Zygrene

Update. The 125k mile F22 came back with 80% leakage on cylinder #2. Readings were taken with pistons at top dead center with the valve cover off. I can hear air that seems to be leaking from the intake valve when I press my ear against the throttle body. Cylinders 1, 3, and 4 are showing 10-13% leakage which I'm told is normal, considering the leakdown was done on a cold engine (it's already out of the donor car). But I'm surprised since compression showed 240 psi on all 4 cylinders a couple months ago and the engine hasn't been run since then.

My question: if I get the head rebuilt and rerun compression/leakdown with solid results, and have the cylinder walls inspected while the head is off, are there any other red flags I should look for or should the motor be good to go?

RolanTHUNDER

80% sounds quite severe! With such good compression readings that is odd. I wonder what the leakdown would be on cylinder 2 if it were warm.

starchland

RolanTHUNDER

Good idea

Zygrene

Yeah the motor is cold... that could be why. Maybe there is some surface rust preventing the valve from sealing properly, since the motor has been sitting a couple months. 240 compression with 80% leak on cylinder 2 doesn't make sense.

riceball777

are you sure you did the leak down test right. Your suppose to put the engine at top dead center and check leak down on cylinder 1. Then turn the engine 1/4 of a turn watch the cam gears so the move 1/4 of a turn then test cylinder 3 do the same thing thing it cylinder 4 and once more for cylinder 2. To be 100% sure you can just do the test with the cams off so you know that all the vales are closed. It this engine was a normal running engine cylinder was not leaking 80%.

Zygrene

Yep. The standard procedure was followed during the leakdown. Best guess, since the engine has been sitting cold for a couple months, is that there might be some surface rust on the intake valve that is preventing a proper seal. My mechanic said he'd try cranking the motor a few times to see if it'll loosen the rust, and run the leakdown again. We'll see soon!