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Detroit 6v92 Rebuild Questions

HTEoregon

Member
Joined
Jan 5, 2024
Messages
15
Location
Oregon
Good morning folks,

My current employer owns a 1988 GMC Brigadier with a detroit 6v92 under the hood. Motor has severe oil leaks coming from check valves on blow by tubes, and is blowing oil out of the exhaust stack. Owner of the company is attached to the tuck and would like to repair it. I'm hoping to get some insight from those of you who have experience with this engine. I have never worked on them but would like to preform the overhaul on it, it would be a great learning experience. The owner would like an estimate of cost to overhaul the motor.

How many labor hours would you estimate would it take to do a full overhaul on this engine not including removal/installation?

What kind of special tooling is required for these engines, estimated cost of tooling?

Things to look for when preforming overhaul, where could I source literature for this motor, and any other information you all think might be helpful would be greatly appreciated.

Thanks in advance and look forward to what you all have to say!
 

HTEoregon

Member
Joined
Jan 5, 2024
Messages
15
Location
Oregon
Thanks, I appreciate the input! I'm not opposed to buying tooling, and time isn't too much of a concern. Its just a water truck so it wouldn't need to be finished until this spring/summer.
 

Junkyard

Senior Member
Joined
Jun 5, 2016
Messages
3,636
Location
Claremore, OK
Occupation
Field Mechanic
X3 on swinging in a known good used or reman. They’re out there, still fairly common and not terribly expensive. Not a hard engine to work on but they do have their quirks that we’ve learned about over time many of which aren’t in the manuals.

I’ve probably got an extra set of tooling short of the ring compressor.
 

Coaldust

Senior Member
Joined
May 9, 2011
Messages
3,354
Location
North of the 60
Occupation
Cargo Tanks, ULSD, RUG, Methanol, LPG
It’s fun and noble to learn new skills, but if this is the first Detroit of your career, don’t waste the time and effort to mess with it. Especially, after all the re-do work inevitably required from the quirky nature of the beast. Have someone else fix it or purchase a swing engine.

Truck Shop could probably help. He loves those things. Drop it off at his place.
 

1693TA

Senior Member
Joined
Feb 27, 2010
Messages
2,687
Location
Farmington IL
Occupation
FAA Radar Engineer, (Retired)
The 6V-92TA in this truck sure has been a good one. Purchased new by my uncle and ran lowboy for many years till retired. Still doesn't burn any oil. Governors were the most cantankerous things I found once the aged but overall a very reliable engine for him.

This one was a "Fuel Squeezer" and I did away with that mess several years ago to more conventional settings. It still runs very well. This is bringing it home to the shop a few years ago to be used as a "yard horse:

20181209_090340_resized.jpg

20181209_132114_resized.jpg

Had a stuck injector so a quick pressure wash to remove a large nest built atop the engine:

20181217_144111_resized.jpg

Removed the original 9A90 injector loose and freed it up on the bench, reinstalled, and it runs well. Have a newly rebuilt set of 9B90 injectors to install but haven't yet. Wish the truck were in better shape but busted up and worn out is a fitting statement:

20181101_112138_resized.jpg
 

8V71

Well-Known Member
Joined
Aug 16, 2019
Messages
155
Location
Fresno CA
The bottom end is pretty straightforward. The critical areas are the Pistons/rings the proper compressor sleeve is a pretty important tool to have because of the oil scraper ring on the bottom of the skirt. They are very brittle and easy to break. They are different colored expander springs for the scrapers for different engine load applications, but the most important thing there is to make sure the ends of the springs are not overlapped when the rings go on or you will break them. There is a tool also to set the wrist pin plugs and definitely wanna vacuum pump to check those after installed or it will burn oil if they leak crosshead, pistons are slightly different.rebuilding the blower, shimming and adjusting the rotor clearance is critical and the blower seals. The governor is another area properly setting the governor is critical. Being it’s in a truck it’s probably a variable, speed, double weight, governor. There’s a couple tools for that but you can get away with setting them without the tooling. Some special wrenches to adjust the overhead are handy to have. Synchronizing the injector rack, will be frustrating and time consuming if it’s your first one.you probably want the proper injector height timing pin, there are a few different ones depending on the injector tag code. But you can also use a depth micrometer or calipers in a pinch.
Like was said before lots little tricks, there are also a few things when setting the heads on. And remember to mark and document on tear down like what bolts have copper washers and where they go. Those engines were so versatile in their applications so it’s important to put all the right length of bolts back where they went different plugs and all the different drive accessories, etc.. Good luck if you decide to tackle it and I think there are enough Jimmy Guys here to help you through it.
 

Truck Shop

Senior Member
Joined
Dec 7, 2015
Messages
17,008
Location
WWW.

You can't beat it--for the simple fact there will be a ton of incidentals to repair/replace while
swapping engine--how's that radiator? Clutch? Motor Mounts, starter, all the hoses, other wise
end up with too much invested doing a rebuild for a water truck.
 

Vetech63

Senior Member
Joined
Aug 10, 2016
Messages
6,440
Location
Oklahoma
How many labor hours would you estimate would it take to do a full overhaul on this engine not including removal/installation?
10 hours per cylinder.....but that includes complete teardown, vatting, and machine work if necessary.
What kind of special tooling is required for these engines, estimated cost of tooling?
A ring compressor is a must, the sleeve type is the most efficient. The timing tools for the overhead are a must..............not sure on the costs.
Things to look for when preforming overhaul, where could I source literature for this motor, and any other information you all think might be helpful would be greatly appreciated.
A service/repair manual is nice to have but if you have no experience in these engines the instructions can be complicated and confusing. It can be explained a lot better here with experienced professionals.
 

HTEoregon

Member
Joined
Jan 5, 2024
Messages
15
Location
Oregon
Is an inframe rebuild not a consideration?
Sorry for the late reply, been so busy between starting my business and work. I appreciate the info. I don't know if an inframe is an option, someone with more experience than I could say for sure. The engine bay on the truck is extremely tight, unsure if it would have the space needed.
 

HTEoregon

Member
Joined
Jan 5, 2024
Messages
15
Location
Oregon
Thank you! That was very informative. It's starting to sound like I should pass on this job. I don't think the cost of tooling and extra labor from learning and risk of mistakes isn't worth it for me. I appreciate you giving me all the good info though.
The bottom end is pretty straightforward. The critical areas are the Pistons/rings the proper compressor sleeve is a pretty important tool to have because of the oil scraper ring on the bottom of the skirt. They are very brittle and easy to break. They are different colored expander springs for the scrapers for different engine load applications, but the most important thing there is to make sure the ends of the springs are not overlapped when the rings go on or you will break them. There is a tool also to set the wrist pin plugs and definitely wanna vacuum pump to check those after installed or it will burn oil if they leak crosshead, pistons are slightly different.rebuilding the blower, shimming and adjusting the rotor clearance is critical and the blower seals. The governor is another area properly setting the governor is critical. Being it’s in a truck it’s probably a variable, speed, double weight, governor. There’s a couple tools for that but you can get away with setting them without the tooling. Some special wrenches to adjust the overhead are handy to have. Synchronizing the injector rack, will be frustrating and time consuming if it’s your first one.you probably want the proper injector height timing pin, there are a few different ones depending on the injector tag code. But you can also use a depth micrometer or calipers in a pinch.
Like was said before lots little tricks, there are also a few things when setting the heads on. And remember to mark and document on tear down like what bolts have copper washers and where they go. Those engines were so versatile in their applications so it’s important to put all the right length of bolts back where they went different plugs and all the different drive accessories, etc.. Good luck if you decide to tackle it and I think there are enough Jimmy Guys here to help you through it.
 
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