I had 185 in cylinders 1,2,3 but 4 had 90. With a wet test, the 4th cylinder compression went up to like 120.

I now have the head off. All the pistons and sleeves look good. Not a scratch on there, heck, I can still see the cross hatch marks.

Anyways, I see oil on ONLY the 4th cylinder valves. Piston ring?

 

Do a cylinder leakage test...then take off the oil fill cap or take out the dipstick...too bad you already have the head off