I have an older Detroit 8v92. Here is her story she ran great last season after sitting for two months I started her up she idled for about ten minutes to warm up when I took off she ran away .I turned off the key and after what seemed like an hour but was only a few seconds the motor shut down. She had puked out a far amount of oil onto the ground but when it was restarted it ran fine.I drove her to the shop where she sat for a few more days when next she was started the motor seemed fine until I pulled her out to enter the shop again the motor ran away (turning it off didn't stop her).Acting on instinct I pushed in the clutch now I'm sitting on top of a screaming bomb getting ready to blow So I did the only thing I could I held my foot on the brake and let out the clutch .When the smoke settled the motor had stopped but not before twisting off the drive shaft and totally destroying the front differental:Banghead. The rear end parts were a straight forward fix and we found a stripped buffer screw on the governor probablly the cause of the ran away Now here is where I really need help the motor now will pour two gallons of oil out the exhaust in ten miles .Here is a list of what I have done so far.pulled the turbo,and blower all clean, top of the inter cooler is dry.Air box drains are open but the air galley is oil soaked Next we pulled the pistons cylinder walls look great vacum checked the wrist pin caps and then turned each piston upside down and filled them with fuel oil no leaks at all Also really looked over the heads found nothing. I would really appreciate any Help that anyone can offer.
The blower gasket between the block and blower on our 8-92 sprung a leak and went out the exhaust once. Did you see if there was a leak there?
I had an 8V92TA in an 86 Pete. Great motor and a clean motor if you know how to maintain them properly. Yeah...If the blower seals and rings are in good shape, it can be done. It's as simple as cleaning a few check valves. The airbox on a Detroit is where the blower "accumulates" the charge for scavenging and the new combustion cycle. The blower seals, as the blower ages, and turbo seals will eventually leak small amounts of oil, and the compression and then cooling of the air charge causes water to condense. The airbox drains allow this accumulated crud out of the airbox instead of having it sucked into the cylinders where it will cause abnormal or accelerated wear. On turbo motors there are check valves located at each drain; these must work properly. If they stick open or closed its bad news; many people neglect these service items. In fact, most people dont even know they exist. The check valves should be pulled and cleaned at every oil change. If you have a motor where Detroit routed them back to the oil pan (they did on some motors, as the EPA had a fit about the original design which just allowed the slop to go onto the road) you will do your engine a huge favor by removing that and routing them to a "crap can" that you then empty once in a while (at oil change intervals is a good choice.)
when you pulled heads were the exhaust ports wet with oil? how much oil was in air boxes? DDA's are never completley dry unless it's a new unused motor. Valve seals?
Most DD's I have ben around are equipped with two shutoffs. The normal one you use, and an Emergency Kill. This is usually a pull cable routed to the blower doors. They are held open with a little rocker on a spring. and when the rocker is pulled against the spring, the spring loaded doors slam shut, killing the air supply to the engine, killing it. once tripped, in order to restart, you have to manually open the door, and lock it behind the rocker that holds it open. This handy feature prevents that "time bomb" from winding up enough to hurt anything if acted on fast enough. Sadly, on many older engines, they get unhooked, or the cable is non functional. When I was in the oilfields, it was standard procedure to test them regularly to make sure they worked when needed. Wait till you hear a twin turboed 12V71 run away:jawdrop:spaz
still baffled The air box drains are open if you hold your hand in front of them you can feel the air and get a hand full of oil.When we pulled the heads there was standing oil in all of the piston dishes.As far as the emergency shut down goes it was offered as an option but not equiped on this motor. At this point the only thing we can think of is to reassemble her and hope that there was a leaking gasket or O-ring we couldn't see.It just seems that as nasty as detroit oil is it should leave a trial that we could follow:beatsme
V8-92 I dont have much experience, with the 92's, as I have with the 71's, but Ive never seen a correct set buffer screw, cause a engine to run away. A buffer screw, for the most part, just keeps the looping out of the engine. Its usually the last thing you set. Some of my guesses on the runaway problems, is 1. If the engine set, as you stated, the governor fly weights could have froze, Ive had it happen. It may happen the first time, the next time it may not, then the next time it will do it again. 2. injector maybe sticking, the rack (in the injector) could have corroded, causing it to stick 3. oil consumption, I would agree with the others, most likely blower seals, if youve checked the rest of the engine Im assuming, that after you took the engine apart, you then put it back together and it uses oil now. If so, was the engine put together correctly? I would strongly suggest, you find and install a emergency shutoff device. You should find these at any salvage yards, they should not cost that much, when a DD 71/92 runs away, they can suck engine oil out of the base and start to burn it, then it gets ugly. This is my 2 cents worth, if you PM I will give you a phone number to call, that will have the shutoff device and more information.
oil on pistons when you pull heads is common, it gets in there when you lift heads up, it comes from camshaft area, make sure NOTHING falls in by camshafts ie. nuts bolts washers... they will get jammed and break block. Injectors sticking, bent rack rod or sticking rack will cause runaway AND misadjusted BUFFER screw. The rod comming out of inj.should move freely,eg. if you hold inj. sideways with rod pointing up & extended and let go of rod it should fall in on its own or with a slight touch, and if you turn it over it should do the same. when it's all assembled without rack rods attached rack with 4inj's should move freely with very very verylittle pressure , like just touch it with your finger!!!! should be no binding or sticking for FULL travel of inj. ANOTHER thing older motors running on ULSD need fuel lube!!!! remember the old 5.7s &6.2& 6.9s when they changed fuel all the pump&inj problems. Now we are starting to see it with ULSD fuel, so untill all the stuff gets rebuilt with new & improved parts there will be fuel syst. failure.