Diesel Transplant For Chev 3500 HD 4X4

[peneumbra]

Due to the untimely death of the 6.5 GM diesel in my '94 3500 HD last winter, I've decided to do a transplant: a Cummins 12-valve P-pump engine.

The truck is unusual - GM produced the 3500 HD (15,000 GVW) in 2-wheel-drive, but if you wanted one in 4X4, the dealer would send it off to Tulsa Truck or some other converter, and you'd get a very stout truck with a Dana 70 front axle, and a Dana 80 rear. Most of these were sold to fire departments or the military.

Mine is in very good shape, no rust, with a 10-foot flatbed, 90-gallon fuel capacity, custom seats, all kinds of lights, etc etc. I was going to simply put in another 6.5, but I'm partial to the early Cummins, and I'm going to keep this truck for a long time. I'm told that there are adapter kits for the engine mounts and also for the bell housing (has a 4L80E transmission).

So we'll see what happens...:sombrero:

 

[XRrider]

Dieselconversion.com has motormounts and bellhousing adapters for all kinds of swaps. Sounds like a pretty neat truck.

 

[Colorado_Outback]

I have a 94 K3500 CCLB and would love to carry 90 gal of fuel. Any more info on how the tanks are setup?

 

[Marine]

Post up pics, I will follow for sure. I have a CR, and a 12 valve. Love my 12 so simple even I can figure it out. Also cppdiesel.com has some parts. Best of luck

 

[Bushcoat]

Awesome truck! Back in the day, a buddy had one that was a cube truck, 2wd obviously. Was a wreck, slid into a ditch and crushed most of the box. We pulled the box and shortened the wheelbase and put on a dually bed. I remember getting some strange looks and many conversations about it, we cut a second fuel door behind the wheel well for the rear tank, which threw some people off, then start looking around at the truck and it makes sense. I wanted to put a crew cab on there, but he didn't have a use for so much cab space.

 

[peneumbra]

@Coloradutback: The stock tank is, what, maybe 25 gallons. I had my welder fabricate one that mounts aft of the cab under the flatbed, and that holds almost 70 gallons. I had him put a large filler neck on it so I can fuel from the truck stop nozzles.

A good welder can make you a tank of almost any size. I was originally going to buy a used round tank off a Class 8 truck, but they're too large for this application.

 

[Larry]

Those are cool trucks and finding a unit already converted to 4x4 is pretty rare and a lucky score! Way back in 2001 or 2002 Burt Chevrolet in Denver had a few of them converted by Advance 4x4 out of SLC. All of them were 8.1L/4L80E with BorgWarner transfercases if I recall correctly. Below is a picture of the one that had a dump bed. The other 2 were still bare chassis cabs.

As you may know, I am not diesel fan but if you must have a diesel an old 12V is the one to have if you can tolerate the vibrations, smoke and noise. They're super easy to swap in as just about any farm boy with a welder and piece of fuel hose can make them run in just about anything. GM transmission adapters are easy to come by. You are a probably aware that where the challenge and expense is going to come in is purchasing a stand-alone transmission controller to run the 4L80E behind a fully mechanical engine. I believe your 94 has the electronic injection pump where the ECM controls the engine and transmission. 92/93 3500-HD's with mechanical 6.5L's adn 4L80E's had a stand-alone TCM that were basically the same old PCM used in old TBI vehicles but with a PROM set up to control trans shifting. If you need to go with a stand-alone TCM TCI sells a great kit (TCI EZ-TCU) for around $700. There are others on the market for about the same amount of money. I have a TCI EZ-TCU in one of my trucks running a 454 and 4L60E. It works great and easy to tune the shift schedule.

Anxious to see this project! Need pics!

 

[Colorado_Outback]

@Coloradutback: The stock tank is, what, maybe 25 gallons. I had my welder fabricate one that mounts aft of the cab under the flatbed, and that holds almost 70 gallons. I had him put a large filler neck on it so I can fuel from the truck stop nozzles.

A good welder can make you a tank of almost any size. I was originally going to buy a used round tank off a Class 8 truck, but they're too large for this application.

Mine has 34 gal stock, I just wasnt sure if the 1.5 trucks came with bigger duel tanks or something.

Ive built aluminum fuel cells and tanks in the past but I'm looking for a factory setup for this truck. Ill probably end up adding a 42gal Suburban tank.

 

[jeep-N-montero]

There are several detailed Cummins swaps over on the diesel pages, I love my 6.5 and the cost of ownership is hands down the cheapest you will find, but if it ever dies a Cummins will take its place.

 

[peneumbra]

I consider noise and smoke to be additional entertainment features (had to put a chrome vertical exhaust stack on her because the 6.5 put out a black cloud every time I pulled away from a stop). And there's a guy here who has figured out a motor mount that he says transmits very little vibration to the chassis. So we'll see.

There's really nothing available today that's like these trucks (in 4x4). Even the F-550/5500 trucks are not as stout, in my humble, but always correct, opinion. You'd have to go to something like an IH or a Freightliner 4x4 conversion...

 

[Larry]

You'd have to go to something like an IH or a Freightliner 4x4 conversion...

Nah, not even that. Modern day diesels are horrendously unreliable, especially the big ones in medium duty and heavy duty trucks. Anybody that says otherwise is lying or doesn't want to confess they have their dealer on speed dial and it doesn’t matter whose logo is on the steering wheel or what color the engine is under the hood. They're pretty much all a big bag of worms. I work for a diesel engine manufacturer and deal with them everyday, which is why I would not own a diesel (2007 or newer anyway). In fact, I’m dealing with a huge Forestry Service 4x4 brush truck at a dealer in TX now for repeat diesel engine aftertreatment issues that have been going on for 4 years on this one truck. If there has ever been a time for more gasoline engines in medium duty trucks it is now. If someone must have a diesel, make it an old one for sure.

 

[peneumbra]

@Larry: I hear this a lot from people who have had real problems with modern diesels. Personally, I really like the 356 cu inch straight eight that's in our 1947 Packard. Nine main bearings, and astonishingly smooth.

I just wish that there was a Packard dealer close to where we live...

 

[jeep-N-montero]

Nah, not even that. Modern day diesels are horrendously unreliable, especially the big ones in medium duty and heavy duty trucks. Anybody that says otherwise is lying or doesn't want to confess they have their dealer on speed dial and it doesn't matter whose logo is on the steering wheel or what color the engine is under the hood. They're pretty much all a big bag of worms. I work for a diesel engine manufacturer and deal with them everyday, which is why I would not own a diesel (2007 or newer anyway). In fact, I'm dealing with a huge Forestry Service 4x4 brush truck at a dealer in TX now for repeat diesel engine aftertreatment issues that have been going on for 4 years on this one truck. If there has ever been a time for more gasoline engines in medium duty trucks it is now. If someone must have a diesel, make it an old one for sure.

Sadly they only test the 2007 and newer diesels in most of the state, but at least that helps(forces) owners to keep them maintained despite their issues.

 

[chilliwak]

@Larry: I hear this a lot from people who have had real problems with modern diesels. Personally, I really like the 356 cu inch straight eight that's in our 1947 Packard. Nine main bearings, and astonishingly smooth.

I just wish that there was a Packard dealer close to where we live...

Or even better get a 6.5 optimiser that has been removed from a humvee for 3k and install that. Plethora bought one for his rig and is quite happy. All your 6.5 stuff should bolt right up. I hope this helps. Cheers, Chilli...

 

[peneumbra]

Found a Cummins 12 Valve For This Transplant

Found a 12 valve Cummins with a P-pump, under 100K miles, reportedly runs well, $3500.

Will be here early next week...