Lapping in valves
Lapping valves yourself is pretty hard-core. I have always been amazed how cheap it is to get heads rebuilt at a shop, even w/ hardened seats installed (consider that if you don't have, to run unleaded gas). My understanding is that shops no longer lap valves, they just rely on the accuracy of the grinding machines.
I have read this bit of info on-line in several places, worth considering I guess so I will post it here............
valve lapping is out of date. lapping is for old engines before hard seats were introduced. all of the B&S valves and seats are hardened and lapping will only slightly polish them. not worth the time.................
it has been shown that once an engine reaches operating temperature, the valve and the seat - being different materials and surrounded by different masses - have expanded at different rates, so the lapped areas on the valve and the seat do not contact each other in the same areas as when they are cold.
Lapping valves is a waste of time.......................
Still going to lap my valves but I will continue to look into this, not sure where Im going to find any sort of definitive answer but maybe something will come to mind. Somehow I believe calling any local machine shop will just yield more opinions instead of scientifically proven facts.
I will be calling Clover Monday, they carry a full line of lapping compounds, while I am sure they will be biased as far as the performance of lapping compounds I also believe they will have a bit more experience with these things than I do.
In the meantime I am still going to play with whats avail over the counter too me.
