Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 10-04-2020, 04:22 PM   #1
keyswitch1
Senior Member
 
Join Date: Mar 2019
Posts: 118
Default spark plug gap

What gap should they be set at ?? Thank you !!
keyswitch1 is offline   Reply With Quote
Old 10-04-2020, 04:43 PM   #2
Jim/GA
Senior Member
 
Jim/GA's Avatar
 
Join Date: May 2010
Location: Young Harris, GA
Posts: 1,612
Default Re: spark plug gap

0.035"

.
__________________
Jim Cannon
"Have a Model A day!"
  • Repair
  • Restore
  • Drive
  • Enjoy!
  • Join MAFCA
http://tinyurl.com/Join-MAFCA
Jim/GA is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 10-04-2020, 04:56 PM   #3
keyswitch1
Senior Member
 
Join Date: Mar 2019
Posts: 118
Default Re: spark plug gap

Thank you JIM !!
keyswitch1 is offline   Reply With Quote
Old 10-04-2020, 10:17 PM   #4
700rpm
Senior Member
 
700rpm's Avatar
 
Join Date: May 2010
Location: Portland, Oregon
Posts: 5,341
Default Re: spark plug gap

Quote:
Originally Posted by Jim/GA View Post
0.035"

.
Jim, I respect you as one of the most knowledgeable guys in the hobby, but I would like to offer an alternative to your recommendation based on personal experience.

It is true that the Service Bulletins settled on .035 in Feb 1931, and that has been the accepted standard for 90 years. But as a counterpoint, I’ve worked on and played with these cars since 1961, and my first engine rebuild was done by Lou Hanel about 1965. Lou was a pioneer and a legend in NW Model A engine rebuilding, whose experience went back to about 1940. If you had a Lou Hanel engine, it was known as the best you could get.

Lou has been gone now for about 25 years, but I still have his instructions for engine breakin, in which he says plugs should be gapped at .032. I have set mine mostly to his specs Since 1961, and that has served me well, owning about twenty Model A’s over that period, and driving well over 50,000 miles total in restored and unrestored cars. I have used both .032 and 035 gaps in my plugs, which currently are Champion 3X, but I haven’t noticed a significant difference either way.

So I am not trying to contradict you or the Ford Service Bulletins. I’m just sharing my experience, for what it’s worth. Next time I set my plugs, I’ll try .035.
__________________
Ray Horton, Portland, OR


As you go through life, keep your eye on the donut, not the hole.

Last edited by 700rpm; 10-04-2020 at 10:49 PM.
700rpm is offline   Reply With Quote
Old 10-05-2020, 01:31 AM   #5
1930-Pickup
Senior Member
 
Join Date: Mar 2017
Location: southern California
Posts: 725
Default Re: spark plug gap

Quote:
Originally Posted by keyswitch1 View Post
What gap should they be set at ?? Thank you !!
People are recommending a stock gap size for you, and that's good.

If you have a stock ignition system and engine, then that spec is fine.
The system is also forgiving in that if you change the gap slightly, nothing bad will happen.

Its also true that many folks on this forum run their gaps larger, .040 or .045 maybe. These folks may have a stronger coil compared to the weaker Ford coil, or other modifications that result in a stronger spark.

The point is, when you ask what your gap size should be, its also important to state what type of ignition system you have. Ford parts vs repop vs high performance, fairly new vs 90 years old, 6v vs 12v, electronic vs mechanical, and so on.

There is no doubt that you will get several different answers because folks have had plenty of varying experience working on these cars.
__________________
"That's my wild unsubstantiated guess, and I'm sticking to it regardless of the facts!"
1930-Pickup is offline   Reply With Quote
Old 10-05-2020, 10:19 AM   #6
duke36
Senior Member
 
Join Date: Jun 2015
Posts: 1,228
Default Re: spark plug gap

Sponsored Links (Register now to hide all advertisements)
See other Ford Barn threads : some like .030-.032 for higher compression heads
duke36 is offline   Reply With Quote
Old 10-05-2020, 11:05 AM   #7
Purdy Swoft
Senior Member
 
Purdy Swoft's Avatar
 
Join Date: May 2010
Location: Alabama
Posts: 8,077
Default Re: spark plug gap

Henry was first afraid that the 4.6 compression ratio of the model B engine would blow out the spark .
Purdy Swoft is offline   Reply With Quote
Old 10-05-2020, 11:06 AM   #8
700rpm
Senior Member
 
700rpm's Avatar
 
Join Date: May 2010
Location: Portland, Oregon
Posts: 5,341
Default Re: spark plug gap

1930-Pichup and duke36 are right, of course. I have always run my cars strictly stock, which reflects my comment above.

Hey Purdy! How are things in Alabam?
__________________
Ray Horton, Portland, OR


As you go through life, keep your eye on the donut, not the hole.
700rpm is offline   Reply With Quote
Old 10-05-2020, 11:35 AM   #9
Purdy Swoft
Senior Member
 
Purdy Swoft's Avatar
 
Join Date: May 2010
Location: Alabama
Posts: 8,077
Default Re: spark plug gap

It has cooled off a bit here .
Purdy Swoft is offline   Reply With Quote
Old 10-05-2020, 11:43 AM   #10
Purdy Swoft
Senior Member
 
Purdy Swoft's Avatar
 
Join Date: May 2010
Location: Alabama
Posts: 8,077
Default Re: spark plug gap

I run higher compression heads on some of mine . I run and have good results with a spark plug gap of thirty five thousands on all of them .
Purdy Swoft is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 08:23 PM.