1990 GMC Suburban ... Cummins Powered
 

Hey Guys , I am getting started my 1990 Suburbeast ... its going to be ! Just got the full nose off . Pulled and sold the powertrain , just removed the fuel tank and some of the brake and steering .
I have just about all the parts , time is my only problem , I will pick at it an hour of two a day .
1990 V2500 4x4 ... 1988 thru 1990 had the thickest years for the frame ... 0.215 is the average on mine .
I brought the truck in from California ... rust free body .
Engine is a 1996 cummins 6bt with 100k from AZ ... no rust on this engine .
Transmission is a NV4500 HD dodge with all the upgrades .
Transfer is a NP205 has 29/32 spines .
Rears are new old stock military m1008 dana 60 / 14 bolt with lockers and 4.56 .

Truck is going to have around 8 to 9"s of lift , frame is going to be boxed and plated .
I just installed new energy suspension body bushings and a 1" aluminum body lift .

Here's a few picks to get the thread started .

greg

Re: 1990 GMC Suburban ... Cummins Powered
 

Welcome to the board, and very nice suburban! Are you planning on running 35's or bigger?

Re: 1990 GMC Suburban ... Cummins Powered
 

Sounds like that engine should be good for another 900,000 miles or so...

;)

Keep us posted on your progress.

K

Re: 1990 GMC Suburban ... Cummins Powered
 

I'm going to have to run a 38" tire with the 4.56 gear ... I was looking at a 385 Toyo thats a 38" radial ... nice tires .
Tonight I am going to work on removing the factory rivets ... They come out like butter ... I have done a cummins in the past and made the mistake of not removing the rivets first .
I had to go back and drill them out ... that was a ***** , alot of them loosened up and they would spin with out vice griping them ... I learned my lesson ... I was young .

Thanks guys

Re: 1990 GMC Suburban ... Cummins Powered
 

Are you talking about the "tamper proof" bolts bosch uses to keep you out of the AFC housing? Use a sharp chisel and a hammer and you can get them out easier than one would think. I do it all the time on dodge pick ups.

Re: 1990 GMC Suburban ... Cummins Powered
 

I have done a few of the AFC bolts before ... I was talking about all the rivets in the Chassis ... I'm going to remove all the rivets from the frame ... I allways thought they were a higher quality then they really are .
I did front body mounts because I am gong to plate the inside of the frame in that area ... I'm going 1/4 plate from the shock mounting area down past the trans cross member .
I will build my own new upper spring bushing mount to fix the 1/4 offset . That area is the weakest point on these trucks ... Plus I am boxing and plating the rest of the front frame section .
Just changed my mind on the springs I am going to use ... I was going to use a 8 inch skyjacker , I was talking to Jeff at Deaver springs , he's going to build me a pair of custom 52" fronts ... I 'll have to move the rear upper spring mount back 4.5" ... That should be no problem .

Re: 1990 GMC Suburban ... Cummins Powered
 

That should make for a stout frame. And yes, I agree those rivets or hucks suck to remove. An air hammer with a sharp chisel bit work really well or a cut off wheel and cut a cross in it and knock the chunks off. Either way they are a PITA! :lol:

Re: 1990 GMC Suburban ... Cummins Powered
 

Started to box and plate the frame ... Just tacked in the lower inter legs ... really made a huge difference in tightening up , theres going to be a lot more .
I'm not going to completely weld everything in til I have more supports in ... This truck was never hit or 4 wheeled , over the years the frame had either been assembled 1/4 out of rack or just from years of flexing .
when I drilled out all the frame un-sprung . I pulled every thing back to where it was suppose to be and added some temp rails to the front horn till I get everything boxed and tied in .
Got my new rear shackle mount drilled out ... its 4.500 back from the original location . The Deaver springs should be in a week or two ... they said 3weeks for the custom built 52's .

Re: 1990 GMC Suburban ... Cummins Powered
 

Nice project. I finished my 1991 suburban Cummins conversion in April of this year. I did a very similar conversion, but with an automatic trans. I also used the stock GM alt and AC compressor, in their factory locations. What style of crossmember are you going to use? Have you had frame flex or twist problems in the past with other conversions?

Re: 1990 GMC Suburban ... Cummins Powered
 

This is goin to be awesome. :metal:

Re: 1990 GMC Suburban ... Cummins Powered
 

Even with a K30 frame these trucks flex like crazy ... With the cummins weight and viberation the stock rivets seem to come loose in about 10k . This is my latest and greatest build ... Its last one also .
I owned a body shop that did custom 4x4's ... I have moved into another business , not as much of a passion but the money is there .
The springs that are coming for this build are custom Deaver springs . they will leave the axle in the stock location but are longer in the rear for a better ride . There also built to hold the weight of the cummins ... I think there going with 12 leafs in the front .
As for the crossmember I Had some much more stuff to fab I just called Scott from Tenn Conversions ... mostlly for the mounts but I got the crossmember ... I'm going to modify his mount a little bit , I need to clearance for the sterring crossover .
I completely removed the front crossmember ... thats getting mini "I" beam thats nice a low profile to clear the balancer .
I am also boxing the front horns and its getting a box steel crossmember in the forward area also .
I'll keep ya posted !

Re: 1990 GMC Suburban ... Cummins Powered
 

Have you thought about other crossmember options? I also removed my stock gas engine crossmember, and replaced it with a much beefer one that actually ties the two frame rails together. I did not have to use a body lift. Even the stock mechanical fan fits with the stock re-cored dodge radiator. I know others say it is not possible, but with carefull placement, it all fits. I choose to use a 4 row re-cored radiator because I tow in the summer when it is over 100 degrees and the AC on kill. Just some thoughts.

Re: 1990 GMC Suburban ... Cummins Powered
 

Awesome.

Re: 1990 GMC Suburban ... Cummins Powered
 

12 leaf springs in the front? Why? I have done 3 square body chevys, one with 3 leaf stock springs, one with 4" lift springs, and one with 6" lift springs. Non have had any problems with weight and the stock spring'd truck has a 8.5 boss v-blade. They all ride decent for what they are. The stock spring'd truck rides really nice. The only one I used a body lift on was an 84 K20 because I used a ZF5 5 speed. As far as the rivets ratteling out, I haven't seen that problem. The frame flexing, yeah, they do that with big blocks. :lol: Anyhow, keep up the good work.

Re: 1990 GMC Suburban ... Cummins Powered
 

I had a shop for over 20 yrs ... I had a guy working for me that just did rivet bolt replacement ... The trucks I built were 4x4s and heavy trucks .
I could not put a cummins in a truck with 3 leave springs ... Deaver is the best spring company around in my opinion .
I have built diesel trucks for guys with off the shelf springs and they do work . This truck is going to have 8 inches of lift and ride better than a stock suburban .
By the time I'm done with the frame boxing , cummins , winch , bumper ... I figure I am adding a extra 2200 lbs + over the original set up .
More leafs and flatter spring gives a better ride , Just the first 3 springs are part of the military wrap on these springs .

Re: 1990 GMC Suburban ... Cummins Powered
 

What kind of bushing is that? Is that direct from Deaver?

Re: 1990 GMC Suburban ... Cummins Powered
 

I think Deaver has 3 different bushing configurations , each spring is custom built , I need a 2.5 wide springs for my hangers and Dana 60 I was using .
Just got the steering sleaves welded in and fabed up the new inter rail that will be welded in later today .

Re: 1990 GMC Suburban ... Cummins Powered
 

Got the frame finished with the springs and Dana 60 under ... I'm actually putting on a pair of inter rails along the inside of the frame today .
Heres a pic with the springs mounted up !

Re: 1990 GMC Suburban ... Cummins Powered
 

Looks awesome. I sure hope once the Cummins is installed that shackle goes back a ways. Are the springs going to flatten enough with the weight to put the shackle back close to stock angle? I am in the planning and gathering parts stage for my CCSB 1 ton 4x4 build which will have a Cummins as well. Looking forward to following your build more. Keep it up !

Re: 1990 GMC Suburban ... Cummins Powered
 

I put about 2000 lbs on the front to see how far the front would settle ... Went down about 4" shackles came back . Once the build is on the road should settle a 1 below that ... should be in the 7" to 8" range .
I just got the inter frame rails prefitted and painted yesterday , going to get them mounted up and then I will get rear suspension on , I'm going with the DYI shackle flip and a set of superlift springs .
Then I can paint the whole underside of the body with POR 15 ... This body is like new and wanted to keep it rust free , the por 15 stuff is great .
Then I can drop in the motor ...

Re: 1990 GMC Suburban ... Cummins Powered
 

Nice keep up the great work makes me want to build one:metal:

Re: 1990 GMC Suburban ... Cummins Powered
 

Great build!

Re: 1990 GMC Suburban ... Cummins Powered
 

Thanks Guys , just got the inter frame rails bolted in . I was going to weld them in just because the amount of factory holes but decided to use hardware instead ...
I went with longer bolts on the driver side to use the extra thread as a mount for my new fuel and brake lines .
I was going to try and retain the original lines but after taking a look at it it would be easyer to run new ... The exhaust runs down pass side on the cummins plus the feeds for the cummins are on the drivers side .
Today I'm going clean under the truck and tear into the rear suspension and rear axle .
I have a DYI rear shackle flip , so I am going to drill out the rear hanger rivets , not sure if I am going to retain the stock rear springs ... There saging about 1/2 on the pass side ... I have a pair of 5.5 superlift springs that are new and may pull a leaf out to try and get them to sit a little flatter .
With the DYI flip that would put me around 10" of lift , the weight of the suburban should bring them down a inch .
I'll keep you posted .

Re: 1990 GMC Suburban ... Cummins Powered
 

Looking very nice!

Re: 1990 GMC Suburban ... Cummins Powered
 

NICE job on the Truck