I am truly at my wits end. No noise, no smoke, no oil/water mix, compression 120-130 on all four ice cold cylinders. Blowing air/fuel out the carb, sucking air in the exhaust! Engine is rotating clockwise as viewed from the front. Company we bought the longblock from says ship it back to them!! This is for my 18 year old son who really has his act together to get to work in. Tomorrow we are going to loosen all rockers, verify TDC and try resetting valves but we've run them once already. I simply CANNOT IMAGINE how this is possible!!! Thank anyone in advance for suggestions!!

 

Have you verified the cam and crank line up appropriately? Could the cam be 180* out?

 

If it's not now then something has gone horribly wrong. Forgot to state in the first post that its been running great for around six months... Sorry.

 

Engine bars over by hand normally.