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+--- Thread: Idea: emergency full pull (/showthread.php?tid=857)
Idea: emergency full pull - CID Vicious - 11-18-2009
Since runaway is a feared problem and I'm assuming could possibly rear its ugly head when one is behind the wheel or when the hood is closed, I thought of having a driver accessible emergency pull.
One could get a handle out of the junkyard (Japanese mini trucks might be a good source) and mount it somewhere within your reach when at the wheel.
A cable or even solid wire could be used to grip the soft line. For use when tuning or anytime when the tuning is questionable, basically you'd either leave the line loose or finely adjust the clamp so that X amount of pull will pull the hose but it won't vibrate loose or leak. There might be a quick disconnect connector that we could adapt from the hot rod/race realm that would work better.
Or, maybe a cutoff valve with the same idea, accessible from the driver's seat. That would involve cutting and/or diverting the stock line, though.
I think it would be a worthwhile precaution to take before pump tuning begins, after all, what would the parts and labor be compared to losing an engine?
RE: Idea: emergency full pull - ForcedInduction - 11-18-2009
(11-18-2009, 03:56 PM)CID Vicious A cable or even solid wire could be used to grip the soft line.A true runaway is rarely from the injection pump. If the pump is mistuned, it will more than likely go when the engine is first started or the first time its revved. Jammed linkage is no problem, the governor will keep it at redline without harm (unless you've set the max speed set ridiculously high).
A true runaway from increased performance is far more likely to be from a fragged turbo or its seals. My GT22 is right around 180,000rpm at 18psi at redline, for example. Cutting off fuel will do little to stop the engine at that point.
http://www.youtube.com/watch?v=q4fxjKnuI4Y
http://www.youtube.com/watch?v=WmkHTkmj2_U
I'm not very worried about runaway. I keep tabs on my turbo's condition and I make sure to tune within known safe limits whenever possible (I don't just set boost and go, I plot it all out to make sure I'm not going to overspeed or surge damage the turbo). If I were to make an emergency kill on the cheap, I'd get a big V8 or V12 throttle body from a g@sser. They naturally spring closed, so all that would be needed is a normally extended solenoid or a pin on a cable. A few months ago I came across a BMW V12 in the junkyard that had a very nice 3" TB with no bleed hole that (as far as I could see) sealed completely when closed. I doubt a junkyard would charge more than $15 for one if you remove the position sensor.
A Garrett turbos have a restriction orifice in the oil supply line, so creating high vacuum in the inlet with a blown oil seal would not oil hydrolock the engine, especially if you have an intercooler.
RE: Idea: emergency full pull - 2.5-10 - 11-19-2009
if the turbo goes, and it starts to runaway, will the engine be able to spin faster than the governor would normally allow the engine to spin?
shoving something in the intake (towel, etc) would work correct?
agreed on the big TB as an emergency cut off too makes good sense if thats a worry.
makes me a little nervous about my turbo now, up on 300K miles hope it doesnt decide to fail anytime soon.
RE: Idea: emergency full pull - Einar - 11-19-2009
YES, it`s only the valves that is limiting the max engine speed(and the oil supply).
On an old engine the valves often act as rev-limiter(gasoline), but a diesel may not have this, it`s the valve springs, harder springs, more engine revs...