Running backwards?

[bchauvette]

Just read this in the S.E.E. operators manual. I've heard of diesel engines running backwards but not caused by improper rate of speed or gear selection. Do they mean lugging the engine?

"While loading bucket or pushing material, maintain proper gear range and
constant rate of speed. Failure to do so could result in engine running backward.
Indications for engine running backward are exhaust smoke coming from air
intake, oil pressure dropping to zero, lack of power, and transmission in reverse
of normal. Should this happen, immediately shut engine off, wait a few seconds,
and restart engine. Failure to shut engine off could cause damage to equipment"

 

[Recovry4x4]

While I can't speak intelligently for the MOG, I have experienced a multifuel running backwards at the 2008 GA Rally. Seems I bumped a stump at a low enough idle that it kicked the truck backwards and it started running backwards. I was aware of the ability to run backwards and because of that I was able to quickly stall it and start over but it surprised me quite a bit!

 

[doghead]

Amy once stalled a 2.5 ton truck and it started running backwards. Held the brakes to stall it.

 

[rchalmers3]

I had a Mog do that to me: I took a steep climb and ran out of power. When the engine stalled I was unable to hold the truck using the brake. It was very confusing to lose control of the truck, have it sliding backwards and hearing the engine running (poorly) and billowing smoke out of the snorkel.

rick

 

[Case406]

Smoke out of the snorkel? That reminds me of a thread on Unimog BenzWorld..... I still can't believe it.
Rolf

 

[tennmogger]

Smoke out of the snorkel? That reminds me of a thread on Unimog BenzWorld..... I still can't believe it.
Rolf

That might have been my post on Benzworld. Had that happen just as described above, engine bumped backwards while using the front loader on a 406. The engine sounds just fine and at a low idle it takes a few seconds to notice the exhaust out the intake. In the meantime it is a shock when 'forward'...isn't.

 

[Case406]

Bob,
there was a picture attached to it on BenzWorld. Was that you?
Cheers Rolf

 

[bchauvette]

What really scares me is the zero oil pressure. But I guess you find out sooner or later the engine is running backwards.

 

[Hummerdave]

I remember older mercedes passenger car engines doing that.. when it happened, the engine would "run away" because the injection pump governor could not control the speed in that condition.. really scary.. the only way to kill it would be to drop it in gear and dump the clutch with brakes on (which you can't do with an auto trans) or put something solid over the exhaust to shut off the air or start loosening the injector lines if you didn't mind being that close to the engine.. I'm guessing these om352's wouldn't get to this point...
Dave

 

[61sleepercab]

Just as bad is diesel running off on combustible fumes such as dozer or backhoe rupturing gas line and diesel starts running on fumes with no way to throttle down but get equipment out of gas cloud . Same idea happens with the gas soaked rag over the intake to start a diesel. Mark

 

[rchalmers3]

The OM352 is a long stroke motor, so it may not compare favorably to the shorter stroke civvy car engine. In my case described above, I was able to dump the clutch and stall the engine, but that was after a few seconds (it seemed like a minute!) of confusion and assessment of the situation.

Rick

 

[Another Ahab]

The OM352 is a long stroke motor, so it may not compare favorably to the shorter stroke civvy car engine. In my case described above, I was able to dump the clutch and stall the engine, but that was after a few seconds (it seemed like a minute!) of confusion and assessment of the situation.

Rick

If you want to get your blood pressure up, I bet a runaway engine is a great way to start.

 

[phil2968]

Just as bad is diesel running off on combustible fumes...

The fire engine that my brother drives has an air intake valve that will close if the engine runs away.

 

[bchauvette]

The fire engine that my brother drives has an air intake valve that will close if the engine runs away.

I had a Detroit 8V71 that had a spring loaded flap above the blower to block intake air in case of a run-away. It was engaged by a dash mounted emergency push button. I heard that on a worn engine it could run on oil bypassing the rings.

 

[Another Ahab]

The fire engine that my brother drives has an air intake valve that will close if the engine runs away.

I had a Detroit 8V71 that had a spring loaded flap above the blower to block intake air in case of a run-away. It was engaged by a dash mounted emergency push button. I heard that on a worn engine it could run on oil bypassing the rings.

Considering the threat to life-and-limb of a runaway, you'd think manufacturers would automatically include some kind of feature like these for the problem; neither one seems complicated or even costly.

But...this isn't anything like a perfect world though, is it!?

 

[bchauvette]

I was given strong instruction when first starting a diesel that had IP or injector work to have the air intake readily accessible and a large rag to block intake should things go south.

 

[Floridianson]

Don't use a rag that's for shure.

 

[bchauvette]

Don't use a rag that's for shure.

Why? Concerned it will get sucked in? I'm talking Turkish Towel kind of rag in a code red situation.

 

[Hummerdave]

Well, don't forget that if the engine is running backwards, exhaust will be coming out of the intake and a guy could get a badly burned hand real quick.. the exhaust pipe will be the intake, so that would be the one to block off.. I saw a red shop rag go thru an engine once.. came out the other end in piles of red threads..
Dave

 

[frodobaggins]

Considering the threat to life-and-limb of a runaway, you'd think manufacturers would automatically include some kind of feature like these for the problem; neither one seems complicated or even costly.

But...this isn't anything like a perfect world though, is it!?

Nope, but check out Hanksdeuce's solution:

http://www.steelsoldiers.com/showth...ore-Project!&p=1636834&viewfull=1#post1636834

Pretty nifty.