The Story Of A Cummins Suburban (Lots Of Pics)

[mosesburb]

Gather 'round boys and girls, it's story time.
Once upon a time, I acquired a '72 K10 Suburban that no longer posessed an engine or transmission. It did have rear a/c though.



It was fairly straight and quite complete. I started tearing into it and modding and replacing a bunch of stuff (my wallet thought I replaced everything).

I modified the evaporator housing to accept a later model evap core that uses an accumulator and orifice tube instead of the mechanical POA valve and expansion valve.



I cleaned up the dash replacing most of the a/c ductwork, the a/c controls, the vacuum pods, rebuilt the steering column, and insulated the floor and firewall. I never liked the manual transmission brake pedal, so I modified it. I also added the wider gas pedal from a '73 up truck.



The electrical system in these trucks was inadequate in stock form (and a fire hazard) so I made my own wiring harness using a fuseblock from a mid 80's Suburban and HD Bosch relays for the high amp draw circuits.



A 20 gallon fuel tank seemed laughable, so I added a 31 gal from K5Nutt/azblazer's '79 K5 when he switched to TBI. I also threw a set of 3/4T axles at it.



Then, I added a Gen V 454. I disliked how GM mounted the a/c condenser in front of the core support making it 5" too short, so I put it behind the core support. Actually, I put a '82-'83 Suburban condenser behind the core support. I got one of the last ones available for a rear a/c application (rear a/c units got 13 fins per inch instead of the normal truck/K5 units 10 FPI).

I wanted to use the tall radiator from a '73 up in it, but I had someone tell me that it won't fit and can't be put in. So I put one in. I got the Delco service replacement which is an aluminum core instead of the original copper/brass. I also installed a BRAND NEW BOOSTER. Having seen several friends go through reman after reman, I wanted to subtend that arc so I found a unit that was fairly easy to adapt and installed it with a new master and prop valve.





I was also told that I had to use the short water pump on the big block because a long water pump would not fit. So, once again, heeding their advice, I installed the long water pump and used a factory BBC fan shroud from a '73 up truck with a few minor mods. I ended up with the fan half in and half out of the shroud just like it should be. I'm glad I heeded that warning.....



I added a 4" lift and ended up with something that looked like this:

[mosesburb]

I built my own exhaust system for it; a dual 2.5" into a single 3.5". It sounded great.
I drove the truck around the block a couple times and then, then, I bought one of these:



Yes, it is a Cummins 6BTA. It is a first gen unit and I got a complete Banks kit with it. I basically bought a Banks kit and got a 6B thrown in for free. So I tore the 454/TH475 out of it and sold them, had a little boy and it has sat in the driveway for the past five years.

But recently things have changed.
A test fit:



and installed:





Notice a partial hydroboost unit on firewall.



I set the motor as far back and as far down as I could. The far back is good--I have lots of room for the fan and clutch. the far down is preparing itself to kick me in the junk on the first trail outing: (it's hard to see in the pic, but there is about 4" of clearance between the D44 housing and the crossmember--I'm really going to aggravate this clearance with the D60 I have for it) The sides of the crossmember are 45deg, but the bottom of the crossmember is actually not level. It is canted up on the diff side to create a bit more clearance. I don't like it, but I don't want to raise the motor and I don't want more suspension lift.



I devised a simple crossmember to support the back of the motor utilizing the lower two transmission mounting holes to support the engine in the correct location without a transmission, so I can set up the underhood "things" without having to build the trans right now.

Well, I am tired of typing and loading pics, so the story will end here for today. Stop back to read of further adventures in the future.

(I posted this on another site, but I figured since several of you have been kind enough to sell me parts for it, I should share here)

[big blue 72]

THAT is one sweet Burb you got there, Mr.Moses!
Wecome to the Site!

[IAFF2407]

man that is alot of work done. do you have to beef up the front suspension for the motor?

[72 sub]

Very cool welcome to the board from Canada!

[mosesburb]

Originally Posted by IAFF2407

man that is alot of work done. do you have to beef up the front suspension for the motor?

Believe it or not, the front springs did not drop any measurable amount. I would have thought 1100lbs would have dropped the front end a bit, but it didn't. I am not going to do anything with the springs until I drive it and let everything find its happy spot. I do have a Dana 60 front axle for it, but right now I am trying to get it drivable to hopefully increae my gumption to keep at it.

[mosesburb]

With the crankshaft centered between the frame rails, the turbo was all over the evaporator housing--not good. I had two options; one was to scrap all of my work on my existing evap housing and go with a Vintage Air type setup -or- find a different manifold. I was leaning toward the second option because the manifolds are actually priced quite reasonably. At some point I got a strange idea to try inverting the manifold to see if anything changed. Boy howdy, it sure did. Everything ended up fitting great. The best part of the whole thing--IT WAS FREE!!!



Then it was on to the intercooler. I made this cardboard silhouette to get it exactly where I wanted it. It looks extremely simple, but that thing too about an hour and fifteen minutes to make.



Now, for all that work, all that I really needed was the ends to located a couple holes because the Banks intercooler for the first gen Dodges is not flat on the engine side. I *believe* the engine side of the outer "tanks" are tapered for condenser clearance, but since I rear mounted my condenser, I wanted to "flush mount" the back of the intercooler to the core support. This required precisely locating where the "tanks" taper and that is what the vertical lines indicate.





Now that I knew where they needed to be, all I had to do was trace them out onto the surface that is not flat.





Then, all I had to do was cut them out.





Then throw an intercooler at it. This pic shows the high mount turbo configuration. It looks kind of strange from this angle, but with all the accessorial crap going on the motor (and from a different angle) it looks pretty cool up there.



This pic illustrates the way the mounting tabs are configured. I *could* cut them off and re-weld them in a better place, but since the nearest TIG welder I have access to is about 40 miles away I decided to do something different. I took the rubber isolators off of the engine side and mounted them on the front and made two small plates to cover the hole that was cut for the tabs to go through and bolted the rubber isolators to the back side of the plates. It worked slick and actually looks ok (once the grille is in, they will pretty much be hidden by the intercooler itself). Also, this pic shows the full height condenser pretty good.



That's all for today.

[53burb]

Hey Mosesburb,
Looks like GREAT work!! Where in Phoenix are you?? I live in Queen Creek. Anyways, I have a 69 2wd Burb that I am going to be putting a 454 with a serpentine belt setup into it. I wanted to avoid using an electric fan setup if I could. Could you tell me more about the radiator & shroud setup you used? I know my fan would have to be a reverse rotation fan, but I'm not sure if the clutch has to be strictly forward or reverse or if it doesn't matter.

Chris

[mosesburb]

Hey Chris,
You will need a reverse rotation fan AND fan clutch. The radiator I used is a '73+ Chevy truck unit and the fan shroud is also a 73+ unit for a big block. It is not a bolt in and trying to explain what I did would take quite a bit. I think if I was to try it again, I would check out an 88+ setup as they are shorter in height which would make the top easier to adapt. For the top, I had to bend up a piece of sheetmetal and TIG weld some provisions for the radiator bushings to fit into whereas with the 88+ this *might* not be necessary. You would still have to fab up a lower mounting setup to hold the new "funky size" radiator. Basically with my condenser setup, I had to make a plate/mount to hold the bottom of the radiator that moved the bottom of the radiator toward the engine about 2". I made a support structure then put a piece of sheetmetal on it and then fabbed up some rectangle pieces for the radiator bushings to fit into and TIG welded them onto the sheetemtal then attached that to the support structure. Not real easy to do, but I had just recently purchased the radiator and shroud so I really didn't want to buy more and when I was told it couldn't be done, well, that was all I needed to make it work.
Hope it helps.
If I take the radiator out again, I'll try to take some pics of the setup.

[53burb]

So are you going to use the same radiator/shroud setup with the new engine?? Before I commit to using the electric fan setup, I plan on looking at the fan/clutch setups from the 88-98 trucks or cars or anything else to see if there is one short enough to use with my radiator...

[mosesburb]

Yeah, I'm using the same setup. The fan clutch you will need is 3-5/8" from mounting hub to the front. The only way to get a shorter unit is to go with a lighter duty one. I highly do not recommend doing this. That motor needs all the help it can get for summer time. Hopefully you will have room for it, but the 2wd trucks had their motors located further forward than the 4wd trucks did. I had to "massage" my firewall (witnesses probably would have called it bludgeoning) to get some clearance at the back of the motor whereas you probably have a fair bit of room back there stock.

[53burb]

Thanks for the info....I will definately try to get a short clutch once I get to this point. I figured I wasn't going to be able to find one to meet my needs, thats why I seen yours & thought that maybe it was possible, but we'll see. Thanks for the info, again. Here is a link that addresses this subject.
http://67-72chevytrucks.com/vboard/s...d.php?t=292393


Chris

[mosesburb]

Saturday night I got some serious work done on the power steering lines. Finding hydroboost fluid lines for a '72 Suburban with a Cummins is a bit tougher than it sounds. I found some that are pretty close and I have them roughed in pretty well. I was planning on getting them finished today after the sun put the truck in the shade, but sometime after I closed up shop on Saturday and before I got up Sunday, some schlup decided my mailbox would look better on the ground instead of remaining atop its stick in the ground. So, today, instead of making forward progress on my big orange yard ornament, I got to do mailbox repair. Next time they try it they had better bring hand tools or a saw.



By the time I got done with this and cleaned up, it was time to call it a day.

[Long Roof]

Pesky Rascals! Anything to kill a few productive hours.

[MrBeast]

Nice to see I am not the only one doing a Cummins build here. I will be paying attention to how yours goes, very cool burb.

[mosesburb]

So, once I got the motor in the frame, I was greeted with a problem that would require significant amounts of cash to solve. The fan hub my motor came with drops the fan down and kicks it over to the driver's side. This created two issues: One was the fan was too low. With the motor set as low as it is, the fan was literally a couple thousandths from hitting the crossmember below it. The second was with the hub kicked over to the driver's side, it made using some type of production GM fan shroud impossible. I managed to solve both of these issues by taking a dumptruck full of money down to my Cummins supplier and trading the money (and the dumptruck) for two parts.

Original Fan Hub



Mounted on engine. (I used some caustic cleaner on the motor that destroyed the Cummins paint pretty good)



Original hub on left, new, platinum plated, diamond encrusted hub on right



Of course, with that new hub, I'll need a gold plated pulley to accessorize it:



Now, with all that being done, I acheived a few things. I am able to clear the crossmember with the fan--good. It brought the fan back to the center of the motor, so the use of a production shroud of some sort is a possibility. The last thing I acheived was I gained more distance from the hub to the radiator as this pic (poorly) illustrates



That additional clearance gives me more than enough room to run one of these!!



Yes, as a matter of fact it is a brand new (NOS) Horton electromagnetic fan drive (clutch). These thing have been discontinued for many, many years. I have been looking for one for many years and never came across one. That all changed recently, so now I have the fan clutch I wanted for this motor and the room to run it!!

More to come. Stay tuned.

[Hart_Rod]

Your Burb's going to be pretty sweet when you get it done.

[mosesburb]

Long ago, I took the Cummins water inlet housing and cut about one inch off of the hose nipple, then took a small block water pump and cut the inlet off of it. I gave that to a co-worker to turn down the iron above the hose nipple to the i.d. of the Cummins inlet then brazed them together. I ran into some interference with the frame though. The top of the frame rail flares up in the area of my water inlet rendering it useless--swell. I have made other plans since (another trip to the Cummins supplier with a dumptruck.....) so this setup is not going to be used, but the "flare" still creates an issue with the new plans. (The first few pics of the Cummins installed show this flared lip better than this pic)



So I removed the "flare"



Made a template



My personal machinist Russ, alias BadDog, hooked me up with a chunk of frame to make a filler piece out of so it would be of similar metallurgy.



I then cut it out



Then welded it in and painted it. It is hard to see in the pic, but the top of the frame rail is flat from left to right (inside to outside).



Then I got to work on the fan shroud. After I mounted the fan on the platinum plated, diamond encrusted fan hub I started taking some measurements. I was coming up with dimensions within 1/8" of the dimensions of the 73+ big block shroud I modified for the 454. Hmmm, this could work. I dropped it in for a test fit and it hit the crank pulley something fierce. So I took a couple measurements and determined removing one inch off the engine side of the shroud should make it fit. Hmmm, how to cut one inch off accurately so that it doesn't look like you mixed a twelve pack and a chainsaw to get your results. I thought about a few possible options and came up with one that worked pretty good. I put a miter gauge in my jigsaw and set it at one inch. Then I cut into it and spun the jigsaw around the inside diameter of the shroud cutting exactly one inch off of the shroud. I dropped it in for a trial fit and it passed. Fan blades are half in and half out just like they should be. I still have the stock viscous fan clutch on it in the pic.




I know very little about working with plastics, so I did not know what to try to clean up the burrs from cutting and generally smooth out the surface. I threw a piece of 80 grit on the D.A. and got at it. Man, that worked friggin' sweet. Easiy cleaned it right up and was able the chamfer the edge to make it look nice.



Lastly, I got my power steering cooler mounted. I wanted to mount it to the back of the intercooler, but the mounting was going to interfere with "future plans". I decided to mount it directly to the condenser. I did not want to, but my options were limited. It actually mounted up well and does not move at all, so there it stays. I also mounted the power steering filter, but I forgot to take a picture of it.

[Long Roof]

Lovin' it !

[Jtrux]

Wow, this is gonna be something fierce. So how long before this bad boy runs, oh and what tranny/xfercase you running behind it (please say NV4500)

[mosesburb]

Originally Posted by Jtrux

Wow, this is gonna be something fierce. So how long before this bad boy runs, oh and what tranny/xfercase you running behind it (please say NV4500)

My wife asks me the same question. I don't have a time frame yet, but with every piece I add, I'm one piece closer.

Ok, I'll tell you it's a NV4500. It actually is. I think automatics behind diesels are blasphemous. I know they are quicker and blah, blah, blah, but I don't care. The 730 inch diesel I drive daily has a manual and all the diesel engines I drove growing up had manuals so I guess I'm stuck with manual.

A NP205 will be located behind the NV4500. There is a story behind the NP205 that I am using, but I will save the drama for when it makes its appearance.

I'm trying to mentally prepare myself to start the wiring process. I actually went out in the shop and dug out the harness that I built for the big block. I admired the work involved and quality of construction. Then I remembered the work involved, the time it took to make and quickly put it back down and came back into the much cooler house. Maybe tomorrow.......

[Jtrux]

Don't laugh but the Sterling I drive at work is an auto but in my defense I really wish it was a stick.

[mosesburb]

Thanks guys. I've been fabbing my way into more problems. I decided it is about time to start thinking about starting to think about wiring this mess. I dug out the harness I constructed for the big block and stripped the looming off of it to see what I was going to be able to reuse (little) and what I was going to have to remake (lots!!). Anyways, I figured before I start doing anything electrical, I had best get some batteries in it. Well, at least figure out exactly where they are going to go. In its original configuration, the battery was on the passenger side mounted parallel with the core support. That works fantastic when you do not have an intercooler. I happen to have an intercooler. That being the case, I needed to come up with a plan B. I figured out that there would be enough room on both sides if I mounted the batteries perpendicular to the core support. Then all I had to do was come up with some type of mounting apparatus. No big deal, eh??

This is what I came up with:



This is what the driver's side roughed in looks like: (the pic is kind of deceiving because the battery is actually level)



This is the mounting configuration for the driver's side to the rear of the core support. The tube that goes above the headlight is mounted to the top bolt that holds the core support ti the inside/back of the fender. The vertical tube that has the two bolt holes in the top goes down and has two bolts lolding it to the bottom flat part of the core support. (You can see the power steering filter mount below the tray with the vertical tray support running between the mounting tab and the fluid ports)



The rear of the tray is basically free-floating except for a mounting tab (more like a block) on the bottom of the tray that mounts to the inner fender well.



The passenger side is *basically* a mirror image of the driver side, but not really.



They actually turned out pretty good. When I was figuring out the first one, I was not too thrilled, but I realized that this was about the only way it was going to work and it worked out good in the end. With bolts in all the holes, I dropped (literally) an Optima in each one and they did not budge at all. I then grabbed the batteries and tried shoving them around, front/back and side/side and they do not move at all. The strangest thing about this is these things are actually pretty light--not that weight is an issue (obviously), but usually I tend to overbuild things to the point I need a gantry crane to install whatever it is I just engineered.

Man, for such a cavernous engine compartment, I sure seem to be running out of room quickly.

[mosesburb]

Thanks Jack
I moved on to the hood latch and latch/grille support. Neither of these items were designed to be used in conjunction with an intercooler. I still have an intercooler.

Initial fitment of latch:



Better shot of clearance from latch to intercooler:



So the latch fits good. The support for the latch mechanism and grille needs
some work to clear the intercooler, so another template is in order. The template is actually sitting on top of the latch/grille support:



A little work with the cutoff wheel and there is clearance. I had to cut the bottom of the support off because the bottom of the intercooler is in the way of the factory mounting. I made a support for the bottom out of some .187 flat stock and tacked it to the bottom of the support. Welding to the vintage iron is great--so easy compared to late model tin-foil.

Here it is roughed in: (The pic doesn't show it well, but there is about 1/2" of clearance between the support and the intercooler)



I still have some more work to do on the support. Some family came over for dinner and they felt I should stop what I was doing to eat. Some people...

The fe-mailman brought me something today:



Hmmmm.

[Palf70Step]

You are doing some great work. Love reading/seeing how your doing it.