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 12-05-2019, 10:49 AM   #21
mike657894
Senior Member
 
mike657894's Avatar
 
Join Date: Oct 2015
Location: Bay City Michigan
Posts: 1,050
Default Re: Vacuum testing to diagnose fast idle

poor compression should be fixed. burnt or bent valve. maybe get lucky and its a bad head gasket. For worn guides you would need to take out the valves mine bent on the way out so got a new set of old style nos for $30. the valves cant grow. seats can be lapped down. but someone willing to do that amount of lapping will probably correct stem length.
mike657894 is offline   Reply With Quote
Old 12-05-2019, 10:56 PM   #22
Chuck Sea/Tac
Senior Member
 
Chuck Sea/Tac's Avatar
 
Join Date: May 2010
Location: Between Seattle & Tacoma
Posts: 2,351
Default Re: Vacuum testing to diagnose fast idle

When you say loose valve guides, do you mean worn stem clearance, or not securely attached?
Chuck Sea/Tac is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 12-06-2019, 04:01 PM   #23
1931 flamingo
Senior Member
 
1931 flamingo's Avatar
 
Join Date: May 2010
Location: new britain,ct 06052
Posts: 9,389
Default Re: Vacuum testing to diagnose fast idle

I would think worn stem clearance.
Paul in CT
1931 flamingo is offline   Reply With Quote
Old 12-06-2019, 04:05 PM   #24
alexiskai
Senior Member
 
alexiskai's Avatar
 
Join Date: Apr 2018
Location: Mebane NC
Posts: 2,332
Default Re: Vacuum testing to diagnose fast idle

Right, like the guides have worn away over time and now there's lateral movement as the valves go up and down, causing them to not perform as desired.

Edit: Wanted to share this response I got from a local "classic car restoration" shop when I emailed them to ask whether they would take on a Model A valve job:

Quote:
if it’s that old and you do a valve job it normally blows bottom out
So... not gonna use those guys.
alexiskai is offline   Reply With Quote
Old 12-06-2019, 07:11 PM   #25
Y-Blockhead
Senior Member
 
Y-Blockhead's Avatar
 
Join Date: Jul 2011
Location: Redondo Beach, CA
Posts: 5,817
Default Re: Vacuum testing to diagnose fast idle

A stock Model A has ~65psi compression and bringing #2 up to specs is certainly not going to "blow the bottom out". I agree, find someone else...
Y-Blockhead 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 12:00 AM.