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Discussion Starter #1 (Edited)
We had an engine runaway at the shop today, this a navistar maxxforce 13 liter Diesel engine, it originally had a failed turbo that pushed so much oil in the charge air cooler (intercooler) and all through out the engine, the tech that worked on it replaced the turbo and cleaned the piping, he also removed the injectors and siphoned out all the oil that was in the cylinders, afterwards he tried to start it and it ran away so we expected that there's probably a bit more oil in the intake manifold which is built into the cylinder head, apparently there was a LOT more oil in the intake manifold and the engine ranaway backwards, yes backwards! It was pretty scary but I was able to save it and stop the engine, crazy day! By the way the injector harness was disconnected when that happened and the key was not in the ignition, it basically ran on the oil in the intake because of the high compression in diesel engines
Anyone else here ever had a runaway? I also had another runaway 5 years ago and I ran away from the truck and the engine blew up
Here's a video of what happened!

 

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Yep, some years ago when I was doing engineering test work for General Motors I had a 16V149 Detroit (that's 2,384 cubic inches and about 1,400 horsepower!) take off in a test cell ingesting it's own oil. Had to go in and manually throw the blower valve to choke it's air. Talk about a "pucker moment" :eek:

Jeff
 

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Discussion Starter #3
Haha I know exactly what you're talking about! That stuff is no joke, I worked at the railroad and a couple of years ago we had an EMD engine blowup because of too much crankcase pressure that engine is 710 cubic inches PER cylinder, it's a 16 cylinder engine so that makes it an 11,360 cubic inches engine :surprise:

Yep, some years ago when I was doing engineering test work for General Motors I had a 16V149 Detroit (that's 2,384 cubic inches and about 1,400 horsepower!) take off in a test cell ingesting it's own oil. Had to go in and manually throw the blower valve to choke it's air. Talk about a "pucker moment" :eek:

Jeff
 

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Yep! Had it happen on a sizable indoor generator. Nothing I could do but GTFO as she screamed her way to BOOM, SCREACH, HALT...
 

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Discussion Starter #5
By far one of the scariest things ever, when I had a runaway 5 years ago I did the same thing and went into the service managers office screaming IT BLEW UP JEFF! hahah the look on his face was priceless

Yep! Had it happen on a sizable indoor generator. Nothing I could do but GTFO as she screamed her way to BOOM, SCREACH, HALT...
 

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If the engine runs backwards, there's no oil pressure?
 

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Discussion Starter #7 (Edited)
Really interesting question, I don't have an answer that I know for a fact that it's right, as far as I can tell is that it would be able to build oil pressure but I'm not 100% positive about that. I'll have to look more into that and definitely a good question!

If the engine runs backwards, there's no oil pressure?
 

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If the engine runs backwards, there's no oil pressure?
They aren't running on mechanically pressurized oil Greg...the condition can be caused by excessive blowby which pressurizes the crankcase and allows oil to be drawn into the intake through breather piping. At that point they're running their own crankcase oil and the only way to shut them down is to choke off the air supply (or wait for it to blow up!)

Jeff
 

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I get that it's abnormally burning engine for fuel in the video but if the engine is truly running the wrong direction, the oil pump is running the wrong direction and will push toward the oil pickup instead if sucking through the oil pickup, right?
 

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I get that it's abnormally burning engine for fuel in the video but if the engine is truly running the wrong direction, the oil pump is running the wrong direction and will push toward the oil pickup instead if sucking through the oil pickup, right?
Yes, but if its a runaway that doesn't make a damn bit of difference. An engine can run for an amazing amount of time with no oil.
 

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A 4 stroke won't run backwards so this must be a two stroke desiel engine?
 

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Discussion Starter #12
This is a 4 stroke engine.
You know another person said the same exact thing you just said about a 4 stroke can't run backwards, but how do you explain the fact that I'm trying to block the intake and it's pushing me away? Earlier before that video it was about to runaway and I used that same piece of mudflap and it instantly got sucked onto the intake and chocked the engine

A 4 stroke won't run backwards so this must be a two stroke desiel engine?
 

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If the exhaust system was full of oil, the 4 stoke deisel could run backwards on that oil because the exhaust becomes the intake source and the intake becomes the exhaust. The deisel is particularly suited because unlike gas deisel doesn't care much about air fuel ratio or need spark timing
 

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Navy Engineman "A" school --- 1971
Detroit / GMC 6-71 on a test stand
Punctured blower seal
Took off running forward... I cut off the fuel and it slowed down to a 4-500 RPM grunt and shook like crazy for about 30 seconds - we thought it would die. Suddendly she bellered and started gaining RPM rapidly. There was no air intake shut-off and no screen over the impellers of the blower. Took a couple inch thick shop manual and slapped it over the intake. It again started shaking and slowed waaaaay down - thought we had it then. Until the shop manual slipped, buckled and started getting eaten by the impellers. She was over 5,000 RPM (tach didn't go any higher) when the chief instructor pulled us from the dyno room.
I don't know for sure how high she was screaming but suspect over 7 when she self destructed. Fire, oil, fuel, metal everywhere. We killed off the flames pretty quickly and took the entire rest of the day and next to clean it all up.
Either the crank or block failed and the whole side of the block came out with the crank in three pieces. Scary was the right term.
We did everything we could have done - so we thought.
Chief instructor said that the one thing we didn't do was a suicide mission to dive underneath it and yank the drain plug to let 24qts of oil drain out of her.
We were instructed that should this engine have been on a boat, it was expected of all of us that we would have pulled that plug to save the vessel and its crew.
 

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We only had soda-water extinguishers in the dyno room and classroom outside of there. We had a bunch of guys bring Purple-K (as I recall) from the dock and warehouse in the adjacent building. I think the extinguishers made a bigger mess than anything that the fire and oil did.
 

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Greg said
A 4 stroke won't run backwards so this must be a two stroke desiel engine?
I stared my Branson 40 hp diesel tractor once as it was parked on a slope. When I pushed in the clutch to start it, it started to roll. So I just slipped it into high gear and popped the clutch. It started up and then I noticed that the shuttle shift (Fwd to Rev) was in reverse when the engine started. Sure enough, when I tried to motivate the tractor, it went backward in forward gears and forward in reverse gears. I shut it down and restarted with the starter and back to normal. While running backwards the engine made more noise and didn't have any power. In retrospect, I guess that part of the low power backwards is because this engine is a 3 cyl turbo charged 4-stroke diesel. So, when running backwards, the turbo is also backwards and is sucking exhaust out of the intake and exhaust is blowing out through the air cleaner. I didn't check, but I bet that the air cleaner got a quick clean out when this happened.

I am retired from the Federal Aviation Administration (FAA). FAA has facilities all over the country that used diesel and other engine generators for back up power. The diesel generators are spec'd out to have "Air box shutdown" that is automatically activated when an uncontrolled over-speed condition is detected. This is facilitated by a spring loaded damper/throttle plate that slams shut when the engine won't respond to normal throttle commands ie run away condition.
 
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