emergency stop solenoid

[bevans6]

So I'm poking around the top of the 8V71 looking for air leaks, and I see that the emergency stop solenoid wire is disconnected.  Since I have heard horror stories about both runaway engines and the negative effects on blower seals from tripping the air valve, I decided to research the deal.  The search function brought up a recommendation from DD at some point that the air flapper valve solenoid be disconnected.  The discussion went on about using a remote control ball valve to shut off fuel flow, using a rod welded to the governor to push and shut off fuel flow, how the engine stop switch won't work if the air pressure is too low, how the engine can run on a oil leak so the whole shut off the fuel flow thing is moot, on and on and no conclusion that I can come to, except that I truly have no clue about how this engine works! 

Should I or should I not connect up the emergency stop solenoid?  let the debate begin!

Brian

[gumpy]

You should.

[Tony LEE]

"brought up a recommendation from DD at some point that the air flapper valve solenoid be disconnected"

A URL to this would be useful because the recommendation may be conditional in that it only applies to engines beyond a particular serial number or with a particular injector system.

If it has no other use, it does make for an effective anti-theft measure.

[Ed Hackenbruch]

So if an engine starts running on an oil leak making the fuel shutoff moot, isn't the only way to shut it down is to shut off the air intake?

[luvrbus]

If your 8v71 is equipped with the new style single screw adjustment and spring loaded fuel rod there is really not a need for it this is the way the 92 series are set up but some 92 series have the emergency shut down also.
Fwiw in the later years of production the 71 series didn't use the shutdown   good luck

[bevans6]

Here is the previous discussion:

http://www.busconversions.com/bbs/index.php?topic=928.0

The thought was that activating the emergency shutdown flapper actually caused the oil leak that would make the engine continue to run.  I think.  Not quite sure how it did that with no air.  I'm thinking big bottle of halon in the intake would kill it pretty fast!  Or argon, or whatever inert gas you had handy.

edit again:  Blowing the blower seals would allow both air and oil in, sucked in by the positive air displacement of the blower itself turning. According to my flimsy logic anyway.  

1980 8V71 - what kind of rack screws would it have?  Fuel rods?
Brian

[bevans6]

I phoned Harper, the local DD service agent and dealer, and talked to the shop supervisor.  he said if it's disconnected he would leave it disconnected.  he told me that if the flap hangs up at all or doesn't make a good enough seal (and it is known to do just that), it allows the engine to continue to run long enough to pull the seals in on the blower and then the engine runs away on engine oil.  He said just put a solenoid valve in the fuel line.  he said if it's been disconnected for some years, that he wouldn't hook it up without taking it off and rebuilding it, and replacing the solenoid anyway.

So I will leave well enough alone.

Brian

[Ed Hackenbruch]

Sounds like sound advice to me.   guess i better go take a closer look at mine and see if i have the air shutoff or not.

[BG6]

Dunno about anyone else, but I have seen what happens when a Diesel engine starts sucking in gasoline fumes.  I was 8 miles away when I saw it.  It has left an impression to this day, 15 years later.

This is an EMERGENCY shutdown device.  You would use it as a last resort, when there aren't a whole lot of other options left.  At that point, I'm willing to fry a turbocharger rather than burning the whole coach to the ground.

On a non-turbo engine, I can't think of a reason that I wouldn't want it.

If it hasn't been used for a while, get it operational, and test it once a month (on a turbo engine, test it by starting the engine cold, running for 30 seconds, then hit the switch before the turbo gets hot).

[Dallas]

Watch the Tach on this one.

8V71N

[Dallas]

Wanna get close enough to close the flap?

Detroit Diesel Meltdown

[Dreamscape]

I'll pass on that one, I would have left a stain on the concrete!