1994 GMC Cummins Converison

[1GMC4x4]

Well it's time to move on to that next stage for my truck and that means More Power!.... And better Fuel economy..

I got this donor truck for a steal and im starting to gather the rest of the parts for the conversion.

To start:
I have a 1994 GMC 1/2T that I did a SAS earlier. 350/4L60e/np241/44/14b
http://www.pirate4x4.com/forum/showt...003&highlight=

The donor truck:
1996 Dodge 2500 12V diesel/NV4500/Np241C




The Plan:
Use Auto World MT mounts http://autoworldmt.com/

I should be able to use all the dodge components like the AC compressor and Alternator since I have clearance with the straight axle. I will need to get a Conversion for the alternator to make the Dodge a single wire unit like Chevys.
I plan to us the NV4500 and back it with an early chevy NP241 Passenger side drop transfercase. (I may decide to go with a NP205).

I'll type up a better game plan as things start to progress but feel free to chime in with any recommendations and pointers as this is my first Diesel.

The end game for this is to have a dual tank setup to run Straight Vegetable Oil.

My cherry is officially popped.

[MaxPF]

Originally Posted by 1GMC4x4

I'll type up a better game plan as things start to progress but feel free to chime in with any recommendations and pointers as this is my first Diesel.

I will give you my recommendation: Start with a 3/4 ton truck, and run a D60 front. The Cummins weighs nearly double what your 350 weighs. The 1/2 ton frame might be OK, but a 3/4 or 1 ton is better. The D44 is going to eat ball joints - I speak from experience.

[Aisin]

Yep. Motor weighs 1000+ pounds. Your ball joints will say fuck you.

[geo in a K5]

Finally the cummins swap

Since your using this truck mainly as your tow rig you should be fine with the d44 with some trussing to keep the housing straight but I do agree with maxpf that your ball joints will suffer.

I would run it with the d44 until you either find a Ford d60( king pin or 05+ SD 60) or rebuild that dodge d60 but get rid of the cad system and replace everything from the C's out with Ford stuff and you would have a plenty stout axle. Granted it would still be a bj axle but those ball joints were designed with the weight of the cummins in mind.
Dodge axle mods:
/forum/dodge/1000570-my-hub-conversion-story-lots-pics.html

http://www.pirate4x4.com/forum/showt...0+ford+kingpin

[geo in a K5]

Actually i just went through your build thread and saw that you are using a chevy lp d44..... in that case just stick a good ole GM dana 60 under there and call it good.

[MaxPF]

Originally Posted by geo in a K5

Since your using this truck mainly as your tow rig you should be fine with the d44 with some trussing to keep the housing straight but I do agree with maxpf that your ball joints will suffer

The housing and tubes will be fine, unless he plans on jumping it. It's the ball joints that are the problem - hopefully he enjoys changing them. If he's planning on using this for a tow rig, he really blew it by starting with a 1/2 ton.

[1GMC4x4]

I'm not totally sure about this but talking with the folks at AutoWorld I asked them that very question (if my frame would be up to the task) and they told me that that year there was no difference in the frame from 1/2T-3/4T. All the upgrades were in the suspension and drivetrain.
If it makes a difference its a "heavy half ton"

Either way the truck is what it is. I plan to run the 44 and see how bad it gets and cross that bridge when and if the time comes to upgrade to a D60.

[jps4jeep]

Frame would not be a concern of mine. The information about the frames is accurate, but to give an example, all 1/2 ton GM trucks of those vintage (except the 1500 suburban) were available with a 6.5 diesel and the weight of the motors are somewhat close. I have a co-worker with a 2 door tahoe with a 6.5 and it is the exact same frame as in my 98 1500. Some people argue power and torque effecting those frames, but those trucks were available with every motor from a 4.3 to a 454 cid and diesels, not a concern in my mind.

As stated the D44 ball jonts would be a concern, I would not just say get King Pins, but there are better options, if your swapping the dodge's entire drivetrain over. why not include the t-case and use the front axle, while not ideal, it would fair better.

[MaxPF]

Originally Posted by jps4jeep

Frame would not be a concern of mine. The information about the frames is accurate, but to give an example, all 1/2 ton GM trucks of those vintage (except the 1500 suburban) were available with a 6.5 diesel and the weight of the motors are somewhat close. I have a co-worker with a 2 door tahoe with a 6.5 and it is the exact same frame as in my 98 1500. Some people argue power and torque effecting those frames, but those trucks were available with every motor from a 4.3 to a 454 cid and diesels, not a concern in my mind.

The 6.5 isn't nearly as heavy as a Cummins. It was specifically made lightweight to enable it to be put in 1/2 tons. According to AM General, their Optimizer 6500, which has more metal in it than any GM 6.5, weighs 756lbs
ready to run. A Cummins weighs 1050-1300lbs, depending on configuration and accessories. Figure 1100 for a typical Dodge setup. That's a 350lb difference, which isn't "somewhat close".

As stated the D44 ball jonts would be a concern, I would not just say get King Pins, but there are better options, if your swapping the dodge's entire drivetrain over. why not include the t-case and use the front axle, while not ideal, it would fair better.

So, a Dodge ball joint front 60 is better than a kingpin 60? Do yourself a favor and go back over to the Jeep noob forum.

[jps4jeep]

On the first point, I was under the impression that a fully dressed 6.5 was in the area of 900-1000# and that the dodge 12 valve was 1100#. I was not aware that a dodge 12 valve weighed as much as 1300lbs.

As for the axle I never typed the dodge ball joint 60 was the best option. A king pin axle would ideally be a better choice, I was typing that the dodge 60 that came in the truck he purchased would be a better option than the D44 he currently runs.

[georgiaboy2500HD]

that white cummins looks like its a 4x4... why not use the front d60 from that? it would be be alot better than that 44 anyday and its driverside drop...

[MaxPF]

Originally Posted by jps4jeep

On the first point, I was under the impression that a fully dressed 6.5 was in the area of 900-1000# and that the dodge 12 valve was 1100#. I was not aware that a dodge 12 valve weighed as much as 1300lbs.

Had you actually read AND comprehended my above post, you would see that I said a B series Cummins can weigh AS MUCH AS 1300lbs, and that a TYPICAL DODGE SETUP WEIGHS ABOUT 1100lbs. Second, you were under the wrong impression about the weight of a 6.5. Since you didn't know what you were talking about, you gave bad advice. See how that works?

As for the axle I never typed the dodge ball joint 60 was the best option. A king pin axle would ideally be a better choice, I was typing that the dodge 60 that came in the truck he purchased would be a better option than the D44 he currently runs.

You said "I would not just say get King Pins, but there are better options,", which implied that the later Dodge 60 is a better option than a king pin 60. Perhaps you meant "there are other options"?If so, you should have said that.

Apparently reading comprehension and communication skills are a dying art.

[rockbuggy84]

I personally wouldnt worry too much about the 44 bj issue until a problem presents itself. Take into account that adding a heavy bumper and a winch on the older factory rigs with 44s was more than common and balljoints didnt just fail everyday.

Oh and look at the size of the bj on the cummins 60 and then compare it to the 44, hardly a difference.

[1GMC4x4]

That was my argument before.
People install 200-300lb+ bumpers and when you take leverage into account its way more than the extra 400lbs the cummins weighs.

But moving past the ball joint issue which I will take care of if the issue arises. I've read that I can use my factory gas tank by removing the gas and screen on the pickup and changing out the filler neck. Is this really all thats involved? I've heard some people install inline pumps instead of using the in-tank pump. Is that just when your requiring more fuel for more power?

[trkklr77]

Originally Posted by rockbuggy84

I personally wouldnt worry too much about the 44 bj issue until a problem presents itself. Take into account that adding a heavy bumper and a winch on the older factory rigs with 44s was more than common and balljoints didnt just fail everyday.

Oh and look at the size of the bj on the cummins 60 and then compare it to the 44, hardly a difference.

and seeing as how i replace modern balljoints weekly in dodge and ford trucks and not a single set of kingpins in 2.5 years also says somthing about modern bj setups.

[K5runner@hotmail.com]

I would worry about frame. GM did design the frames with all of the above engines in mind, but the frame was NOT designed to be in a leaf spring configuration. We had our 92' 1500 crack (and start to bend in the middle). All we had was a 454 in it. about 400 less. (~800 vs. ~1200 from what I know). We ended up boxing the frame (the entire length) over the existing boxing.

The frame is not designed for the loads that the leaf spring brackets put on it. What happens is the shackle bracket pushes up on the inside and the body mount pushes down on the out side. The front section is boxed (stock) because of all this the frame cracks right in front of the shackle mount. We added a crossmember over the tranny to hep with the frame twist.

[K5runner@hotmail.com]

http://www.pirate4x4.com/forum/showt...highlight=vach

Some pics of what we did. BTW its in a ForSale add that has been sold.

[440-fide Ramcharger]

Go see Rod at San Jose generator for that alt conversion. 40 San Jose Ave 408 293 2200. Tell him I sent you.

Mark

[bggrnchvy]

Originally Posted by 1GMC4x4

I'm not totally sure about this but talking with the folks at AutoWorld I asked them that very question (if my frame would be up to the task) and they told me that that year there was no difference in the frame from 1/2T-3/4T. All the upgrades were in the suspension and drivetrain.
If it makes a difference its a "heavy half ton"

Heavy half is just a bigger rear axle (AAM9.5), different leaf packs and a higher rated torsion bar set.

The 1/2t and 7200gvwr 3/4 tons are the same more or less. F44 'heavy half' 1/2ts and 7200 gvwr 3/4t's are the same spec.

8 lug 8600gvwr 3/4 ton's have a different, thicker frame with a slightly different profile on the front boxed section as well as a completely different drivetrain (short of the same 241, just with a 32 spl input).

[THEWHITEZOMBIE]

About time

[1GMC4x4]

Originally Posted by THEWHITEZOMBIE

About time

Fuck ya

Originally Posted by 440-fide Ramcharger

Go see Rod at San Jose generator for that alt conversion. 40 San Jose Ave 408 293 2200. Tell him I sent you.

Mark

My current alternator is from there. He definitely knows his stuff.

Originally Posted by K5runner@hotmail.com

I would worry about frame. GM did design the frames with all of the above engines in mind, but the frame was NOT designed to be in a leaf spring configuration. We had our 92' 1500 crack (and start to bend in the middle). All we had was a 454 in it. about 400 less. (~800 vs. ~1200 from what I know). We ended up boxing the frame (the entire length) over the existing boxing.

The frame is not designed for the loads that the leaf spring brackets put on it. What happens is the shackle bracket pushes up on the inside and the body mount pushes down on the out side. The front section is boxed (stock) because of all this the frame cracks right in front of the shackle mount. We added a crossmember over the tranny to hep with the frame twist.

From the pics I assume he jumped it. Mine likes to stay on tera firma. But I am adding a stronger engine crossmember and tranny/transfer case crossmember.

[K5runner@hotmail.com]

Originally Posted by 1GMC4x4

From the pics I assume he jumped it. Mine likes to stay on tera firma. But I am adding a stronger engine crossmember and tranny/transfer case crossmember.

You assumed wrong. This was the Mag truck that ORU build. It was a pavement powder with a 305 POS, and the frame was cracked when we got it. We bought a different straight frame and redid the whole thing before we were able to take it off road.
http://www.offroadunlimited.com/orus...ails.asp?id=43

[440-fide Ramcharger]

[QUOTE=1GMC4x4;14388264]

My current alternator is from there. He definitely knows his stuff.

QUOTE]

[THEWHITEZOMBIE]

Originally Posted by 440-fide Ramcharger

Go see Rod at San Jose generator for that alt conversion. 40 San Jose Ave 408 293 2200. Tell him I sent you.

Mark

I had him rebuild my starter for the Highboy, just said i knew Mark and Rob haha worked like a champ

[Y5mgisi]

Subscribed. Personally, i think the frame will be ok so long as you arent an idiot.