The Story Of A Cummins Suburban (Lots Of Pics)

[mosesburb]

Last weekend the machine went on its first road trip. We went up north, about 135mi to a friends house in the middle of nowhere at about 7200' elevation. The Cummins ran great. I pulled the 7% grades at 75mph with throttle to spare. Had great weather going up. To get to his place you have to look for mile marker number something, then go half mile past, look for a locked Forest Service gate, unlock, re-lock, then you have a 1.5mi linear mud bog to get to a 10% grade, pull that and poof, you have arrived.

Going in:



It was real muddy. I learned last time that this mud is like super epoxy. Whatever it gets on, it stays on--clothes, shoes, trucks, anything. nasty stuff.

Near the end we picked up enough elevation and there was enough shade that the road was still frozen:



I did some work on his carburetor and had some fun for a few days, then it was time to leave. As we finished packing up, the snow flurries started. Just barely enough to be able to see. As we got to his property line a couple hundred yards away, the flakes got bigger:



By the time we got out to the gate, the flakes were getting larger:



By the time I got the gate unlocked, re-locked and unlocked my hubs, the flakes were pretty huge:



A few miles down the road we were seeing this:



A couple miles after that the road turned into this:



Shortly after that, the road turned into this:



I talked to my buddy today and right now they have four feet of snow on the ground and another storm coming in Tuesday night.

All in all it was a great long weekend. I learned that the Cummins does not appreciate being awakened below 32deg. I did get it started, but it did not want to. It was running on approximately two cylinders and dragging the other four along for the ride until I threw the grid heater switch and almost immediately it smoothed out and would run without my foot holding the throttle on the floor.

As far as the drive goes everything was great. My windshield washer setup (pushbutton auto detailer) was fantastic. I used it many times and except for when it was frozen solid, it was great. The truck drove great overall. The ONLY issue I have with it is a driveline-type vibration at 60-65 under power and 65+ under power but significantly less powerful. Also I learned that I can not coast down a hill over 65--under 65--fine, over 65--BAAAADDD!! I can either float or power down the hill but I can not coast or a horrible constant frequency harmonic vibration resonates throughout the entire truck (in or out of gear). I have tried different driveline angles, pinion angles, lowered the t/case, replaced some spring bushings, re-torqued every fastener I can find and nothing changes. I am going to have the driveline balance re-checked. I highly doubt that to be the issue as I have never had the slightest problem with any driveline that I have had done by the guy who did this one for twenty or so years. I hope someting is wrong with it just so I can be done with this, but I am not holding my breath.

Other than that it was a very enjoyable drive and fun to see this thing out in the woods finally.

[LOW DOUGH]

That's neat that your friends property is way out there in the midle of no where. Also neat to see the burb get out on a road trip and go out in the woods. That's some fun times!

I love your burb and want to see more pics of it. Got any of it out in the woods?

[MrBeast]

You know what would be perfect would be a PTO or a clutch diriving a hydraulic setup so you could have a 10 or 12,000 lb hydraulic winch on the truck.

Either way though, every time I look at the damn thing it makes me smile.

[Sub71]

Check your pinion bearing and your transfer case output bearings to see if that is your vibration. The noise that happens when coasting could be slack in your ring and pinion.

Nice burb, good luck!

[mosesburb]

Originally Posted by LOW DOUGH

That's neat that your friends property is way out there in the midle of no where. Also neat to see the burb get out on a road trip and go out in the woods. That's some fun times!

I love your burb and want to see more pics of it. Got any of it out in the woods?

Thanks. I do not know if I got the WHOLE truck in any pics (lots of pics of the hood). I'll take a look.

Originally Posted by MrBeast

You know what would be perfect would be a PTO or a clutch diriving a hydraulic setup so you could have a 10 or 12,000 lb hydraulic winch on the truck.

Yeah, that would fit the image of this thing now wouldn't it??

Originally Posted by MrBeast

Either way though, every time I look at the damn thing it makes me smile.

Haha, yeah, me too. Thanks.

Originally Posted by Sub71

Check your pinion bearing and your transfer case output bearings to see if that is your vibration. The noise that happens when coasting could be slack in your ring and pinion.

Well, that is part of the difficulty as every bearing in the transmission, transfer case and rear axle are brand new. The backlash on the ring and pinion was well within spec before (and after) I did the bearings.

Originally Posted by Sub71

Nice burb, good luck!

Thank you!!

[mosesburb]

Originally Posted by LOW DOUGH

I love your burb and want to see more pics of it. Got any of it out in the woods?

It looks like this is the best I can do:

[LOW DOUGH]

Good Pic! Thanks... got to get my fix on this thing.

[mosesburb]

Originally Posted by LOW DOUGH

Good Pic! Thanks... got to get my fix on this thing.

Glad I could help. Read on, there are a few more....

[mosesburb]

Well, with some help from some friends, I FINALLY got my BFG Mud tires on. A big thanks goes out to Jason4x4 from CK5, who not only found the last wheels that I needed, but also mounted and balanced them for me on his lunch hour. I would not have thought that finding what has to be the most common eight lug steel wheel on the planet would be so difficult, but every time I had something set up, it went to hell in a handbasket. Either the wheels were wrong or the person flaked out or, or, or...Jeez.

Anyways, I took a nice drive down to his place of employment with my wheels and tires and he put them all together. I brought them home and had to put them on as I was too anxious to see how it looked and also to see if my vibration would go away (more the latter, but I did want to see what it looked like).

So, without further delay: (It was overcast today so the pics aren't as bright as the should be)




A front view:



Now with the ever timeless hub caps:



So, all in all I like the look of it. It changed the entire image of the truck. The unfortunate thing is it also changed how it drives. The truck definitely has to be DRIVEN now. Not quite NASCAR sawing at the wheel, but it definitely requires attention going down the road.

So, now for the question you all are wondering about: Did the vibration go away??














Wait for it....





















Nope. Nothing changed. The vibration is still alive and well. I guess that rules out the tires/wheels/balancing from the equation.

Damn. Thanks again Jason!!

[RED72blazer]

it's late and I'm in trouble. But it was worth reading the whole thing. I love your writing style. Great build!

[jbclassix]

Does your vibration rattle your teeth out? I have seen this before! Believe it or not, a bent cage on a wheel bearing was the cause!

[71swb4x4]

Fantastic build!! You have some great talent.
What has your mileage been lately?

[83GMCK2500]

Awesome build! Way to build a great looking & performing Suburban. EXCELLENT!!!

So, details on those steel wheels and BfGs?

[mosesburb]

Originally Posted by RED72blazer

it's late and I'm in trouble. But it was worth reading the whole thing. I love your writing style. Great build!

Thank you!! I'm glad you enjoyed it--especially after you invested that much time into it .

Originally Posted by jbclassix

Does your vibration rattle your teeth out? I have seen this before! Believe it or not, a bent cage on a wheel bearing was the cause!

No rattle in my teeth. It is a DEEP harmonic vibration. It feels like every piece of metal is trying to explode simultaneously. It is like the harmonic vibration meets up with the natural frequency of the metal and at that point the vibration goes nuts.

Originally Posted by 71swb4x4

Fantastic build!! You have some great talent.
What has your mileage been lately?

Thank you!! Mileage in town averages right at 18mpg. I have gotten a best of 19.5 and ironically, that was in summer with the A/C on. The worst I have gotten in town is 15.5, but that was driving it like I stole it. The 18mpg is VERY repeatable. On the road trip last month I averaged 14.5mpg. The reason it is so bad is because the gears are so deep and the motor spins much faster than it should. If I can get the engine speed down at 65-75mph, then the mileage should go up significantly.

Originally Posted by 83GMCK2500

Awesome build! Way to build a great looking & performing Suburban. EXCELLENT!!!

Thank you!! Yeah, when you want a Cummins and don't care for Dodges, there is only one way to go I guess.

Originally Posted by 83GMCK2500

So, details on those steel wheels and BfGs?

The wheels are stock GM 16 x 6.5" steel wheels that were available on a bazillion GM trucks troughout the 70's and 80's. The tires are somewhat strange though. They are 255 85 R16 BFG M/T KM's. The size is what drew me to them as I was able to use them on a 6.5" wheel. The dimensions come out to be about 33 x 10. This was perfect--tall and skinny, ready to go on my "old man" wheels. They went on, but even with the hubcaps, the truck lost the "old man" image. That image is gone, but I think it still looks cool, just in a different way.

[83GMCK2500]

Originally Posted by mosesburb

Thank you!! Yeah, when you want a Cummins and don't care for Dodges, there is only one way to go I guess.



The wheels are stock GM 16 x 6.5" steel wheels that were available on a bazillion GM trucks troughout the 70's and 80's. The tires are somewhat strange though. They are 255 85 R16 BFG M/T KM's. The size is what drew me to them as I was able to use them on a 6.5" wheel. The dimensions come out to be about 33 x 10. This was perfect--tall and skinny, ready to go on my "old man" wheels. They went on, but even with the hubcaps, the truck lost the "old man" image. That image is gone, but I think it still looks cool, just in a different way.

HAHAHA! We think alike. 250,000+ mile motor in a 25,000- mile truck (Dodges). Yeah, I found that size tire a while ago, it is rather odd. Just about everything I've found in that size is a mud terrain, Toyo has a couple models (M-55 & Open Country MT) in it. I really like tall & skinny tires, I think they look good, perform better, and put less stress on the front end parts.

I am familiar with those wheels, I've got two sets + the original spare for my '83 (still has the original 215-85R16E tire on it too). Good choice on hubcaps too. I really like the Spicer hubs hanging off the D60, where did you find those?

[mosesburb]

Originally Posted by 83GMCK2500

HAHAHA! We think alike. 250,000+ mile motor in a 25,000- mile truck (Dodges).

Yeah, maybe not quite that bad but definitely not built to the caliber of the motor. It is very evident when you call around looking for a Cummins as most wrecking yards will have at least a couple compared to when you call around looking for a Powersmoke, you will call many that have none. Cummins outlast the Dodge they come in and Fords outlasts the powersmoke that comes in them.

Originally Posted by 83GMCK2500

Yeah, I found that size tire a while ago, it is rather odd. Just about everything I've found in that size is a mud terrain, Toyo has a couple models (M-55 & Open Country MT) in it. I really like tall & skinny tires, I think they look good, perform better, and put less stress on the front end parts.

I picked them because I could put them on my "old man" wheels--really. I have a set of aluminum wheels here that are wide--33x12.50s look right on them, but I have really grown to like the stock wheels and hubcaps.

Originally Posted by 83GMCK2500

I really like the Spicer hubs hanging off the D60, where did you find those?

Thanks. I bought them some time ago, but I do not remember where. Probably off of some internet site that has a classified section.

[Rush4x4]

A front view:



Now with the ever timeless hub caps:



That is quite possibly THE COOLEST SUBURBAN ON THE FACE OF THE PLANET! I wanted to do the same thing, and now I want to even more. Still, I don't have the skills you do, yet. Awesome work!

By the way, if you just wanted to walk around, taking pictures from all angles: inside, outside, upside, and down; so guys like me could short circuit their laptops with drool, that'd be okay with me.

Really awesome truck!

[Chevy-Art]

Wow, awesome build. I notice a lot of people using the Cummins diesel, why is that? Why not use the Duramax? I am diesel novice. Is the Cummins easier to get a hold of? More plentiful?

[mosesburb]

Originally Posted by Rush4x4

That is quite possibly THE COOLEST SUBURBAN ON THE FACE OF THE PLANET! I wanted to do the same thing, and now I want to even more. Still, I don't have the skills you do, yet. Awesome work!

By the way, if you just wanted to walk around, taking pictures from all angles: inside, outside, upside, and down; so guys like me could short circuit their laptops with drool, that'd be okay with me.

Really awesome truck!

Wow!! Thanks!! I don't think I can handle the responsibility of ruining laptops, but I'm sure more pics will be posted sometime.

Originally Posted by Chevy-Art

Wow, awesome build. I notice a lot of people using the Cummins diesel, why is that? Why not use the Duramax? I am diesel novice. Is the Cummins easier to get a hold of? More plentiful?

Well, I can't speak for others, but the reasons I chose the Cummins are:

Virtually bombproof--these motors have a 66,000lb GVW rating, durability of a mechanical diesel
Availablity--Most yards have a few
Simplicity--Depending on the setup, the only wires needed go to the starter
Coolness--Inline six sound, heavy underhood rattle

The Duramax is a sweet motor. It is almost hard to believe how well these motors run with little effort. They are a very complex motor that requires a good amount of knowledge in the electrical end of things to do a conversion with. I would imagine that they are quite pricey to purchase also. The Duramax will not run without electricity whereas once the Cummins is running no electricity is needed (provided the injection pump is not controlled by a solenoid).

Now, this comparison is Duramax (which all are electronic diesels) to a mechanical injection Cummins. Later model Cummins, 1998 and newer, are electronic, but I would not have done a conversion to one of those when the simplicity of a mechanical diesel is available.

[Chevy-Art]

What year are the preferred mechanical injection Cummins engines? Thanks for the info, Art...

[LOW DOUGH]

hmmm, is it a typo? You put a 16" tire on a 16.5" rim? The angles of the beads are different on a 16 and a 16.5 tire.

[LOW DOUGH]

Oh, The Burb looks great with it's new shoes.

[mosesburb]

Originally Posted by LOW DOUGH

hmmm, is it a typo? You put a 16" tire on a 16.5" rim? The angles of the beads are different on a 16 and a 16.5 tire.

I'm not sure where the 16.5 is coming from, but if I did state that then it is definitely a typo. The wheels are 16 x 6.5" wide and they have 16" tires on them.

Originally Posted by LOW DOUGH

Oh, The Burb looks great with it's new shoes.

Thanks!! I'm diggin the new look and the tires are finally getting broken in and calming down at speed so it is much easier to drive now (not as easy as the old man tires, but easier than it was when these were all squirmy).

[LOW DOUGH]

I just read it wrong. The Burb looks awesome. I like the pic with the caps off with the lugs and hubs hanging out.

[83GMCK2500]

Originally Posted by Chevy-Art

What year are the preferred mechanical injection Cummins engines? Thanks for the info, Art...

1st Gen: 1989-1993 Are a 12-valve engine mechanically injected via a Bosch VE rotary style injector pump.
2nd Gen: 1994-1998 Are a 12-valve engine mechanically injected via a Bosch P7100 inline injector pump. By far the 2nd gen's are the most sought after, they're the ones that have been used the longest to produce the big power pulling engines. Though you can convert the later 24-valve engines to the P7100 pump.