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.

[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.

[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.

[Hart_Rod]

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

[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.

[Palf70Step]

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

[Critter]

HOLY CRAP THIS IS A SWEET BUILD!!!

[rockwall-burb]

Very cool story and truck. I've actually been watching Trucks on Powerblock TV lately as they are putting a similar Cummins in a late 70s Ford Crew Cab. Different truck but same problems with the manifold and turbo fitment etc..

Anyhow I've been looking for a 3/4 or 1 Ton Longbed 4x4 to do the same with so great to learn from your notes. If you haven't made your mind up yet on wheels I saw a 72 longbed 3/4 ton 4x4 truck the other day with a set of factory OEM Hummer Wheels on it that looked pretty tough. I attached a picture of the style. the basically ran these with the factory 8 lug center caps from a late 80s style truck and it looked pretty nice. Like it was made to be that way.

[mosesburb]

Originally Posted by truckfan

subscribed. makes me feel worthless w/ mine little pansy projects

Hey, this project is nothing more than a whole bunch of little projects taken on simultaneously. You can probably drive yours between the projects whereas I had to wait to get them all done. To be honest, I am really enjoying the small projects now--something here or something there or "I think I will just drive it today instead of working on it".

Originally Posted by ABHaulR

Now that you fixed the pump and turned it up. What is you mpg? I'm looking at doing the same swap in mine. For the gears, i was thinking of keeping my 4:10, just for the fact i run 18x39.5x16.5's. That might off set the rpm's.

As far as the mileage goes, I am in the middle of a testing phase right now. I got the "Drive it like you stole it" mileage and I am working on the more realistic mileage now. I plan to fuel it after work on Wed, so check back in a few days and I should have your info.

As far as the gears go, yes the tires will offset the gears nicely. The tires I have are only 32" tall, so I am at a disadvantage there.

Originally Posted by Critter

NO KIDDING! That suburban is a BEAST!

Thanks!!

Originally Posted by rockwall-burb

Very cool story and truck.

Thank you!!

Originally Posted by rockwall-burb

I've actually been watching Trucks on Powerblock TV lately as they are putting a similar Cummins in a late 70s Ford Crew Cab. Different truck but same problems with the manifold and turbo fitment etc.

They should have read this thread first....

Originally Posted by rockwall-burb

Anyhow I've been looking for a 3/4 or 1 Ton Longbed 4x4 to do the same with so great to learn from your notes.

Use at your own risk*.

Originally Posted by rockwall-burb

If you haven't made your mind up yet on wheels I saw a 72 longbed 3/4 ton 4x4 truck the other day with a set of factory OEM Hummer Wheels on it that looked pretty tough. I attached a picture of the style. the basically ran these with the factory 8 lug center caps from a late 80s style truck and it looked pretty nice. Like it was made to be that way.

Yeah, a buddy of mine had those on his Sub and they look real nice. I like them, and probably would have gone that way if I did not have so many of these tires hanging around. But being that I went this way, I have really grown to like the stockers I have on there now. Nothing flashy, but cool just the same--kind of unique anymore as everyone has put something "cooler" on their trucks. I am actually picking up a set of tall skinny mud tires to go on another set of these wheels, so I can have the off-road tires and keep my old-man hubcaps.

[mosesburb]

I have had a couple request for information about my windshield wiper wet arms. I was never a fan of the piston pump and metal nozzles that must be aimed, but require a different adjustment for no/low/high speed travel. I have adjusted the nozzles before and had decent success, but I really like wet arms (washer nozzles on the wiper arm).

I started looking around for vehicles that have the wet arms from the factory and came to the realization that GM trucks from '85-'91 came equipped with them. Being these are easy to find in wrecking yards, I chose to use most of this setup. Here are the major components (less reservoir, pump and hose):



The "Y" fitting in the middle takes the 7/32" id hose from the pump and splits it to two 5/32" id hoses that go to the metal tubes that have the brackets on them. These tubes serve two purposes: one is they reduce the hose from 5/32" id hose to 3/32" id hose (this is specific hose made for wet arms), the other purpose is to have a fixed point for the arm-hose to attach. The two long black plastic things are hose supports that attach the hose to the underside of the arm. The two little things on the ends are the actual nozzles. They do not look like anything special, but these things flow some serious liquid.

One of the problems of converting to wet arms is the original arms do not lend themselves well to nozzle attachment or aim. The factory we arms have a different blade attachment style than the original blades:



The original arms have the blades attaching inline with the arm. The factory wet arm has the blade offset just above the arm with the nozzle right below it. The nozzle sprays liquid parallel with the blade. This is where the biggest problem arises in the conversion. If the nozzle was to be put on the original arm, it would have to be placed further down the arm so it would be at an angle to the blade instead of parallel with it. I debated quite a bit on this and finally decided to make a hybrid of the two arms. I took the base of an original arm and removed the blade end from it. Then, I took a factory wet arm and removed the blade end to use with the base of the original arm. I had to shorten the blade end of the factory wet arm, drill a couple holes to match up with the base of the original arm and bend the end for the spring to attach to. I then used standard pop rivets and put the arms together:

(Original top, hybrid arm middle, OE wet arm asm bottom)



After the arms are made, the hose must be run up the underside of the arm. My local mom and pop parts house was able to acquire the wet arm hose for this purpose. Fishing it up through the spring was not too much fun, but I was able to get it through. After it exits the spring it goes into the black plastic channel that supports it until it gets to the nozzle (channel gets shortened about one inch).



The hole in the arm is a locating hole for the nozzle:



In all of my shopping I ended up using an '85-'91 reservoir. It had to fit in a very undesireable location (but the only location it would fit), and that reservoir fit perfectly. Normally, white plastic is cheap from GM, but this reservoir was not--in fact it was something like forty bones. That being the case, I purchased a used one. I like the reservoir because it has an integral pump that is hidden behind the reservoir itself. I bought a new pump kit for it: (Old parts pictured)



Normally, I only buy Delco parts for my rides, but this Anco kit has the same pump as a Delco kit as they probably were the original supplier for it to GM. The little white thing is a check valve so the lines will stay full of fluid and decrease the amount of time for the spray to occur.

Installation of the arms was the same as original, but there is a hose to deal with now. This is no big issue other than there is not quite enough room for the hose to squeeze through the hole with the wiper trunion and the cowl screen. I ground a small amount out of the id of the hole and made enough room for the hose to coexist with the trunion:



The only part from the C/K system that I did not use was the steel tubes with the tabs on them. I could not figure out a way to make either of them work on either side. Also to use them would have required a large amount of material to be removed from the cowl screen. I figured another system must use something different. I found that the Astro/Safari vans have wet arms also and use a simple plastic reducer/connector at the base of the arms. It can be removed without removing the arm or the cowl screen from the van. Work it out of hiding with a pair of needle nose pliers, then cut it off with a knife--do not try to pull it out of the hose or it will probably break.

I used all GM components from the same vehicle type (except for the aforementioned pieces from the Astro/Safari, but the diameters were the same as the C/K stuff) so that I would be dealing with a whole engineered system--not trying to reinvent it myself.

So, with all of this work, I sure hoped it would work. Holy cow, does it ever. I do NOT use it in heavy traffic because so much water comes out that I can not see through the water until the wiper blade clears it off. No piston pump washer/wiper setup I have ever used worked half as well as this setup does. It was a fantastic mod that I am very glad that I took the time to do.

[thirdstreettito]

Awesome!

[mosesburb]

Well, I got some miscellaneous "stuff" done recently. I got the fittings and nipples on the power steering filter figured out. It doesn't look like much, but it took some time to figure out the angles to set the fittings at to keep the hoses from kinking when coming into or going out of the filter head.



I also got my electric fans mounted. This was a bit tougher than I expected because of the clearance (or lack thereof) between the intercooler and the power steering cooler. With a little creativity and adjustment of mounting shims, it was able to be accomplished.



With the fans mounted, I was able to install the intercooler (hopefully for the last time). I have not started building the wiring harness yet, so the wires are just tucked out of the way for now.



I also finished hacking the hood latch support. I removed so much of it for intercooler and then fan clearance that I felt it needed to have some structure added back into it. I welded a piece of 1" x .125 flat stock to the drivers side of the support from top to bottom. It probably weighs as much now as when I started cutting it and is probably as stout, if not stouter.



I'm not sure why, but every time I make a battery tray I forget to provide a provision to hold the battery down. It is a minor detail, but one worth having available. Of course the trays were both painted and one was installed, but I managed to come up with a hold down provision that both functioned well and was relatively easy to install. I got a couple chunks of 5/16-18 all thread and a handful of coupler nuts. I welded one coupler nut on each side of the tray. Then I took a piece of all thread and dropped it through the top strap that I made out of some 1" flat stock welded to a couple pieces of 1/2 x1/2 angle stock. I threaded them into the coupler nuts that I welded to the tray. then, I threaded another coupler nut down the all thread until it hit the top strap and I cut the all thread off flush with the top of the coupler nuts. I then removed the all thread with the coupler nuts still on them and welded the top of the nuts to the top of the all thread. I cleaned them up and painted the nuts. I think it turned out pretty ok.



Along the way, my boy came out wearing a mask that my wife and he had made earlier in the day. He goes by and says he is going to go weld. Uh, ok. Have fun!! Well, I got to thinking about him welding and being that he can't watch me do it, I figured I'd make something for him to use. I started with a piece of 1/2" o.d. copper tubing for the handle/nozzle and soldered a piece of 12ga solid core wire in the center for the electrode. A little bit of black electrical tape and we had a MIG (GMAW) welder on our hands. After presenting it to him he said that he's been waiting for me to make one of these for him. Gee, sorry it took so long boy.

The end result:



Gorilla mask, er, uh, helmet down and welder in use:



Now, I am either too poor or too cheap (probably a combination of both) to pony up for the gold plated factory tow hooks. Seeing as how I have a set of '73-'80 hooks gathering dust, I figured they would go well with the rest of the originality I am maintaining.

Initial fitment:



Installed:



I think they look pretty good. Yeah, some factory ones would be cool and some extreme bends would probably be even cooler, but I think these are a good compromise between form, function and cost.

Maybe it's just me.

[Critter]

Look's incredible. By the way, with the cost of copper now-a-days, that toy welding gun probably cost more than the real thing!