbex]

Something everyone is probably missing here and I did until I read further, you have the early 7.3 ford diesel with some upgrades and a turbo added.
Not to confuse with the 7.3 powerstroke that has the high power numbers and is great for towing.
The 7.3 is actually comparable to the 6.5 in power or capability

For some unknown reason, lots of people seem to think that the IDI motors are gutless turds, and Powerstrokes are some marvel of engineering that put down freight train like power numbers...which isn't at all accurate. Yes, the N/A IDI motors are comparatively gutless, as are just about all N/A diesels. But the Ford factory IDI turbo motors were rated at 190HP/388TQ, compared to the 1st gen 7.3 Powerstroke at 210HP/425TQ. Not exactly an earth shattering difference. The last 7.3 Powerstrokes did gain quite a bit, at 275HP/575HP.

7.3 IDI with the Banks kit? 267HP/503TQ. So just about splitting the different between 1st and last 7.3 Powerstrokes. Plus my IDI has been further modified past the kit that Banks ships. I've never put it on a dyno, but I know it pulls harder than my buddy's stock '01 F350 powerstroke, though he gets significantly better MPGs than I do. He consistently gets 5+mpg better than I do, with similar loads. His also burns cleaner, and is quieter, whereas mine has the old school diesel sound - like it's going to send every rod towards the moon

 

[Big Ray]

If you go 6.5, look for an Optimizer motor. They are becoming available as the military phases out the Humvee.

 

[urbex]

Isn't that basically a crate replacement motor? From what little I learned about those several years ago when I was looking at trucks, that would be something that would double or triple what my current planned budget is for this, just for the motor alone, lol. Even then, it sounded like it wasn't any more powerful than a factory shipped 6.5 in a pickup, just that it had the potential for more power due to a stronger block design?

Even then, this all started as a "oh hey, some of these diesel trucks are actually cheaper than the big block gas trucks...I wonder how they would work?" kind of thing, not that I went out intentionally looking for another diesel. Even when I bought the Ford, I was specifically looking for a big block gas/5 speed/crew cab/long bed/solid front axle 4x4/dually. I ended up with the diesel because because I found a rocking deal on it...basically could have made money easy in a week if I decided to part it out.

The solid front axle limited me to squarebodies in the GMs, and square crew cabs were already getting stupid expensive. Dodge didn't have a true crew cab until the 3rd gen 2002+ trucks, and they too were stupid expensive with the V10 or diesel engine, plus I wasn't wild about the front axles with the unitized bearing hubs.

So I was pretty much limited to 88+ Ford trucks, being that I wanted a 5 speed OD trans. Found my current truck that was the diesel, which I didn't really want then either. But I went to look at it anyways, figuring if I really didn't like it, it wouldn't be a big deal to swap a 460 in to it. Unfortunately, Ford didn't make a factory 4x4 dually until 1999, but it was an easy axle swap away. Found a PO already started it by putting a dually front axle in it, and I found a dually rear up the road for $100, and a set of dually wheels at the scrap yard in town for another $100. So all told, I ended up with the CCLB/4x4/dually I wanted for less than $2500....and found out later that I absolutely hate the Ford interiors...I just can't win

Maybe one day I'll end up swapping this drivetrain into a square crew cab, but I have so much else going on at the moment, that just buying another interim truck just seems like the best idea at the moment...I still need to tear the Samurai motor down again to try to track down the intermittent rattle I'm getting, I've got the rear end of my '59 International 2.5 ton torn apart to attempt to figure out why it's not shifting into high range (which also has a factory 140HP I6, no AC, and is an early prototype truck, so I don't want to start modifying it...otherwise I would just move this to priority one and use it as my back up truck), my bass boat needs to be redecked, my Cadillac needs a handful of gaskets replaced on the motor....I'm just too overloaded right now to take on yet another project truck.

 

[imiceman44]

Isn't that basically a crate replacement motor? From what little I learned about those several years ago when I was looking at trucks, that would be something that would double or triple what my current planned budget is for this, just for the motor alone, lol. Even then, it sounded like it wasn't any more powerful than a factory shipped 6.5 in a pickup, just that it had the potential for more power due to a stronger block design?

Even then, this all started as a "oh hey, some of these diesel trucks are actually cheaper than the big block gas trucks...I wonder how they would work?" kind of thing, not that I went out intentionally looking for another diesel. Even when I bought the Ford, I was specifically looking for a big block gas/5 speed/crew cab/long bed/solid front axle 4x4/dually. I ended up with the diesel because because I found a rocking deal on it...basically could have made money easy in a week if I decided to part it out.

The solid front axle limited me to squarebodies in the GMs, and square crew cabs were already getting stupid expensive. Dodge didn't have a true crew cab until the 3rd gen 2002+ trucks, and they too were stupid expensive with the V10 or diesel engine, plus I wasn't wild about the front axles with the unitized bearing hubs.

So I was pretty much limited to 88+ Ford trucks, being that I wanted a 5 speed OD trans. Found my current truck that was the diesel, which I didn't really want then either. But I went to look at it anyways, figuring if I really didn't like it, it wouldn't be a big deal to swap a 460 in to it. Unfortunately, Ford didn't make a factory 4x4 dually until 1999, but it was an easy axle swap away. Found a PO already started it by putting a dually front axle in it, and I found a dually rear up the road for $100, and a set of dually wheels at the scrap yard in town for another $100. So all told, I ended up with the CCLB/4x4/dually I wanted for less than $2500....and found out later that I absolutely hate the Ford interiors...I just can't win

Maybe one day I'll end up swapping this drivetrain into a square crew cab, but I have so much else going on at the moment, that just buying another interim truck just seems like the best idea at the moment...I still need to tear the Samurai motor down again to try to track down the intermittent rattle I'm getting, I've got the rear end of my '59 International 2.5 ton torn apart to attempt to figure out why it's not shifting into high range (which also has a factory 140HP I6, no AC, and is an early prototype truck, so I don't want to start modifying it...otherwise I would just move this to priority one and use it as my back up truck), my bass boat needs to be redecked, my Cadillac needs a handful of gaskets replaced on the motor....I'm just too overloaded right now to take on yet another project truck.

Yeah, that's how I ended up with 35 trucks

 

[urbex]

I'm up to eight at the moment, plus the bass boat, camper, and two trailers. Honestly, the only thing that has really tempered bringing home far more has been insurance, in that it seems silly for me to have individual liability only policies on everything, even things I virtually never drive, and to a lesser degree, registration. Plates on old vehicles are dirt cheap in Arizona, so that's less of an issue. Ends up costing something like $10-$15/year for plates on my old junk.

If I ever found a fleet insurance policy, where I would pay the same amount for just liability whether I have 5 vehicles or 50, I'd probably have something resembling a used car lot out back, lol. Be even better if I could leverage something like the deals that car dealers get, where they could slap a plate on any vehicle in the lot, but without having to run it all through a business here.