The Ford Barn

BUBBAS IGNITION · 06-05-2013, 04:06 PM

Some verbage explainng the operation of the Ford distributor Vacuum brake , a very mis-understood part of the operation...
Part 2 is on the next post ....oops ???

BUBBAS IGNITION · 06-05-2013, 04:11 PM

Page 2 .....

Step-down · 06-05-2013, 09:07 PM

Thanks Bubba ,read it and going to read it again tomorrow ......

Tim Ayers · 06-05-2013, 09:50 PM

Jim:

I can't tell you how much I appreciate all of your contributions to this site. It has helped me out tremdously.

Tim

Seth Swoboda · 06-06-2013, 08:31 AM

Bubba, as the others have said thanks for posting these service bulletins. I always read your threads as they are always helpful. I have a copy of the service bulletins and if a guy has a chance to buy them don't hesitate. They are worth it. Thanks again!

Henry/Kokomo · 06-06-2013, 10:15 AM

Sponsored Links (Register now to hide all advertisements)

As always, You 'da man! Thanks for all the assistance and edification.

Ian NZ · 06-06-2013, 05:47 PM

Are the copys of the service bulletins available anywhere.

Old Henry · 06-06-2013, 06:12 PM

Two questions:

1. Why does the ignition need to be retarded to accelerate? That seems backward to me. It seems that to get the engine speed to advance the timing would need to get more ahead of TDC, not closer to it.

2. If less accelerator and, consequently, more vacuum allow the centrifugal advance mechanism to advance the spark, why is that when I'm cruising along at partial throttle without any ping I then get ping when I mash the gas pedal, thereby reducing the vacuum, lowering the brake, and retarding the spark??

It all seems backward to me.

rotorwrench · 06-06-2013, 07:19 PM

It's not so much about acceleration as it is pulling power. A vehicle accelerating on a flat straightaway doesn't require much retard unless it is at wide open throttle. Accelerating up a hill or pulling a heavy load does require some retard of the ignition. You can feel the difference it makes in a car like an old model A with manually adjustable spark advance when you are climbing a steep hill. It doesn't take much retard to do the job either.

Step-down · 06-06-2013, 08:09 PM

Old Henry you have been able to put my confuession into words . Bubba has my Dissy in his shop as we speak .

06-05-2013, 09:07 PM	#3
Step-down Senior Member Join Date: May 2012 Location: Hat City (Danbury CT) Posts: 647	Re: Vacuum Brake Operation Thanks Bubba ,read it and going to read it again tomorrow ...... __________________ "I can't cry as long as I know the Lord has risen "

06-05-2013, 09:50 PM	#4
Tim Ayers Senior Member Join Date: May 2010 Location: NJ Posts: 6,181	Re: Vacuum Brake Operation Jim: I can't tell you how much I appreciate all of your contributions to this site. It has helped me out tremdously. Tim

06-06-2013, 08:31 AM	#5
Seth Swoboda Senior Member Join Date: May 2010 Location: Southern Illinois Posts: 3,795	Re: Vacuum Brake Operation Bubba, as the others have said thanks for posting these service bulletins. I always read your threads as they are always helpful. I have a copy of the service bulletins and if a guy has a chance to buy them don't hesitate. They are worth it. Thanks again!

06-06-2013, 10:15 AM	#6
Henry/Kokomo Senior Member Join Date: May 2010 Location: Kokomo, Indiana Posts: 1,731	Re: Vacuum Brake Operation Sponsored Links (Register now to hide all advertisements) As always, You 'da man! Thanks for all the assistance and edification. __________________ Henry

06-06-2013, 05:47 PM	#7
Ian NZ Senior Member Join Date: May 2010 Location: Taranaki, New Zealand Posts: 922	Re: Vacuum Brake Operation Are the copys of the service bulletins available anywhere.

06-06-2013, 06:12 PM	#8
Old Henry Senior Member Join Date: Oct 2010 Location: Orem, Utah Posts: 5,762	Re: Vacuum Brake Operation Two questions: 1. Why does the ignition need to be retarded to accelerate? That seems backward to me. It seems that to get the engine speed to advance the timing would need to get more ahead of TDC, not closer to it. 2. If less accelerator and, consequently, more vacuum allow the centrifugal advance mechanism to advance the spark, why is that when I'm cruising along at partial throttle without any ping I then get ping when I mash the gas pedal, thereby reducing the vacuum, lowering the brake, and retarding the spark?? It all seems backward to me. __________________ Prof. Henry (The Roaming Gnome) "It is good to have an end to journey toward; but it is the journey that matters, in the end.” *Ursula K. Le Guin in The Left Hand of Darkness

06-06-2013, 07:19 PM	#9
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,440	Re: Vacuum Brake Operation It's not so much about acceleration as it is pulling power. A vehicle accelerating on a flat straightaway doesn't require much retard unless it is at wide open throttle. Accelerating up a hill or pulling a heavy load does require some retard of the ignition. You can feel the difference it makes in a car like an old model A with manually adjustable spark advance when you are climbing a steep hill. It doesn't take much retard to do the job either.

06-06-2013, 08:09 PM	#10
Step-down Senior Member Join Date: May 2012 Location: Hat City (Danbury CT) Posts: 647	Re: Vacuum Brake Operation Old Henry you have been able to put my confuession into words . Bubba has my Dissy in his shop as we speak . __________________ "I can't cry as long as I know the Lord has risen "