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1996 Suburban Cummins 12V Conversion Build up with pics

321K views 279 replies 56 participants last post by  dixiepc 
#1 · (Edited)
We are almost done with a 12V Cummins into a K2500 Suburban 4x4.

The Suburban is a 1996 GMC and was a 454 Vortec truck when we started. We used the original transmission 4L80E with a controller. We ended up putting a 1" body lift on to make life easier although it wasn't required.

This entire swap was done without discharging the Air Conditioning.

Most all of the swap parts were from Autoworldmt.com - they were great during this entire swap. They supplied the motor mounts, trans controller, A/C mount, alternator mount, transmission adapter and tachometer drive.

Transmission was move back 3" to accommodate the longer Cummins engine. We moved the transmission coolers to underneath the truck, we used the factory cooler and a cooler from Derale with a fan on it.


Here is the engine, it is from a 1993 Dodge:



Another engine shot:



This shows what we had to cut from the core support to use a 1994-1998 Dodge Truck Intercooler, we did end up cutting more than what is shown but not much:




Here the engine is sitting on the mounts in the truck:



Another in truck shot:



Here is a clearance picture with the stock IFS and the Cummins Oil Pan. It doesn't touch but it's close. We have to countersink a few of the bolts:



Originally we tried to use the stock dodge manifold but ran into clearance issues since this Suburban has dual heat and A/C:






We ended up using a 2003 Dodge Manifold which is a lower mount and cleared everything:



 
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#2 ·
More Pics

Here is a shot of the engine with everything wired (but the wires aren't loomed back up yet), most of the intercooler piping and the radiator hoses are done:



Here is is with the wiring more complete and this was after we drove it:




Here it is with the intercooler, radiator and condenser installed:



Close up shot of the driver side intercooler:




Here is the truck after today:

 
#3 ·
Looking real good. Thanks for posting the pics. Hows the trans controller working? Is the hood going to hit the A/C compressor? How long did it take to get the parts from Autoworld, I might be using there mounts for my 93 chevy dually.
 
#5 ·
Autoworld was very quick with getting stuff to me. They had most everything in stock and the item they didn't have in stock (I can't remember what it was now) only took a week for them to fabricate up.

The hood did hit the compressor and I could have made the stock hood work I think but instead I just put a cowl hood on it and still had to trim for the A/C nipple and the dryer next to it.
 
#8 ·
The parking light has 2 bulbs, both do the same thing, I was going to eliminate the backside of one side and seal it up with some sheet metal or something... Or if I can find some LED parking lights, I will swap them out for those as they would be much thinner.
 
#12 · (Edited)
Thanks! I did forget to mention a few things:

The intercooler we got was new aftermarket and was wider at the top (near the headlights) than a stock one. We have to have it cut and plated to clear the headlights, I have seen a stock one work with just removing the Dodge brackets but this aftermarket one was different. Here is a pic of the cooler we received:




Here is a pic where you can see it with the brackets cut off and the top plated. It cost about $175 to do have this plated at a hot rod shop and they also pressure checked it after it was done:

 
#17 ·
I've only driven it 100 miles or so, still working bugs out like the power steering return lines weren't totally tight so they leaked a tad, little things like that.

The controller I went with was the Simple Shift:

http://www.powertraincontrolsolutions.com/simpleshift.php

I like how it is easy to adjust and seems to work very well. The only issue I have is it shifts out of first rather quickly but I am a little apprehensive to 'wood it' off of the line. I am not sure what the instant torque might do to stuff. I know the 454 had more torque but it came on more gradually and at a higher RPM.
 
#20 ·
man, that is one sweet build. Just what I want to do to my 97 burb. I've found a 95 donor motor/tranny/tcase and ALL related components that have 84K miles. Still scrounging odds and ends, and trying to decide which axles to go with. If you don't mind I would like to ask alot of questions once I get more into my project.
My son and I are about to finish up on his.....a 93 S10 with a 1st gen 5.9
 
#27 ·
I was originally told that I would need to cut a notch in the torsion bar crossmember so when everything was apart we did just that. Once we got it back together, we realized that it didn't need to be done so I just purchased a used uncut crossmember and put it in (I just swapped that out today actually).

Here is a pic. The pic makes it look closer than it really is, I can easily fit my hand between that lower bolt in the picture and the crossmember. The transfer case is a NP241.



The drain plug is close but still accessible, it would probably make a huge mess since it would just drain directly onto the crossmember but with a large enough pan it would be ok.

I think the Auto-Trac rigs have a larger rear output housing on the transfer case, so they would probably be the rigs that need to have the torsion bar crossmember notched.
 
#30 ·
Doesn't sag a bit, I am not sure how much I cranked the torsion bolts up but it wasn't much at all. The 454 was probably about 800 lbs and the Cummins is about 1100 lbs. 300 lbs isn't that much of a difference. Plus I have seen a lot of this era truck with snow plows hanging out the front bumper and those weigha whole lot more than 300 lbs (not to mention the leverage weight from hanging off of the front) and their suspension seems to hold up fine.

The front doesn't feel any heavier than it did, it drives just like it used to, I am sure it would be different if I throw it into a corner but it's a Suburban, not a sports car.
 
#31 ·
I have to tell you you make this sound so easy.... most people say its a pain in the ass and you HAVE to do a body lift or a straight axle conversion to make it work. But by looking at the pictures it doesn't seem that bad at all. Yes it alot of work but doesn't seem like a ton of fab work. Maybe your just making it look easy. Either way great job. Any specs on the motor, did you do anything to it or is it just stock?
 
#32 ·
It was a lot of work but I had some really good help from a friend of mine plus the guidance from Auto World and this forum helped as well. Now that it is 99% complete, I will say it was much easier than I thought it was going to be, most of it was time consuming more than difficult. I am suprised how well the engine fits the engine bay especially considering this body style was never meant for an inline engine.

The motor is bone stock right now. The only upgrades it has is:

16cm Turbo Housing (stock was 21 cm)

1998 Dodge Intake Horn

Larger 1994 Dodge Intercooler and larger piping

Air Dog Fuel Pump / Filter / Water Separator

So really at this point, I have improved efficiency more than power. After a few months of driving it, I will start to build power, I just need to get comfortable with it, this is my first diesel.
 
#34 ·
That is my goal as well. The 454 Vortec that was in it towed fine, had a ton of power -- it had the Banks exhaust, headers, intake, etc on it, it was a very, very quick Suburban that pulled hard. The only issue I had with it was fuel mileage. The best I ever got was 15 on a freeway trip, my average (mostly in town) was 9-10 and when towing it was 6-8. We have a 31' Wildcat trailer which is probably 8-10k depending on how much we have loaded into it.

I am hoping to get ~20 mpg unloaded, I have seen people post better MPG results (25ish) but I am an optimistic person and don't believe anything until I see it. I am also hoping for ~14 towing.

With gas at $3.00 per gallon and diesel at $3.50, it would take about 35000 miles for this conversion to pay for itself. This is figuring 20mpg (old 10mpg) unloaded and 14mpg (old 7mpg) towing.
 
#35 ·
What do you tow? Camper,toybox? I have a 30ft car enclosed car trailer. Golf cart and racecar. Around 11-12k. My truck is small block powered and it sucks. 11 mpg around town 14 mph on the highway. I'd love to see 18-20 mpg unloaded and 10-12 mpg loaded. Like you, I'll believe it when I see it.
 
#38 ·
I used the same one for now and it seems to work fine. When (not if - still original transmission with 96k on it) the transmission goes, I will do something different. A torque converter company that I talked to said that they recommend a 1700 stall converter which seems awfully high to me. I was thinking running about 1000 stall. I will contact a few more manufacturers before I make that decision when the time comes.
 
#42 ·
Hey Crummins,
when you go looking for a converter give Art Carr a call. Ever heard of him? That's who my son ended up having build him one for the powerglide in his S10. His is down around 900-1000, not sure exactly. His of course is for a very particular application being the s10 is so light and he isn't going to pull anything. It'd be interesting to see what he would suggest for your burb.
 
#47 ·
i just wanted to thank you for the pics and i just got my first cummins its a 1993 3500 dually 2wd this weekend the wife took it for a drive and loves it now she wants me sell the mini van get a burb and put a cummins in it so thanks i will not have to drive that dumb mini van again
 
#49 ·
Parking Light Modification

Here is how I made the parking light fit:

This is the stock parking light:




I cut it down like this with an air powered cut off wheel:



This is how it fits:



Bulb in it -- I had contemplated leaving it like this with just one bulb:



But I decided to drill a 1" hole and put some notches in it with an air saw (couldn't find a file that worked well enough). It is a little ugly but it works:




Now it has 2 bulbs in it:


Finished one more project on it:



I am going to cap this with some sheet metal but I didn't have any scrap in the shop that would have worked but this works for now.
 
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