Help on finished engine

I have finally finished my first engine, a Stuart S50 built from plans.

Its loose-ish I can turn it by hand and when I attach a drill to the crankshaft it goes great.

But apply the compressed air and it does nowt. In fact the air appears to be exiting directly via the exhaust.

Help!

Its possibly the valve not sitting well on the port face. Assemble the engine but leave the valve chest cover off then turn the engine over by hand and make sure the valve is not being lifted off the face. You may need a few light strokes of a file in the slot the valve nut goes into.

Its also possible you have just got teh timing wrong. Does the air escape all teh time as the flywheel is rotated by hand or only at two points around the full turn?

J

Its all the time although there is some variation.

I suspect that my valve is a tad too long and its letting air under the edge of it and out through the exhaust, I've turned it so the long side is the sliding edge (if that makes sense!) but now its not sitting properly and I don't have the correct tools here to do anything about it.

The pitfalls of having your workshop a mile across town grrrrrrrr