skinny z wrote:Somewhere in a not to recent post there was a discussion about lapping valves. More of a check to see if the old valve job was still holding up
If all you're trying to do is create a 'witness' then use something fine, at least 800 grit
You'll get the usual opinions about 'lapping', as if it's all one and the same thing which it's not, as you understand ..... as long as you're not trying to 'correct' any machining with it you won't go far wrong
I'm sad enough to make my own ..... never found a shop bought product that even came close to being usable without doping it in some way ...... IIRC the average particle size is around 0.0005"
So even if you had the inclination, you're not lapping anything 'in' in the accepted sense any time soon, and I've never had an issue with clean up