TOW RIG OVERHAUL! 2nd time... diesel swap

[GM Guy]

@Van Gui1d3r #838 the reason HD tow ratings were so ****** was they were rated not so much by chassis capacity and brakes, but more by what the transmissions were rated for, IIRC the NV4500 and 4L80E topped out at 19,000 combo.

As far as the truck, Have you considered leaving it long, and put a huge set of chrome fenders over the duals, put a gooseneck ball on it, and put diamond plate aluminum on top of the frame? there is an old square body C30 dually running around like that locally, the guy has a window sticker in the back that says "Daddy's Lambo" IDK if he put lambo doors on it or what.

As far as the 6.5L, I would take alot of what you hear with a grain of salt. I would love to know how many people on here bad mouthing 6.5Ls actually owned and used one, and if they did, was theirs in good shape, or was a POS when purchased and just went downhill from there?
We bought a 92 C3500 with a 350 and a 5 speed and it runs like garbage and has **** power, and even shittier fuel economy. Do I use this as a benchmark against all 350s? Nope. Not a chance. I know it has alot wrong with it, and I will reserve judgement till we get all the **** ironed out. I wont use a sick specimen to judge the healthy ones, and I wish people would do the same with the 6.5L.

To sum it up, 6.5Ls cant be neglected like a 12V Cummins. Neglect a 6.5L, and it will turn to ****. Plain and simple. You can work them hard, you just have to take care of them. They were ahead of their time with that requirement. with other diesels of the era, people could kinda get by treating them like garbage. Nowadays, try running a new diesel with a bad injector and see how it turns out.


My vote is buy that 750 dollar HD, fix what is wrong with the 6.5L, and run it for a while. If you like it, great, if not, its something to keep it rolling till you buy the powertrain and parts you want to use.

the biggest downfall of a 6.5L is people ignoring bad oil cooler lines, sticky t-stats, plugged radiators, poor lift pump delivery, and bad harmonic dampers. Address these issues, and it will be great.

Performance wise, the best thing to wake one up is a 4 inch exhaust and an A-Team Turbo. The factory turbo is quite restrictive, and builds high EGT. Not Good.

Here is a pick of my "lowly good for nothing 6.5L" she is bone stock and the engine has over 300,000 miles on her. Its a factory 5 speed, which IMO is good to have for a 6.5L, more power to the ground.

Total combo weight is 26,680 lbs. I remind you, bone stock. IIRC tow ratings for this truck was like 14,500 lbs or so. I drug this load down the state highway for 150 miles, so not exactly a back roads only trip.

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[shovelbill]

@Van Gui1d3r #838 the reason HD tow ratings were so ****** was they were rated not so much by chassis capacity and brakes, but more by what the transmissions were rated for, IIRC the NV4500 and 4L80E topped out at 19,000 combo.

As far as the truck, Have you considered leaving it long, and put a huge set of chrome fenders over the duals, put a gooseneck ball on it, and put diamond plate aluminum on top of the frame? there is an old square body C30 dually running around like that locally, the guy has a window sticker in the back that says "Daddy's Lambo" IDK if he put lambo doors on it or what.

As far as the 6.5L, I would take alot of what you hear with a grain of salt. I would love to know how many people on here bad mouthing 6.5Ls actually owned and used one, and if they did, was theirs in good shape, or was a POS when purchased and just went downhill from there?
We bought a 92 C3500 with a 350 and a 5 speed and it runs like garbage and has **** power, and even shittier fuel economy. Do I use this as a benchmark against all 350s? Nope. Not a chance. I know it has alot wrong with it, and I will reserve judgement till we get all the **** ironed out. I wont use a sick specimen to judge the healthy ones, and I wish people would do the same with the 6.5L.

To sum it up, 6.5Ls cant be neglected like a 12V Cummins. Neglect a 6.5L, and it will turn to ****. Plain and simple. You can work them hard, you just have to take care of them. They were ahead of their time with that requirement. with other diesels of the era, people could kinda get by treating them like garbage. Nowadays, try running a new diesel with a bad injector and see how it turns out.


My vote is buy that 750 dollar HD, fix what is wrong with the 6.5L, and run it for a while. If you like it, great, if not, its something to keep it rolling till you buy the powertrain and parts you want to use.

the biggest downfall of a 6.5L is people ignoring bad oil cooler lines, sticky t-stats, plugged radiators, poor lift pump delivery, and bad harmonic dampers. Address these issues, and it will be great.

Performance wise, the best thing to wake one up is a 4 inch exhaust and an A-Team Turbo. The factory turbo is quite restrictive, and builds high EGT. Not Good.

Here is a pick of my "lowly good for nothing 6.5L" she is bone stock and the engine has over 300,000 miles on her. Its a factory 5 speed, which IMO is good to have for a 6.5L, more power to the ground.

Total combo weight is 26,680 lbs. I remind you, bone stock. IIRC tow ratings for this truck was like 14,500 lbs or so. I drug this load down the state highway for 150 miles, so not exactly a back roads only trip.

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and don't run em hot.....they don't like heat or high EGT's......good on you man

 

[GM Guy]

also, as far as the Cat engines in the 2 tons, the 3116 is crap, and the 3126 is only marginally better. The 3208 Cat was not great in its early years, but give it 20 years of updates and a turbo, and they are very good engines. 636 cubes of v-8.

As much as I hate to say it, if you want I6, go with a 5.9L Cummins. If you cant bear the thought of it being out of a Dodge, find one out of a 90s Ford 2 ton. It will have a "gender neutral" SAE Bellhousing that most heavier Allisons will bolt to (but not too big of Allison, there is SAE 1 2 and 3, gotta have the right one)

But you are gonna keep the 6.5L anyways, right?

 

[GM Guy]

and don't run em hot.....they don't like heat or high EGT's......good on you man

Thanks!

Yep, a responsible 6.5er knows that 210 is danger zone on the coolant guage. On all of mine, the grille comes off and the radiator is removed and I give it a very thorough cleaning and fin straightening, and they all perform great.

I can go find photos, but that same truck was over Donner Pass in Cali last spring at over 20,000 lbs combo both ways! I had a load going in and coming out, and she handled it like a champ. For those who dont know, Donner Pass will bring about anything to its knees. Its a very long climb to the top, and while its not exactly an all-out horsepower test, its definitely a cooling system and powertrain test. It made the Diesel Power Magazine list for a reason.

Speaking of that list, my other 6.5L, speced identical, except 2 years older, conquered Vail Pass at over 21,000 lbs combo.

To say they have been good to me is an understatement.

 

[shovelbill]

Thanks!

Yep, a responsible 6.5er knows that 210 is danger zone on the coolant guage. On all of mine, the grille comes off and the radiator is removed and I give it a very thorough cleaning and fin straightening, and they all perform great.

I can go find photos, but that same truck was over Donner Pass in Cali last spring at over 20,000 lbs combo both ways! I had a load going in and coming out, and she handled it like a champ. For those who dont know, Donner Pass will bring about anything to its knees. Its a very long climb to the top, and while its not exactly an all-out horsepower test, its definitely a cooling system and powertrain test. It made the Diesel Power Magazine list for a reason.

Speaking of that list, my other 6.5L, speced identical, except 2 years older, conquered Vail Pass at over 21,000 lbs combo.

To say they have been good to me is an understatement.

eastbound is a ***** over Donner Pass as i recall....

an old friend in the towing industry told me tails of the Lincoln Highway he used to run.

 

[Van Gui1d3r #838]

@Van Gui1d3r #838 the reason HD tow ratings were so ****** was they were rated not so much by chassis capacity and brakes, but more by what the transmissions were rated for, IIRC the NV4500 and 4L80E topped out at 19,000 combo.

As far as the truck, Have you considered leaving it long, and put a huge set of chrome fenders over the duals, put a gooseneck ball on it, and put diamond plate aluminum on top of the frame? there is an old square body C30 dually running around like that locally, the guy has a window sticker in the back that says "Daddy's Lambo" IDK if he put lambo doors on it or what.

As far as the 6.5L, I would take alot of what you hear with a grain of salt. I would love to know how many people on here bad mouthing 6.5Ls actually owned and used one, and if they did, was theirs in good shape, or was a POS when purchased and just went downhill from there?
We bought a 92 C3500 with a 350 and a 5 speed and it runs like garbage and has **** power, and even shittier fuel economy. Do I use this as a benchmark against all 350s? Nope. Not a chance. I know it has alot wrong with it, and I will reserve judgement till we get all the **** ironed out. I wont use a sick specimen to judge the healthy ones, and I wish people would do the same with the 6.5L.

To sum it up, 6.5Ls cant be neglected like a 12V Cummins. Neglect a 6.5L, and it will turn to ****. Plain and simple. You can work them hard, you just have to take care of them. They were ahead of their time with that requirement. with other diesels of the era, people could kinda get by treating them like garbage. Nowadays, try running a new diesel with a bad injector and see how it turns out.


My vote is buy that 750 dollar HD, fix what is wrong with the 6.5L, and run it for a while. If you like it, great, if not, its something to keep it rolling till you buy the powertrain and parts you want to use.

the biggest downfall of a 6.5L is people ignoring bad oil cooler lines, sticky t-stats, plugged radiators, poor lift pump delivery, and bad harmonic dampers. Address these issues, and it will be great.

Performance wise, the best thing to wake one up is a 4 inch exhaust and an A-Team Turbo. The factory turbo is quite restrictive, and builds high EGT. Not Good.

Here is a pick of my "lowly good for nothing 6.5L" she is bone stock and the engine has over 300,000 miles on her. Its a factory 5 speed, which IMO is good to have for a 6.5L, more power to the ground.

Total combo weight is 26,680 lbs. I remind you, bone stock. IIRC tow ratings for this truck was like 14,500 lbs or so. I drug this load down the state highway for 150 miles, so not exactly a back roads only trip.

View media item 31192

he won't hold the 750 dollar truck for me. if he still has it when I have the rest of the dough, i'm buying it.

that sucks the truck is rated by the tranny.

and no, i'm not going to turn it into a mini rig... unless it gets a tandem axle conversion lol

I don't know about 6.5s myself. only have a few friends that have had them and didn't care for them. but I have no personal experience.

also, as far as the Cat engines in the 2 tons, the 3116 is crap, and the 3126 is only marginally better. The 3208 Cat was not great in its early years, but give it 20 years of updates and a turbo, and they are very good engines. 636 cubes of v-8.

As much as I hate to say it, if you want I6, go with a 5.9L Cummins. If you cant bear the thought of it being out of a Dodge, find one out of a 90s Ford 2 ton. It will have a "gender neutral" SAE Bellhousing that most heavier Allisons will bolt to (but not too big of Allison, there is SAE 1 2 and 3, gotta have the right one)

But you are gonna keep the 6.5L anyways, right?

I would keep the 6.5 till i'm ready to stuff a massive beast engine in there. I have considered the 5.9 but then I hear all the hype and it starts to sound too easy and done... my worst enemy is, "i don't want anything anyone else has" it sucks but leaves tons of room for creativity =D

 

[skylark]

@Van Gui1d3r #838

As far as the 6.5L, I would take alot of what you hear with a grain of salt. I would love to know how many people on here bad mouthing 6.5Ls actually owned and used one, and if they did, was theirs in good shape, or was a POS when purchased and just went downhill from there?
We bought a 92 C3500 with a 350 and a 5 speed and it runs like garbage and has **** power, and even shittier fuel economy. Do I use this as a benchmark against all 350s? Nope. Not a chance. I know it has alot wrong with it, and I will reserve judgement till we get all the **** ironed out. I wont use a sick specimen to judge the healthy ones, and I wish people would do the same with the 6.5L.

View media item 31192

Here is my 6.5 experience.
2000 k3500; bought it in reasonable shape with some neglect (steering) at 83k. I went through it from one end to the other. It lost a valve at 104k.

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1998 k3500; The original owner was on a road trip through Oregon from Canada. He lost a valve @79k. He literally had a book of every light bulb, oil change, car wash, fuel fill up, etc.

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1994 k3500; also lost a valve at 125k. I can't speak for itself maintenance history but it was well taken care of on the body and interior.

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The valves were all like this one. This one is from the 98. The valves were all the #3 exhaust.

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This is a 94 that I had that I bought with a bad pmd.

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[90halfton]

also, as far as the Cat engines in the 2 tons, the 3116 is crap, and the 3126 is only marginally better. The 3208 Cat was not great in its early years, but give it 20 years of updates and a turbo, and they are very good engines. 636 cubes of v-8.

As much as I hate to say it, if you want I6, go with a 5.9L Cummins. If you cant bear the thought of it being out of a Dodge, find one out of a 90s Ford 2 ton. It will have a "gender neutral" SAE Bellhousing that most heavier Allisons will bolt to (but not too big of Allison, there is SAE 1 2 and 3, gotta have the right one)

But you are gonna keep the 6.5L anyways, right?

I've put millions of miles and pto hours on 3116 and 3126 cats. Probably had a dozen of em. Never had a single problem with one of them, farmers collect em when they can get em cause they know they can rag on em and don't have to take care of em.
They're not powerhouses by any means, but they're efficient and reliable, though most of em need plugged in below 10° .

 

[GM Guy]

I've put millions of miles and pto hours on 3116 and 3126 cats. Probably had a dozen of em. Never had a single problem with one of them, farmers collect em when they can get em cause they know they can rag on em and don't have to take care of em.
They're not powerhouses by any means, but they're efficient and reliable, though most of em need plugged in below 10° .

Glad to hear you have good luck out of them, but our local tow truck operator friend is looking for one for his rollback, and the local heavy truck mechanic shop advises not to buy one, and they are Cat freaks that recommend most Cat engines.

 

[GM Guy]

@skylark what is the story on the brown one?

As far as the two duallys, I assume both were stock turbo and automatic with no EGT guage?

IMO that has alot to do with the failures. when the 6.5L runs out of power on a hill, the auto goes for the downshift and the motor screams away with high boost. As we know from the forums, the GM turbos have high drive pressures and are not very efficient and run high EGTs.

While we will never know, it would be interesting to see how an A-Team turbo would have affected the outcome.


But I have a few rules when buying a 6.5L. No low miles, and no automatics. It makes life easier.