The Story Of A Cummins Suburban (Lots Of Pics)

[Long Roof]

At least you haven't stalled out on the project. Even at slow, things are still moving forward. This is a great build so far. Can't wait to see the sub belching black.

Can't believe the heat you guys in the southwest have had to deal with this summer. Its been the exact opposite here in the rust belt. We've consistently had low to mid 70's all summer long. I love it myself but you could never imagine all the local people *****ing that its too cold to use their pools.

Stay cool!

[jbclassix]

Are you using an original dodge version NV4500? Just wondering if you have taken care of the spanner nut on 5th gear issue? Of the 2 transmissions I have had, both have had the nut back off, one stripped the splines on the mainshaft and 5th gear. Green locktite and a staked nut has kept the second together since it came apart.

Love the build!

[mosesburb]

No, it is a GM 4500. I converted the front of it to the Dodge HD input shaft and bearing retainer. I had to have the pilot of the bearing retainer where it fits into the trans case machined down to fit into the bore of the GM trans. Both the GM and Dodge use the same input bearing, but the Dodge has a heavier "ring" around it.
As far as the 5th gear nut, I am using the GM setup that has the vibration damper on it. I discussed the matter with Dan at Quad 4x4 and he said that if the gear and the damper still have a heavy press fit, I should be ok. I am not towing anything heavy with it, so I put a bunch of red loctite on it and with a new nut, torqued the snot out of it--325ft/lbs is a ***** even with the case strapped to the bench.

[mosesburb]

I changed out the tires and wheels. The BFG mud tires had been sitting for many years and were starting to crack in the sidewalls. I had nine (yes nine) tires given to me awhile back, so I picked up some stock steel wheels from tkorinek, and had them blasted. I brought them home, painted them and had the tires mounted up on them. I also scored some stock 3/4T hub caps from him some time ago. I threw those on it and ended up with the "old man" look to the truck.

They are not too sporty, but I am really liking them. It reminds me of what these trucks looked like when they ran around back in the '70's.

Maybe it's just me??

[t korinek]

Man thats a lot of good work you've done, first time checking your build out. Those wheels look a lot better than when they left my yard!
Tom

[gerfunken]

I'll guess 7200 and 20 MPG.....

[pickup67man]

Love the idea of a diesel in an older Chev. Have a new Chev with a Duramax and an old Chev and like the idea of mixing the two.
I'd say you are 6500 lbs and 25 mpg.

[ldg72chevy]

What did you use for a speedometer? Doesn't the NV4500 have a electronic sender?

[mosesburb]

Originally Posted by gerfunken

I'll guess 7200 and 20 MPG.....

A fuzz high on weight, but close on mileage. My K30 DRW 6.2L with three full tanks of fuel was right at 7200lbs.

Originally Posted by pickup67man

Love the idea of a diesel in an older Chev. Have a new Chev with a Duramax and an old Chev and like the idea of mixing the two.
I'd say you are 6500 lbs and 25 mpg.

Now you are close on weight, but high on mileage. I guessed 6500lbs myself and we were both 80lbs off. It scaled right at 6420lbs and the first tank of fuel netted me 19.5 mpg. There was a 95mi round trip of highway driving on it. The next tank of in town and significant rush-hour traffic with a/c netted 16.6 mpg. My major problem is I have WAAAAAYYY too much gear. I did the math and *ideally* I should run 3.23 gears. Now I would not go that high, but I have a complete 3.54 D70 out of a Dodge with a Cummins, but I started investigating the cost of freshening it up and then re-gearing my D60 for the front and figured for that amount of money I can buy a bunch of fuel, so for now the 4.10s stay. A higher gear would make it more fun to drive though.....

Originally Posted by ldg72chevy

What did you use for a speedometer? Doesn't the NV4500 have a electronic sender?

For a 2wd trans, you would be correct. With the 4wd setup the speedometer is driven off of the output shaft of the transfer case so it has a cable just like stock. On slight side note, with my calculated guess of drive gear and driven gear I am only one mph off at 50 mph. I'll call it my awesome ability at estimation and calculation, but pure luck probably played as much of a role as my calculations did.

[jbclassix]

Unfortunatly if you want to keep the 14b the highest match gears you could use are 3.73s. I dont blame you on not wanting to use the Dana 70. I know it is a beef of an axle, but every one I have come across has been a PILE.

I had the same problem when I lifted my 6.5l 96. I wanted 4.56 gears and 35's for wheeling, but that made me tach out at 75 MPH and 16 mpg with propane. She could pull ANYTHING though! Have you consideded a Gear Vendors Overdrive? You could split gears for even better fuel mileage!

[LOW DOUGH]

I realy like what you have done to your burb! Can't wait to see more pics!

[JeremyPenner]

nice project! mo pics!

[Jtrux]

Very nice, love the wheel/tire combo, same ones I purchased for my blazer.

[mosesburb]

Well, I can't find the pics I want to post, but I have been driving the hell out of this thing so I figured an update is due. With the price of diesel fuel and the mileage this gets, it is the most economical vehicle I own (never saw that coming).

Had a minor major issue awhile back when the anti-rotation strap on my fan clutch, which was designed to always be in tension, went into compression for some unknown reason. When this happened it bowed the strap enough for the fan blade to hit it and shove it into the radiator wrecking the fan and putting a pinhole in the edge of about six tubes of the radiator. Not bad. I drove it home, tore it down and took the radiator to get fixed. Well the repair did not go so well and the core got ruined, so I ended up buying a new radiator. The fan blade got dinked up a bit, so I got a new one of those also. I went with a small block fan this time as the big block fan took so much power to turn and even above 110* the fan clutch never came on for temperature--it only came on for the a/c pressure or by the manual switch. It was horrendously loud also. The one thing I did not check was how overdriven the fan pulley is on the Cummins versus the big block. At about 2k on the Cummins it sounds like about 5k with the big block. I will not know how well it works until next summer, but for now it is fine as it never turns on with the current temps. I replaced the anti-rotation strap with a piece of 1x1/8" flat stock with steel locknuts on the ends so it can move without destroying what it is bolted to. The thing I wonder about this carnage is why it waited 1100 miles to happen. Oh well.

Then last week, I get off the freeway towards work and notice I can't see out the back window very well. Hmmm, it was not that dirty when I left the house. Hmmm. What could do that?? Hmmm. I get to work and look underneath the truck and the whole underside is dripping what appears to be enigne oil. Oh my, this can not be good. It wasn't. Come to find out, the input shaft seal on the injection pump decided to take the day off without telling me, allowing fuel to flow freely into the crankcase. I had it hauled home and picked up the seal the next day. I actually picked up a pump reseal kit. It has a bunch more parts than a q-jet kit and only cost $19.50. Got home that night and pulled the injection pump out to change the seal. While it was out, I removed a child-proof cap off of one of the adjustment screws on the pump and gave it a couple turns in. When I drained the oil I figured I should use a five gallon bucket just in case it has way more than the 11qts of oil. Well, it did. I drained SIX GALLONS of liquid that looked like oil, but flowed and smelled just like diesel fuel out of it. I checked with a friend of mine at a heavy truck dealer and got his recommendation on an oil change interval and what to look for. He said watch the blowby and the oil pressure. My oil pressure had dropped significantly, but I did not know if that was due to bearing issues or just no viscosity.

After the oil change, my oil pressure is right where it used to be and there is no blowby to speak of, so I would say the bullet got dodged. When I reinstalled the injection pump, I advanced it a bit and that, coupled with the turning of the screw that no longer has the child-proof cap on it resulted in a whole ton more power--holy cow. This thing moved before, but it flat hauls now. Running down the freeway seems like it requires less effort and the whole sound of the motor has changed. All that from an advance and turning a screw a couple turns--wow.

So all seems well now. Runs good, drives good. I am getting the D60F put together, so that should be going in soon hopefully.

[LOW DOUGH]

Originally Posted by mosesburb

it is the most economical vehicle I own .........This thing moved before, but it flat hauls now.

That is just awesome!

Glad everything turned out well.

[lyrikz]

Forgot about this thread.
Im in.

[Big J'72 GMC]

wow, this is now my bible, have read the whole thing about 3-4 times now, hope it goes half as well for me as it did for you, prolly wont, luck isnt my best feature

[scottydawg]

That is a badass truck, but the color combination on the firewall and outside confuses and scares me a little.

[mosesburb]

Originally Posted by Big J'72 GMC

wow, this is now my bible, have read the whole thing about 3-4 times now, hope it goes half as well for me as it did for you, prolly wont, luck isnt my best feature

Hey, at least you have a photographic guide to lead you into despair--I had to find my own way.

Originally Posted by LOW DOUGH

That is just awesome!

Glad everything turned out well.

Thanks, me too. Funny thing was, I still got 14.7mpg with who knows how much fuel flowing into/through the crankcase.

Originally Posted by lyrikz

Forgot about this thread.

Me too, kinda.

Originally Posted by scottydawg

That is a badass truck, but the color combination on the firewall and outside confuses and scares me a little.

Thanks. Don't be frightened though, it's just paint. Yeah, that is something now that I wish I had not done then. I painted the dash and firewall in preparation to change the color from orange to green. I did this when I had disposable time. Now, with a non-scheduled job, family time etc, a color change is no longer likely, but I still have the green firewall and dash. The strange thing is--I actually like the orange color now--damn.

[truckfan]

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

[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.

[Critter]

Originally Posted by truckfan

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

NO KIDDING! That suburban is a BEAST!

[FRENCHBLUE72]

This should be put in to the f a q section this is a great write up..

[Critter]

Originally Posted by FRENCHBLUE72

This should be put in to the f a q section this is a great write up..

[LOW DOUGH]

That wiper setup is awesome. I will have to remember this so I can do it. were did you put your reservoir? Do you have a pic of it? I also want to see the tall skiny mud tires on it.