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!
Just buy a reman--unless you or others are in no hurry. Manuals for sale on Ebay. Not hard to work on just messy, and will require a few special tools--so for expense sake it's easier to buy a swing engine. Others will have all sorts of comments.
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.
Buy a used engine somewhere or replace with a modern engine, they are not worth their weight in scrap when they need big repairs. Removal and install might be fun as that cab is tight
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.
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$3,750 for a good used running engine, I doubt you could buy the parts for an overhaul for less than that. If yours is slobbering that much oil then you'll definitely need piston and liners.
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.
save old engine to practice on and do the reman, you might not get your core charge back tho
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: Had a stuck injector so a quick pressure wash to remove a large nest built atop the engine: 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:
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.
Detroit 6v92t Engine Assembly for sale on HeavyTruckParts.Net Detroit 6v92t Engine Assembly on HeavyTruckParts.Net. Easily find what you need from 2,648,799 parts available. www.heavytruckparts.net 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.
Machine work is another factor. It may need a line bore, head/block surfacing, new ring gear, and who knows what else. Until disassembly and inspection there is no real, way to put out a rebuild cost.
You know it does, it's a given on old engines.
10 hours per cylinder.....but that includes complete teardown, vatting, and machine work if necessary. 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. 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.
Is an inframe rebuild not a consideration?
Fact.
Detroit 2 stroke engines were popular in older work boats. Look on line for "Boats and Harbors" they have a digital version of their for sale paper. Towards the back are non display ads for engines, you will find rebuilders and engines there.
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.
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.
Nobody knows how to work on these junk engines anymore, one consideration is that you would be able to learn how to work on them. I would also recommend to the owner not to take it to mechanic they will just mess it up.
In my opinion Detroits are probably one of the worst engines to run at light loads, which I think being this is a water truck might be some of the problem.
Yes they are very tight in the vehicle. We used to in frame them all the time back in the day. Two of the most difficultthings that you will probably have is = setting governer fuel rack. If the rack is not set right the engine will run away and may not shut off. Causing major damage to engine. Reinstalling the heads is another thing that will need to be carefully completed. As they used square o-rings for sealing the heads. One misplaced o-ring and you will have a leak of coolant or engine oil. Lancer
2-stroke love full throttle = oil and military used these engine for more that 30yrs. Never idle a 2-stroke detriot and only use non detergent 30w or 40 motor oil. 15w40 will wipe the rings out from the detergent in the multi vis oil Lancer
not very may of us left that still work on 2-stroke detroits Lancer
Our 6-71 gets Chevron Delo 100 40w, seems to like that…
If you find the correct spec ashless 40 weight engine oil they run a lot better it's very strange but you definitely see a difference before and after
When I worked for the Detroit distributor back in the 70's it was always and only 30 wt Delo. No idling and drive it like you just slammed your hand in the door and take it out on the truck. The trick with the rack is to keep it adjusted so all the injector arms roll over at the same time. If one is over tightened, the rest become too loose.
The entire fueling set up is critical for proper operation and maximum power. The governor has to be in the right full fuel position in relation to the injector full load. The types of governors will make a difference in the procedure itself. It's an art to do an injector height and fuel rack adjustment correctly along with the governor, buffer screw, idle adjustment, and full load rpm in relation to the position of the yield link. I would suggest you get a service book or have someone that has some decent experience with Detroit engines. A wrong setting can be a disaster on those engines.
What Ed Strogh would say, it was said he wore Alpine green undies.