The air valve in the superior engine we are rebuilding is a hurting unit. It has what looks like a thick rubber washer on the rod and is all cracked and torn and extremely hard. It looks like it was made by someone with a dull axe. The parts page I have shows items 43 - rubber washer, 43-B - fibre washer, and 44 - plate for air valve. Do any of you experts have first hand knowledge working on one of these valves that could offer any advice on making these parts. the metal plate looks in good usable condition. I was wondering if a piece of heavy rubber conveyor belting would be ok to use as the rubber disk? The ugly piece that was in there seemed to be cup shaped. It also had nails through it and through small holes in the metal plate and bent over. I appears it was complete fabricobbled unit.