lapping valves

[Jim Wilkinson]

I am replacing a head gasket. Should I lap the valves etc. if the tractor (wd-45) didn't smoke before I tore the head down?

 

[Bob Huntress]

If you did not remove the valves from the head, I wouldn't automatically lap them simply changed the head gasket, yet, if you removed the valves from the head, I would at least clean the surfaces and blue them. If they don't blue true, I would lap them.

 

[Dick L]

Lapping valves is not a substitute to grinding valves. Lapping is to enhance the seats after grinding and refacing.