I'm working on a D2 and the pony motor doesn't have any compression. So I pulled the heads off to find an exhaust valve stuck on one side and intake on the other. I turned the piston to top dead center and tapped the valve with a rubber mallet. After freeing them up, now the springs are not pulling the valves closed. I can push them closed with my finger. I am wondering if a retainer might have come off or something but I thought it was quite odd that both sides are doing it. Any input welcome. Thanks,

John

The retainers maybe dropped out when you tapped the valve and the spring didn't immediately extend to keep pressure on the retainers.

Two broken valve springs? Could be. They do break and there's only one on each pony motor valve unlike the main engine valves.

Time to take off the top cover/manifold and have a look!

There isn't a lot of spring pressure in the closed position to begin with. Yours may just be sticking in the guides. There doesn't seem to be any spec for installed height of valve springs although there are specs for testing spring compression. I have shimmed a few using flathead Ford valve spring shims.

Thanks for the help! I went into the top cover and found that I had drove the valve guides in. So the springs where still good. The valves just had to be freed up from the guides. Almost got it back together. The crank sure has a lot of play in it. I guess I will worry about that after I see it run.

Thanks,
John

If the crank has lot's of play then it sounds like the pony main bearings are shot. If that is the case the odd's are good you will break the magneto shaft and/or gear. I am on my second gear and thrid shaft...hoping to get the little beast into the shop soon to make new pony main bearings and change the main flywheel clutch and pressure plate.