Lapping Valves
Posted: Thu Jul 28, 2016 6:14 pm
Not necessarily Dolly related but do I need to lap brand new valves into newly cut valve seats?
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Lapping Valves
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Re: Lapping Valves
Posted: Thu Jul 28, 2016 6:46 pm
Yes, but they might not need much.
Re: Lapping Valves
Posted: Thu Jul 28, 2016 7:03 pm
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.
Jeroen
You can do ofcourse to check you have a 1,5mm contact area and so knowing the seats are cut correctly.
Jeroen
Re: Lapping Valves
Posted: Thu Jul 28, 2016 8:12 pm
The angles would be correct but a light lap as Alun suggested would remove any concentricity issues.
Malcolm
Malcolm
Re: Lapping Valves
Posted: Thu Jul 28, 2016 9:55 pm
In the workshop we give them a light lap in, nothing too much.
Re: Lapping Valves
Posted: Thu Jul 28, 2016 10:46 pm
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
Steve
Re: Lapping Valves
Posted: Thu Jul 28, 2016 11:16 pm
OK, thanks guys. I shall give them a light lap. 