is emergency shut-off really necessary?

lostagain · June 27, 2007, 06:55:09 AM

Can anyone give me a compelling reason to keep the emergency shut off on my 4-71 that I just turboed?
I have a temporary flex hose from the turbo compressor to the top of the shut down housing, but it is very short with a sharp 90*. Aukward set up. It would be easier, more space to connect to the blower intake flange. The engine shuts off from the dash or the back with the skinner valve. Or manually with the fuel cut off lever on the governor. Sure, the automatic shut off is good to have for overheat or low oil pressure situations, although I watch my gauges while driving. What if I had a stuck injector? Could I not shut it off with the lever on the governor? Any and all comments appreciated, thank you.

DrivingMissLazy · June 27, 2007, 07:10:00 AM

I can give you one good reason for keeping the emergency shutoff.
One night at O dark thirty I topped a California mountain pass in my 4104. I was in 2nd gear and with pedal to the metal. This was on a highway with little space to pull over for quite a ways. Anyhow, when I released the pressure on the throttle, the engine continued to roar at about 22-2300 rpm. There was definitely no place to pull over, get out and go to the back and try and find the governor release. A flash light would probably have been impossible to find. Even then, the problem was a stuck injector that was holding the rack of the 6-71 open. The only way to kill it, that I know of was the emergency shut down flap to cut off the air.

Anyhow, when I finally thought of it, I hit the emergency stop button and was thankful I had checked it out previously. I coasted down the mountain till I got to a pull over and got stopped before I run out of air. I had to actually remove the valve cover and unbolt the injector so that I could continue home on 5 cylinders.

And it did not do any harm to the blower seals as many have professed. In fact, I have never heard anyone say that they actually have experienced seal damage from using the emergency shut down. Mostly old wives tales of someone's brothers uncles son in law who had the problem. LOL
Richard

CS · June 27, 2007, 07:10:33 AM

Yes it is necessary, In the event of a "runnaway" without emergency shut down motor will over rev till self destruction, then you will have to buy new engine some surrounding goodies and a new seat cause the pucker will rip coushon.

superpickle · June 27, 2007, 07:27:10 AM

Quote from: CS on June 27, 2007, 07:10:33 AM
Yes it is necessary, In the event of a "runnaway" without emergency shut down motor will over rev till self destruction, then you will have to buy new engine some surrounding goodies and a new seat cause the pucker will rip coushon.

You probably will need a New Pucker string and a New Blankey as well..

The peeps I bought my Fishy from told me NEVER use the ESS, it will Blow up the engine..

I thought, What the heck is it Their for

TomC · June 27, 2007, 08:08:06 AM

Typically when turboing the engine, you remove the emergency shut off. But this also means you're replacing the injectors to the spring loaded turbo injectors. If you have not replaced the injectors, then keep the emergency shut off. Don Fairchild removed my emergency shut off (and you'll notice that factory turbo engines do not have emergency shut downs) and now I'm using the spare wire for my misting system. Good Luck, TomC

WEC4104 · June 27, 2007, 09:46:21 AM

I can't answer whether having a turboed engine makes a difference or not. But from first hand experience I can address the need for the shutdown switch to be operational on a standard 6-71. Check out my post from about a year ago:

http://www.busconversions.com/bbs/index.php?topic=1392.0

Also, I was always concerned about hitting the switch accidentally as I was driving. I have since installed a hinged cover over the toggle switch. (Available at auto parts stores for the boy racers)

DrivingMissLazy · June 27, 2007, 11:45:15 AM

Did you have any damaged seals after using the emergency shutdown? I know I did not and have not yet met anyone who has. Sure would like to see some definite confirmation that that action will damage blower seals.
Richard

Quote from: WEC4104 on June 27, 2007, 09:46:21 AM
I can't answer whether having a turboed engine makes a difference or not. But from first hand experience I can address the need for the shutdown switch to be operational on a standard 6-71. Check out my post from about a year ago:

http://www.busconversions.com/bbs/index.php?topic=1392.0

Also, I was always concerned about hitting the switch accidentally as I was driving. I have since installed a hinged cover over the toggle switch. (Available at auto parts stores for the boy racers)

WEC4104 · June 27, 2007, 11:56:51 AM

Richard -

My situation was when my E Shutdown wasn't operational, (but wished it was). Have never used it on a running engine.

lostagain · June 27, 2007, 01:03:12 PM

Thanks guys, great answers. Turns out just this morning I picked up a 4-71 in pieces from a friend who had it at his lumber mill. And (oh treasure

), the intake horn that mounts on the blower has the shut down flap at its base so it will be between it and the blower, therefore achieving what I was after... giving me the space I need to do a proper charge air connection with the hump connectors and hoses. So I will mount the solenoid onto the new location for the flap. Isn't it great how things work out at times. After reeding your answers, I will feel better being able to hit that emerg. switch from the dash. Thank you all. Great board. BTW I will likely be at Busnusa in Oregon. Looking forward to meeting some of you nuts in person.

buddydawg · June 27, 2007, 02:52:10 PM

What is the correct way to test the emergency shut off? Hearing how some do not want to use it for fear of hurting the engine it makes me nervous about testing the system. I would like it to be operational.

lostagain · June 27, 2007, 02:59:13 PM

Master switch on. Engine not running. Push emerg. shut-off button and go to back to see that solenoid has activated and released the spring loaded flap on the shut-off housing that's on the blower air intake. Do the same with the switch in the engine compartment if you have one. That's what I do periodically to make sure it works.

Hobie · June 27, 2007, 03:46:16 PM

Ok guys, now I'm puzzled. Why would a factory installed turbo not require an emergency shut down while a non turbo has one? I understand that a turbo requires different injectors but why isn't there some other device to shut off a runaway engine?

Heck maybe even a CO2 fire extinguisher with a cockpit switch to blow into the intake?? Would that do it?

Quote from: TomC on June 27, 2007, 08:08:06 AM
Typically when turboing the engine, you remove the emergency shut off. But this also means you're replacing the injectors to the spring loaded turbo injectors. If you have not replaced the injectors, then keep the emergency shut off. Don Fairchild removed my emergency shut off (and you'll notice that factory turbo engines do not have emergency shut downs) and now I'm using the spare wire for my misting system. Good Luck, TomC