Runaway Diesels Do's And Don'ts

[DaveBen]

What can be done to prevent a runaway?

Stay away from external fuel sources, like a leaking gas (natural gas) line (caused my runaway). Be aware of what it takes to cause a runaway, like pouring fuel into the intake and don't do it. As Icanfixall just said. You can explode your engine.

Dave

 

[homelessduck]

I have thought about using an exhaust brake inline with the intake or just a simple mechanical pull with a throttle type plate.. One of these days I am going to play around with it.

 

[AcIdBuRn02ZTS]

Or just use a blast gate for the proper tube size. Thats what most pulling trucks use... very cheap and very effective. They make mechanical and electronic versions of all different sizes.

 

[fsmyth]

Work on more than a few Detroits. You will learn quickly.
Take a page from their book - add a flapper valve (factory on anything with a blower).
Killing the air supply works even if it is running on it's own oil. As long as there is not
a broken intake or blown gasket.

 

[chris142]

Too much crankcase oil from Jiffy boob can get sucked past the rings and cause it. The Op had a tractor on its side so oil was getting past the rings.

 

[CDX825]

Don't use a dry chemical fire extinguisher unless you want to completely rebuild the engine.

 

[The Warden]

I imagine the heat built up in the cylinders in the event of a runaway with the sudden addition of extremely cold co2 would cause some catastrophic damage of it own. Like cracked, well, everything.

Don't use a dry chemical fire extinguisher unless you want to completely rebuild the engine.

Both of these are good points, but IMHO even while understanding that using a fire extinguisher could ruin the engine, it's still good to have as a backup in case you can't block the intake for whatever reason. Keep in mind that a runaway engine can literally explode and do damage up to and including hurting people.

I've seen the flap to kill the air supply on a two-stroke Detroit...thank the diesel gods I've never had to use one, but IMHO it would be a good idea on any diesel just in case. Another thing I've done is, when replacing the top cover on the injector pump (which can cause a runaway if it's installed incorrectly), I keep a set of bolt cutters handy to cut the fuel line if it tries to run away. Of course, that'll only work if it's a fuel system issue...if the engine starts drinking its own oil or if there's an external source of fuel (massive propane leak nearby, for example), the only way you're killing that engine is by eliminating its oxygen source, or physically stopping the engine (i.e. dumping the clutch in high gear with brakes FIRMLY applied)...

 

[fsmyth]

Best thing to do - don't let it happen.
In 50 years, (I am 65, started early), I have not had one run away.
I HAVE had some run backwards. Scared me silly the first time

And have you ever tried to get a heavy duty transmission in gear while the engine is
at speed? Take your pick - engine or transmission. One of them is toast.
And if you DO manage to get it in gear, and you grab a low gear in the excitement,
the truck is going to MOVE. Brakes or no.

 

[IDIoit]

https://www.youtube.com/watch?v=3NRaqgab0_w

 

[crash-harris]

Hehe, I still watch that one for entertainment His reaction is priceless, but honestly he does a good job. I would use a hockey puck or piece of wood though.

 

[DaveBen]

You use what you have handy. No time to go back to the shop and find something better. It did the job!

Dave

 

[IDIoit]

now i really want my M37 done lol

 

[OLDBULL8]

Funny story about a Detroit 8V71. Maybe not funny but interesting.
I sold my 67 GM 35' bus that I had converted into a Motorhome to a guy from SanDiego. I get a call from him when he was in AZ. he and his buddy had just stopped at a rest stop and where going down the road.

Him, hey Bill this thing is smoking black smoke and won't go over 25 MPH.

Me, Are you on the road now?

Him, Yeah, we just stopped at a rest stop and this damn thing just won't go.

Me, pull over as quick as you can, and shut it off.

Him, OK where stopped but it won't turn off.

Me, he's trying to stop it with the wrong switch. Did he use the Emergency Stop.

Him, OK it stopped, now what do we do. Yeah Jack did stop it with the Emerg. stop switch.

Me, now go around and open the back engine bay door.

Him, OK got the door open, now what?

Me. Ya see that little handle on the upper left side with a solenoid.

Him, Yeah.

Me, well lift it up so that it latches and stays there, it shuts off the air if you have a runaway engine like I showed you guys before. Tell Jack to start it up. If it starts and no smoke, close the door and be on your way.

Him, OK, Jack started it and it's running perfect now. I'll close the door. Thanks Bill. We did have a little trouble getting it started after we stopped.

My question is. Tripping that door if indeed they would have had a runaway engine, I don't know if it would have stopped that engine. Since they where able to start it and run down the road. They have since put a 6V92 turbo in it. Said it really climbs the mountains now.

 

[crash-harris]

You use what you have handy. No time to go back to the shop and find something better. It did the job!

Dave

I think it would be in any diesel owners best interest to carry something to block off their intake in the vehicle. I know he was working on installing it though. Hence why I'll be making a wooden block to fit over the intake and brass nut. My 7.3L is N/A but better safe than sorry. Cable actuated intake flapper does seem like I good idea, particularly for turbo'd diesels.

 

[Waystro]

Really any engine can/will run away I carry singing to block the airflow(block of wood) even in my gas trucks. Yeah I'm