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Discussion Starter #1
So, I know there's the mechanical shuttle valve shutdowns to kill air to turbo in case of diesel runaway. Problem is they're kinda proud of them: PRICEY!

From what I hear the stock manual shutdown won't do the job, because engine is fueling so hard that flipping shutdown just rips the rubber tip off of solenoid valve and the engine roars on.

I have a nice 1/2" ball valve, one of the 1/2 turn type. Picked up a couple of 3/8" hose nipples at the hardware and planning to plumb the valve into my vinyl fuel line, just before lift pump.

Obviously an engine would run a few more seconds before fuel starvation killed it, but a fairly quick way to stop runaway, I hope? Engine would still be pumping oil so bearings and cylinders shouldn't be damaged by fuel starvation, but hope it wouldn't draw crankcase oil to run on.

What do ya think: work, or not work?
 

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Jimmy,
I'm not sure how long a VE pumped 4bt would run when it goes into a runaway condition, but a 6.2 GM with a Stanadyne pump will run long enough for the engine to self destruct! I think that would also be the case with the VE pumped engine also, because there is a substantial amount of fuel available in the pump. It would only take a few seconds for the engine to go over 4100 RPM. At this RPM even if you have 60lb. valve springs the valves will float and cause damage. I think the engine would run long enough without fuel from the lift pump for that to happen.
If it goes past 5000 RPMS, it could result in serious bottom end damage.
On my little 4WD diesel tractor, it has a simple little inline device in the intake plumbing with a cable operated butterfly that shuts off the intake air. You could have something like this in the intake system before the air filter (if your filter box and associated plumbing is well sealed) as an emergency shutoff. You might suck some oil through the turbo compressor section seal when you activate the shutoff, but it probably wouldn't cause much or any damage, compared to the damage that you would incur in a runaway situation. It really wouldn't take much to machine one up.
Bob B.
 

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I have heard it is possible for the engine to start consuming oil and continue to run on, but I dont know if that is really possible. I have been told an air shut off is the only sure deal....again, not sure.
 

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If it's a manual how about just putting it in high gear with the brakes on???? Might hurt the clutch, but I'd think it'd stop the engine unless the clutch wasn't up to par.
 

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I have heard it is possible for the engine to start consuming oil and continue to run on, but I dont know if that is really possible. I have been told an air shut off is the only sure deal....again, not sure.
Yes a diesel can run on crankcase oil. Doesn't happen often though. Some of the gas well and oil well drilling rigs around here have gone into runaway when they hit a pocket of natural gas. All the rigs have emergency shutoff mechanisms on them for this reason. They tell me that the sound or a Detroit in a runaway situation is awesome.:D (As the operators are running for their lives) :nuke: Shutting off the air is the only foolproof way to do an emergency shutdown.
Bob B.
 

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Still better to kill the air... There are cheep ways to do it, if your crafty enough..;) depending on size and location you could have a cable that drops a exaust "flapper" to pinch of the intake tube, etc, etc. It all depends on your setup, and what you can pull out of your booty. If ya want I could machine ya gulitine but it will cost ya a bag of yellow M&Ms...LOL :happyfinger:
 

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In a Diesel Runaway, a True Runaway is caused by a fuel source other than your diesel fuel. This is why the governor cant hold down the R's and you cant shut it down with the electric fuel shut off or the manual shut off. The only way to stop a 'True' runaway is to kill the air.

A 'True' runaway can be caused by driving into a combustible vapor atmosphere, blown seal on your turbo feeding engine oil to the air intake, broken rings allowing oil to be ingested past the pistons. These are runaway conditions. The engine will come up to max RPM and keep right on climbing until it blows up. And in most cases you dont want to be next to it when it blows.

Now engine over speed is a different issue. Improper adjustment of the IP pump/governor could allow the engine to over speed, but a shut down of the diesel fuel will stop it as no external fuel source is causing the overspeed. Of course in a over speed, an emergency air shutdown would also stop it.

I use emergency shut down on my engines.....just in case. If you get a 'True' runaway, it all happens in seconds. If you can do an immediate shutdown, Your engine is intact and saved. You only need to find the source of the external fuel causing the runaway. It could be as simple as a turbo seal and you saved your engine.

Just keep in mind that a 'True' runaway is totally different than a over speed condition.

Paul
 

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Discussion Starter #8
Very good info and feedbak, guys, thanks! I'll see if the hardware store will give a refund :~ )

I like the guillotine valve, may look at fabbing one up, can't be THAT complicated! Might even check a truck wreckers next time I hit the big city!
 

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I think it would be easy to just make an adapter for an EFI throttle body in the intake path. They all have a spring to return them to idle, you just need to make a trip mechanism that will allow it to close. They also have a small hole in the throttle blade, but the engine can't run fast on what gets through that tiny hole. You could always plug it with a rivet.
 

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Are we talkin 4 53's? Or 4bt's?
 

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By shutting off the air at high speeds there is a chance you can damage the turbo seals. In a Detroit there is a really good chance you mess up the blower seals. Most Detroits, well unturbocharged ones, and a few that are turbocharged, have an air flapper valve for use in an emergency so you don't have a "green grenade" :nuke:

The safest and an absolutely harmless way to kill a runaway is to feed it CO2 from a fire extinguisher, no seal problems afterwords.
I would test it once with the engine on the governor just to be sure you have a plenty big enough extinguisher. It could be permanently mounted and plumbed with a pull cable to open the valve in an emergency, somewhat like they use in a nascar car, or in a restaurant near the grill.

Grigg
 

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Discussion Starter #13
Hmmm, that might be the best idea, Grigg!

I have an 'in' on anything to do with fire protection and can get any of that stuff cheap or free. I've got some CO2's & Halon already, but only about 5lbs size. I'd want at least a 20 for a good long continuous blast. Dumb easy to plumb it in, and simple to rig a solenoid gas valve.

Matter of fact, many CO2's have a separate CO2 charge cannister, about the size of a throw-away propane cylinder, rechargeable! Thanks, I'll look into that.

Thanks to all!
 

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So would rigging it up like a nitrous shot post turbo/pre-intake be the best route? That's not something I'd think would be too good to be blowing through the turbo, no? Cause that would be very simplistic to setup. You could even have the tank in the cab for easy access and a solenoid switch on the dash to actuate it.
 

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How about putting the 3" ball valve between turbo and intake instead... Shuts it off, doesn't kill turbo seals. (Might put it into surge, though.. But nothing is perfect.)
 

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For a really thorough emergency shutdown install, how about a combination?

CO2 to get it slowed down after it takes off, then an air cut-off to stop it. This way intake piping, turbo seals, and/or blower seals for us Detroit nuts, etc would not have to withstand a full-on high speed shutdown via air cut-off.

K204DR, my thoughts exactly, a large ball valve. And yes, a rebuild of external components is preferable to an engine rebuild or worse, sunshine getting inside the block.

Ken
 

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lol a cut out on the intake with the end shut off. a peace of wood over the turbo. why would the engine run away? have you been abusive to her? lol:happyfinger: :happyfinger:
 

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The CO2 wouldn't slow it down, it'd stop it instantly.
It'd stop the combustion, but from high revs the engine (and attached load) might take longer to spin down than the CO2 shot lasts.
If it's still spinning fast enough when the CO2 runs out then it could restart.

I've had my engine running on it's own oil before. It was it's last run before a rebuild and was in poor enough condition to drink 1 litre of oil per 100km. I would run it up a hill and EGT's would climb past about 600, I'd back off and it kept going.
I pulled over, clutched in and it was still running about 2000rpm, but as it cooled down it lost compression and stopped.
Then I could start it again on diesel and drive slowly on.
 
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