03-30-2022, 04:30 PM | #1 |
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Posts: 84
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Valve Guides
How much movement should a valve have in a valve guide? It appears that there is some gap causing the valve to rock back and forth. So how would you tell if it is time to change? it is very little but there is movement. I have had a lot of blow by. Thinking of up grading to later valves and adj lifters.
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03-30-2022, 05:03 PM | #2 |
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Re: Valve Guides
I don't recall seeing any specs specific to a Model A engine, but 0.001-0.003 would be acceptable, with the larger tolerance for the Exhaust valves. More important would be how the valves are seating.
A lot of blow by would typically be attributed to rings. A leakdown test would help you to determine what's happening. |
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03-31-2022, 09:18 AM | #3 |
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Re: Valve Guides
A rule of thumb is that intake valves need a guide-to-stem clearance of .001″ to .003,″ and exhaust valves need from .002″ to .004″ guide-to-stem clearance.
Measure the guide ID's with the guides installed using a ball gage. Measure the valve stems with a micrometer of vernier caliper. I would question any check that specifies an amount of valve wiggle because the amount of wiggle is a function of the valve guide's length plus the stem-to-guide clearance.
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Bob Bidonde |
04-01-2022, 09:45 AM | #4 |
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Re: Valve Guides
Caution:
(The following is intended to be humorous) I once had an old Dutch mechanic tell me the clearence should be; "loose mit no slop" Sort of a "mechanics tight" type of measurement! Brian W. |
04-02-2022, 06:03 AM | #5 |
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Re: Valve Guides
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04-02-2022, 08:09 AM | #6 |
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Re: Valve Guides
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