Lapping Valves

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Mad Mart
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Lapping Valves

#1 Post by Mad Mart »

Not necessarily Dolly related but do I need to lap brand new valves into newly cut valve seats?
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xvivalve
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Re: Lapping Valves

#2 Post by xvivalve »

Yes, but they might not need much.
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soe8m
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Re: Lapping Valves

#3 Post by soe8m »

It should not be necessary when your machine shop did cut the seats the same angle as the new valves. When used valves are regrind the best is to lapp because valve grinding is mostly not so accurate.

You can do ofcourse to check you have a 1,5mm contact area and so knowing the seats are cut correctly.

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Magenta Auto Sprint
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Re: Lapping Valves

#4 Post by Magenta Auto Sprint »

The angles would be correct but a light lap as Alun suggested would remove any concentricity issues.

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SprintMWU773V
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Re: Lapping Valves

#5 Post by SprintMWU773V »

In the workshop we give them a light lap in, nothing too much.
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Carledo
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Re: Lapping Valves

#6 Post by Carledo »

I've come across this recommendation with some moderns, notably 16v Vauxhalls and Rovers, where seats are cut and new valves used, but I just don't trust it! Prehistoric mind, I know! Like the others I always give new valves a light lap, so I can SEE that lovely continuous line around valve and seat that says I have a perfect seal.

Steve
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Mad Mart
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Re: Lapping Valves

#7 Post by Mad Mart »

OK, thanks guys. I shall give them a light lap. :thumbsup:
Sprintless for the first time in 35+ years. :boggle2: ... Still Sprintless.

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