Valve Lapping and Grinding

This seems like a good time of year to ask these questions. What is the proper way to lap valves? When do you need to grind vs. lap them? I've not done a valve job since High School 20+ years ago.

Sorry for the cross posts, but I didn't get any response on the 250F side of the house yet.


I used to manage a m/c cylinder head shop.

I would only use lapping as a witness of the seat you just cut.

If you are to the point of doing this, the head is off and in your hands, I can recommend a few good shops that can do a serdi valve job and recut your valve faces concentric to the stem.

If your head is clean and disassembled it shouldn't be more than 150$ for this.

I don't think lapping is going to give you the results you are looking for.

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