i have a 18 h.p. b/s on a lt. its a new motor i bought about a year ago . i bought it from a neighbor that has since moved out of town. it only has about 30 min on it. my son was running it and it locked up. we removed the head on the left side. piston is ok, but the valves are not moving. i have compression on the right side. any one have an idea what may be wrong? i need it running soon. thanks

something happened to the cam if the valves aren't moving.

well i forgot to say its not a vanguard its a flat head i/c engine, i have compression on the other side.

You got me then!! Maybe you cracked a piston????

i found the problem. i removed the engine from the frame. i took the back cover off and parts came falling out. it is a gear that goes on the crankshaft that turns the cam. i am not sure why it did this ? i am on my way to the shop and order the parts.