MC8 shutdown

Geoff · February 12, 2018, 05:47:43 AM

We're is the engine safety shutdown control box on an MC8?

Branderson · February 12, 2018, 07:39:26 AM

I probably won't be much help but I have an 8 and the original switch is on the left panel drivers side. Problem is mine doesn't work b/c with the original engine, I'm told that basically chokes the engine by preventing air to get into it. I have a 6v92 which doesn't have that feature so I essentially don't have a shut down button.

luvrbus · February 12, 2018, 07:48:25 AM

Depends Geoff if its a 2 or 3 wire Kysor system they don't use a module,they are wired into the skinner valve all the wiring is on engine rail if you are lucky

Geoff · February 12, 2018, 10:16:04 AM

Yes, I meant the engine shut down to the Skinner valve. Like over temp sends a ground signal to the ? that activates the Skinner valve to send air to the shut off lever on the governor.

gumpy · February 12, 2018, 10:35:17 AM

There's no module. The sensors are wired through some diodes and into the enngine shutdown relay coil ground which breaks current to the skinner valve.

Geoff · February 12, 2018, 11:38:57 AM

Thanks! I ground out all temp sensors on the engine and the shut down doesn't happen. Not good.

gumpy · February 12, 2018, 12:08:24 PM

They were often bypassed by line mechanics who "new better". I would start at the shutdown relay and go from there. Do you have the schematic?

Branderson · February 12, 2018, 12:31:11 PM

My temp shut down sensors don't work either. It was one of the things I was going to get looked at for this year's service.

gumpy · February 12, 2018, 02:12:21 PM

Quote from: Branderson on February 12, 2018, 07:39:26 AM
I probably won't be much help but I have an 8 and the original switch is on the left panel drivers side. Problem is mine doesn't work b/c with the original engine, I'm told that basically chokes the engine by preventing air to get into it. I have a 6v92 which doesn't have that feature so I essentially don't have a shut down button.

FYI, the shutdown switch you are talking about is the Emergency Shutdown Switch, which released the intake flapper on the 8V71 engine. Your bus probably also had the engine safety shutdown system consisting of the overtemp sensors, the low oil pressure sensor, and optionally the low oil level. That system is probably still intact after the engine swap, and would work the same, if still operable. The emergency switch would not, as you've indicated.