In The Hanger with Jim Jones - Lapping an exhaust valve in place.

Jim demonstrates his technique for lapping an exhaust valve in a 145 HP Warner radial engine, without removing the "jug" from the engine.
Our first attempt. Not the best audio. Shot in the hangar with 40 knot gusts and occasional rain. Things will get better.

[@sophistical]

Great video! How did you clean out the grinding compound? Vacuum? Solvent?