GMC / Chevy Project Big Betty, Cummins power in a weekend warrior

[SAVAGE]

I'm swapping a cummins into a 1988 GMC 1 ton crew cab dually. Im also converting it to single rear wheel. However i'm already halfway through this project so Ill help get you caught up. I had my eye on a old gmc that belonged to a rancher friend of mine. I asked if he would consider selling it to me and he told me that with all the work I had done over the years if I wanted the truck it I could have it.
This is how we found the old girl. 85,000 original miles, not a dent on her.
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We where lucky the trailer was big enough.
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Well we got it pushed in the shop and after a month of figuring out why she wouldn't run we found out the exhaust was plugged with a bunch of dead mice/mouse crap/nest crap. We saw the exhaust off and it fired right up. And of course we wheeled it...a little.

Next I put on some 265 75 r-16's, 4" lift, headers and painted a few things black for extra coolness... and wheeled it a little more.
View attachment 1110001652.jpgView attachment 1121001153.jpg
Then it sat in the yard for two years while I was preachin the good word. When I got back I was plagued with 454 TBI issues. I couldn't figure out why it never had much power, idled crappy, sputtered, stalled, and all that goes with it. I tinkered with it as time would allow trouble shooting everything I could think of. Turned out to be the little 1.5" piece of rubber hose in the sending unit between the fuel pump and the metal tube had a small crack relieving fuel back into the tank resulting in a significant loss of pressure to the throttle body. I was a fool and ruled out that possibility because it ran the same on both tanks. Well both sides had the same problem. Major pita.

 

[SAVAGE]

Then back in July right before my wedding I got a heck of a deal on a 1996 Dodge Cummins Manual 2500 4x4. 284,000 miles. Truck was beat all to hell from years of farm work but the motor was over hauled, blue printed, balanced and bored 40 over at 200,000 with the recipes to prove it. Also had a spankin new injection pump on it! The truck belonged to a good friend of mine that just wanted to get a good ol' 70's chevy 4x4. Well he found one he wanted for $1,200 bucks so I wrote him a check for 1,200 for the dodge and he went and got his chevy.

So I did what any other true american would do with a doner truck...[video=youtube_share;wMdZp8YjiGg]http://youtu.be/wMdZp8YjiGg[/video]
Well then it was time to start tearin down. I started with the GMC first so I could still rip around in the stinky Dodge.

Its always good to have a friend with a forklift.

Here how it sat waiting for someone to buy her.

I sold everything that goes with the motor, fuel lines, radiator, wiring, linkage, hoses, accessories ect.
Then it was time to start in on the Dodge.

I was sure excited to have that beast motor out. If I would have known the transmission oil was $25 a quart I would have tried not to spill it out of the tail housing when we pulled the motor. I also pulled out most of the engine wiring, a/c lines and other stuff for future use.
Well i'm tired, Ill post more on here tomorrow.

 

[jeep-N-montero]

I know there are several threads covering this swap over on dieselplace.com if you need some pictures or details. If I ever wear out the 6.5 in my tow rig I will be doing the same swap.

 

[Bart]

Very cool build. I would love to have that truck with a 12 valve Cummins in it. Subscribed.

 

[LT.]

I like it! Keep the updates coming.

LT.

 

[ricsrx]

why are you converting to single wheel?
I wish the parts would work on my 04 dodge, i would love it to be drw

 

[sixstringsteve]

very cool.

 

[SAVAGE]

why are you converting to single wheel?
I wish the parts would work on my 04 dodge, i would love it to be drw

Ill be using the truck as a trail rig/off roading/hunting/fishing/farm truck. I only tow about once a month anyway and when I do its only a tractor, horses, cows or something. Ill really never tow above 12,000 lbs, and with buying 6 tires at a time I couldnt think of a real reason to keep it dually. Oh and I prefer the look of a SRW truck over a DRW truck.

Thanks for the replies guys, Ill be posting more tonight!

 

[YROC FAB.]

Hell ya!!

Glad to see a thread on here. :thumbs:

 

[SAVAGE]

With the motor out it was time to fix all the oil leaks and get some nice new paint on it.


With the help of Kenworth Sales in Salina I was able to get all OEM Cummins seals for the motor... and for a lot cheaper than the parts stores in the area. I went ahead and did the front main, rear main, oil pan, vacuum pump kit, and the timing cover. I also had to replace the notorious leaky drain plug and gasket, got them from vatozone easy enough.


I used regular dupli color red engine enamel from napa for the motor (rated at 500 degrees). I was trying to match the new Cummins ISX Red color they are putting on the new motors. The baby crap tan (cummins beige) want cutting it for me ha ha. For the injection pump, turbo, head, manifolds, well all that black stuff is in high temp 2000 degree flat black engine paint.


Here it is with the valve covers and intake horn polished up. Oh and I also rattled the tranny and transfer case up in red.

 

[SAVAGE]

Well a really surprising challenge we had was fitting a crewcab long bed truck into my shop. The door wouldn't even close with the truck in longways, but side ways I had plenty of room. So with a engine hoist, and a lot of pushing we got it in there. Getting it out will be a fair bit harder, but maybe with my tranny twin sticked I can pull the ebrake and front dig the truck right around. Im kidding, ill probably just get a couple floor jacks and slide it.


Now it was time to start my DRW to SRW conversion. The dodge axle according to a bunch of forum jockeys was supposed to be a Dana 70/80 hybrid? Well just so you know it isnt, and im pretty sure there is no such thing as a dana 70/80 hybrid axle. Or I would at least love to see someone with actual proof of a hybrid axle. Mine is a Dana 70-2U with 3.5' axle tubes (they might have been 3 9/16"?). The biggest reason I'm keeping the Dodge axle is that it already has 4:10's and a limited slip differential. I think it is a detroit limited slip but i'm not sure, all I know it it was installed aftermarket.

Ok getting down to the good stuff. The dodge spring perches where like 4 inches wider than the chevy spring perches if I remember right. So I got my torch and was super careful and torched right along the weld and smacked them with a big hammer and they popped right off. I cleaned up the axle tube with a grinder and re-welded them back on in the correct position. I also gave them a couple few more degrees of angle to help compensate for the lift. My welds will never look like cory's but I thought I did ok.



Well heres how it all looks all bolted in. Yup I reused the old ubolts and mounting plate lol. They should will be fine until I eventually get some ubolts that put the nuts and plate on top of the spring pack giving slightly more ground clearance. But hey, its a budget build and new ubolts would be a luxury ha ha.



Then I moved on to my rear brakes. Both the Dodge and the Gm had those stupid sissy brake proportioning valves. So I did some research and found that brake hose that replaced the dodge load proportioning valve. Then a 30" piece of pre-made 3/16" brake line, an adapter from the chevy 5/16 make end to 3/16 male, and a 3/16 female coupler. I bent it into shape with a little hand tubing bender thing I got and I thought it turned out nicely.

 

[SAVAGE]

Alright now onto the front axle. I was really bambozzled over the whole dana 60 hubs. I found some for about $150 from amazon.com. Well I didnt really trust amazon with a order like that so It was easy enough to get Jegs to price match them. Well I got my order placed and nothing happened. For a few weeks actually and after getting pissed at Jegs for suprise back ordering me and never letting me know about it I cancelled and decided I had to figure something different out. I guess if its too good to be true it probably is lol.
Well I went ahead and decided I would look into machining my DRW 60 hubs into SRW hubs like in the dana 60 bible, but I was worried about the strength with it being on a part time street rig. So I asked my fellow web wheelers on Pirate4x4. http://www.pirate4x4.com/forum/chevy/1613610-turned-dana-60-dually-hub-strength.html
Well one thing is for sure, it is good to have a machinist/welder/fabricator for a friend. Cory took my hubs and cut off the outside flange. Then he turned them down on a lathe and trued up the mounting surface. You can correct me if im wrong here Cory. Then he made some killer 3/8 steel rings for the wheel to mount to for added strength. After seeing his TIG welds i'm pretty confident that they will hold up to everything I will put them through. I have even been thinking if they really did break what would happen? A crack on one side starting with the mounting ears and working its way to the 3/8 ring and to the other ears. On the freeway it most likely be a bad death wobble. At the very worst the wheel and hub would fall off. So big deal. If you have ever had tire work done at BIG O TIRES in richfield utah you have most likely had your tire fall off on the freeway anyway. Me and my dad have had it happen to us 3 times.
Anyway heres some dana 60 porn.



Annd here is the wheel studs I used, Cory scored us both a set for free$$$$



If you use these you need a 19/32" drill bit. Just go to town, look in every store, not find one, and when you do find out it costs $37. Or you can use the one your machinist buddy made out of a 5/8" drill bit. He actually knows what he's doing and went ahead and drilled out my hubs on his drill press for me. Well after he drilled them I went home and got my favorite 8lb slegde and started driving some studs home. It took a while but I got it done.



And heres what they look like installed.


Well goodnight yall, see ya tomorrow

 

[YROC FAB.]

Do you need extra locking hubs? I have my stock take offs.

 

[SAVAGE]

Do you need extra locking hubs? I have my stock take offs.

Hmmm if they are the metal warn ones. I really dont need them but if they are better than my plastic ones I guess I could have some spares. Bring them over friday and Ill look at em.

 

[SAVAGE]

Ok well now here is the really technical cummins swapping conversion adapting I went through.
I pulled out this NP241 out of the Dodge. It has a 29 spline female input and a slip yolk output. I chose not to use this transfer case mainly because it is driver side drop. This can be used easy enough, all you have to do is swap in a reverse cut high pinion ford dana 60. Well those are spendy, you would be lucky to find one for $1,200, and then you might look at 2 or 3 hundred in seals, gears, and bearings. My chevy dana 60 has low miles and the right gears in it already so I really didnt want to swap it out.


Another option to do would be to find a passenger side drop Dodge NP205 with a 29 spline input. These came in the dodge cummins manual five speed 4x4(duh) 2500 and 3500 from 1989-1993. I thought I could find one pretty easy, but I thought wrong. The best deal I found was my junkyard found me one in texas for $550+$200 shipping.
Yet another option was to use my dodge np241 as a doubler bolting to my chevy np205 with the 32 spline input. Basically I use the front half of my np241 (the chunk with the planatarys) and bolt it to my nv4500 since they both are 29 spline. Then you insert the coustom shaft into the rear of the planetary and it goes right into the np205. And there is some cutting and re welding to a new adapter plate to mount the two together. At around 600 bucks I had my heart set on this option from Trail Tech Fabrication. What wouldn't be awesome about a 123:1 crawl ratio?:greg: So I got my fist full of dollars and called them up only to have my heart broken. Because the np241 was a heavy duty version made specifically for the cummins motor I would have to had send in my midshaft and some other parts so they could custom machine something that would work for my. Well custom means $$$$$$$$$$$$ so I had to shy away from that option.
But what they did offer me was a way to simple convert my NP205 to be a 29 spline input. Since my 205 was a 32 spline the input bearings are already the same size and no machining is required. I ended up ordering a complete kit to adapt my NP205 to my NV4500 and it only cost me $605.
Here is the complete kit. It comes with everything you need. The infinatly clockable adapter, inputshaft/gear, 29 spline coupler, complete seal kit for the 205, gaskets fot the adapter and some stickers.

The adapter is a seriously solid chunk of beautifully machined steel. The pieces lock together so you can weld it without worrying about it not being aligned or something.

Here is the coupler and gear which I am very happy with. Added bonus is that it is the same coupler and gear that are used in the dodge trucks anyway incase I ever need to replace one of them.

I highly recommend them! Trail Tech Fabrication, Mike is the guy I dealt with, he answered all my questions and responded to them very quickly. Oh and free shipping!!!


Im still making the twin stick shift levers at this point, once I get them done Ill throw up some pics of the transfer case in the truck.

 

[SAVAGE]

Alright I just barley got the motor all bolted in about a week ago. I started about 3 weeks ago. I was really envious of the quad motor mounts that are sold by Auto World and thats what I was kinda basing my mounts off>> (http://www.cumminsdieselrepowers.com/Instructions/imag016A.html) I liked the design and everything but again im a tightwad so I made a order to Summit Racing and got 4 Anchor 2710 motor mounts, my Dana 60 lunchboxer, and two 25ft rolls of fuel hose, one 3/8" for supply and one 5/16" for return.


So with a few hundered test fits of the motor and tranny I started "fabricating." I had lots of steel plate and lots of heavy 4x4 steel tube. I origionally planned to build two crossmembers where you only see one. However I noticed that if I ever need to pull the motor in the future it would be a lot easier without the back one so the cummins oil pan will clear. After a bunch of welding, notching, and more welding these motor mounts are solid!


Here Is a view from the driver and passenger side wheel well.


And here it is all bolted in and ready to rock and roll.


And here we are rocking and rolling.
[video=youtube_share;cg_kT4fYUTI]http://youtu.be/cg_kT4fYUTI[/video]

 

[SAVAGE]

And thats about where I'm at. Right now I'm working on transfer case shift levers, wiring, and rounding up some money for paint and primer. Dont worry though Ill keep you all updated and if you have any questions at all Ill do my best to answer them.

 

[Bart]

Great work. Always nice when it fires the first time.

 

[sawtooth4x4]

nice work!

 

[sixstringsteve]

Looking good. That motor sounds strong.