The Ford Barn

lignell · 10-19-2017, 01:04 PM

I was wondering when I shut of my 39 ford but fail to turn of the key will I burn out my points?

ford38v8 · 10-19-2017, 01:17 PM

The key only enables the ignition switch to turn on or off.

flatheadmurre · 10-19-2017, 01:20 PM

The key doesn´t do anything to the electric system...it´s only for anti theft.
It´s the switch that left on will harm your ignition.

rotorwrench · 10-19-2017, 02:23 PM

The chances are likely around 50/50 that the distributor breaker points will be in the closed position when the engine stops. If the flip switch is left on when this happens, the coil will just set there as an electro magnet until either it's fried or the battery is dead or both.

As was mentioned, the key just locks the switch in the off position and arrests the steering movement.

supereal · 10-19-2017, 03:24 PM

The usual result of failing to get the ignition turned off is a cooked coil. That is why a battery disconnect switch is a very good idea. It usually happens if the engine dies when parking. Double checking the switch is a very good habit. I found that out long ago even before my old memory bank started to fail.

lignell · 10-20-2017, 07:10 AM

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thanks for all the information

Hoop · 10-20-2017, 01:23 PM

"The chances are likely around 50/50 that the distributor breaker points will be in the closed position when the engine stops."

Actually quite a bit worse. If the dwell is correctly set at 36, the points will be closed for 36 of 45 degrees for each cylinder firing. That's 36:9.

... or 4 chances out of 5 that the points are going to be closed.

Sorry to nitpick but it's important to know the risk of being careless.

Edit per later post:
"And engine tends to stop on compression strokes and the points are open near there."

A V8 flathead engine is always "on compression" ... it's NEVER without pistons on a compression stroke. Have no idea how this applies to whether the points are open or closed on shut down.

If someone wants to explore this, start and stop your engine a significant number of times and record the position of the points each time.

rotorwrench · 10-20-2017, 03:17 PM

And engine tends to stop on compression strokes and the points are open near there. I don't know if a person could ever really calculate for that kind of chaos.

Murphy's law would be more inclined to guarantee that they would be closed on that day that you forget and leave the switch on.

grumppyoldman · 10-20-2017, 04:06 PM

No!!!

10-19-2017, 01:04 PM	#1
lignell Senior Member Join Date: Oct 2014 Location: capecod Posts: 123	ignition I was wondering when I shut of my 39 ford but fail to turn of the key will I burn out my points?

10-19-2017, 01:17 PM	#2
ford38v8 Senior Member Join Date: Jul 2011 Location: SF Bay Area Posts: 7,634	Re: ignition The key only enables the ignition switch to turn on or off. __________________ Alan

10-19-2017, 01:20 PM	#3
flatheadmurre Senior Member Join Date: Apr 2015 Location: Sweden Posts: 3,045	Re: ignition The key doesn´t do anything to the electric system...it´s only for anti theft. It´s the switch that left on will harm your ignition.

10-19-2017, 02:23 PM	#4
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 18,006	Re: ignition The chances are likely around 50/50 that the distributor breaker points will be in the closed position when the engine stops. If the flip switch is left on when this happens, the coil will just set there as an electro magnet until either it's fried or the battery is dead or both. As was mentioned, the key just locks the switch in the off position and arrests the steering movement.

10-19-2017, 03:24 PM	#5
supereal Senior Member Join Date: Jul 2014 Location: Iowa Posts: 1,634	Re: ignition The usual result of failing to get the ignition turned off is a cooked coil. That is why a battery disconnect switch is a very good idea. It usually happens if the engine dies when parking. Double checking the switch is a very good habit. I found that out long ago even before my old memory bank started to fail.

10-20-2017, 07:10 AM	#6
lignell Senior Member Join Date: Oct 2014 Location: capecod Posts: 123	Re: ignition Sponsored Links (Register now to hide all advertisements) thanks for all the information

10-20-2017, 01:23 PM	#7
Hoop Senior Member Join Date: May 2010 Location: Jacksonville FL Posts: 1,137	Re: ignition "The chances are likely around 50/50 that the distributor breaker points will be in the closed position when the engine stops." Actually quite a bit worse. If the dwell is correctly set at 36, the points will be closed for 36 of 45 degrees for each cylinder firing. That's 36:9. ... or 4 chances out of 5 that the points are going to be closed. Sorry to nitpick but it's important to know the risk of being careless. Edit per later post: "And engine tends to stop on compression strokes and the points are open near there." A V8 flathead engine is always "on compression" ... it's NEVER without pistons on a compression stroke. Have no idea how this applies to whether the points are open or closed on shut down. If someone wants to explore this, start and stop your engine a significant number of times and record the position of the points each time. __________________ "Remember that when it comes to intelligence, half of all of us are below average." Last edited by Hoop; 10-22-2017 at 07:04 AM.

10-20-2017, 03:17 PM	#8
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 18,006	Re: ignition And engine tends to stop on compression strokes and the points are open near there. I don't know if a person could ever really calculate for that kind of chaos. Murphy's law would be more inclined to guarantee that they would be closed on that day that you forget and leave the switch on.

10-20-2017, 04:06 PM	#9
grumppyoldman Senior Member Join Date: Apr 2017 Location: Texas Gulf Coast Posts: 727	Re: ignition No!!!