Valve Lapping Tip

[ricky racer]

I'm working on a Cub engine swap and I'm going through the donor engine to bring it up to snuff. The valves in general looked pretty good but I've owned the donor engine for a few years and hard telling how many years it's been since it last ran. Anyway, all the valves needed was a good lapping in to assure they seat properly. I used a hand lapping tool, you know the wooden stick with the suction cups on the ends. I was having a hard time getting the suction cups to adequately "grip" the valves to allow me to lap them in. After some frustration I stuck a little piece of double sided tape to the top of each of the valves and the problem was solved. It gripped the valve so good that I could run the lapping tool with my cordless drill motor greatly reducing the time and effort involved. So there you go, the tip of the day!

[Bob McCarty]

Great idea!

[Stanton]

[BigBill]

Did you grind the valves and the valve seats first before lapping them?

[Gary Dotson]

That's a good tip, Ricky, My method has been to spray the top of the valve with a bit of hi-tack gasket sealer. Do what works for you!