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Old 12-05-2019, 10:49 AM   #21
mike657894
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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.
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Old 12-05-2019, 10:56 PM   #22
Chuck Sea/Tac
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Default Re: Vacuum testing to diagnose fast idle

When you say loose valve guides, do you mean worn stem clearance, or not securely attached?
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Old 12-06-2019, 04:01 PM   #23
1931 flamingo
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Default Re: Vacuum testing to diagnose fast idle

I would think worn stem clearance.
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Old 12-06-2019, 04:05 PM   #24
alexiskai
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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.
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Old 12-06-2019, 07:11 PM   #25
Y-Blockhead
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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...
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