03-20-2019, 10:25 AM | #1 |
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Join Date: May 2010
Location: Lynden, Wa
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Valve lapping
OK, I searched but could not find an answer to my questions. I am beginning to lap the valves and am using some lapping compound that the machine shop gave me-Permatex. So I started on #1 ex as a test. I have a ZIM hand crank lapper but it would not even budge the valve-even after I put oil on the stem and worked it around by hand. So, I used the long stem and did it by hand-worked decently (I just bought the wood stick version). The guides and springs are in aaand so are the keepers-my knuckle head exuberance. So I will take them out one by one and lap them. My questions are:
1) I know I am looking for a thin stripe around the middle of the valve that is nice and shiny. But after a few rotations I looked and it look really rough with the shiny parts at the top and bottom of the valve. I assume this will go away as they seat together? 2) How long should this take per valve? I don't want to just keep going and ruin a valve and seat. 3) Best way to get the compound off the seat and valve? Thanks, Mike
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03-20-2019, 10:47 AM | #2 |
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Location: Portland OR
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Re: Valve lapping
New valves and fresh cut seats? Three face seat or single? Any time I have lapped valves, I see a gray ring around the sealing edge, not shiny. Does not take long, just looking for no missed spots on valve or seat. I clean up with mineral spirits. I rub the valve laper between my hands, lift/turn some and repeat. If your seats are 3 face you really do not need to lap, the rotation of the valve will seat itself. (So I have been told )
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03-20-2019, 11:11 AM | #3 |
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Re: Valve lapping
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03-20-2019, 12:34 PM | #4 |
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Re: Valve lapping
Before lapping I would suggest checking the face to seat contact with pencil. 3 or 4 strokes with the pencil across the valve face then rotate a bit in the seat and look at the contact. It should be slightly toward the stem from the center of the face and .060-.080" wide for intakes and .080-.090" wide for exhaust. If they are not correct then a seat grinder/cutter is used to change the contact point and width. Once the contact points are correct then a slight lapping can be done, but, its not needed.
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03-20-2019, 01:02 PM | #5 | |
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Re: Valve lapping
Quote:
...................................don't do this !...................................... |
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03-20-2019, 01:06 PM | #6 |
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Re: Valve lapping
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Mike
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1930 TownSedan (Briggs) 1957 Country Sedan |
03-20-2019, 02:14 PM | #7 | |
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Re: Valve lapping
Quote:
Bill W.
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03-20-2019, 06:03 PM | #8 |
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Re: Valve lapping
You did well to last that long! He says this was done by a profesional. Profesional what?
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