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- Oct 11, 2016
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@rodm1 Lapping is used only to achieve the last bits of precision and surface finish. Th OP has to remove between .8 and 1.5 thousandths in a surface many times the size of all the valve seats in a V8 engine. It *could* be done that way, but take many times longer than starting with a die stone set.
We are talking about expedient methods that can be done by a first-timer, without setting up something elaborate. I could try to suggest how to construct usable lap under the circumstances, and try to convey how to use ti without dishing the taper, but doing such a large surface is a little harder than using a commercial valve seat lap. Even for the last stage, polishing I wouldnt use lapping compound of any kind - it is a lot more difficult than using lapping film on a ground backer.
We are talking about expedient methods that can be done by a first-timer, without setting up something elaborate. I could try to suggest how to construct usable lap under the circumstances, and try to convey how to use ti without dishing the taper, but doing such a large surface is a little harder than using a commercial valve seat lap. Even for the last stage, polishing I wouldnt use lapping compound of any kind - it is a lot more difficult than using lapping film on a ground backer.