Low compression low hours 912uls

Right Bill,

I will try again to be sure.

What is the problem?   78/80 is fine!

If you are saying the other cylinders are dead, remeber that you need to put EACH cylinder at TDC while testing.

There are 4 seperate TDCs for 4 cylinders.

I had an engine (800 hours) that had bad rings that burnt oil. Even then it still gave good leak-down compression readings. You could usually hear the compressed air escaping out of the oil tank, i.e. bypassing the rings. Are you sure that there is no air escaping from the inlet manifold or the exhaust on the problem cylinders?

It is relatively easy to remove a cylinder and inspect the rings and at the same time you could look at the valves.