My 73 sIII has been burning a little oil lately. I noticed it when the the truck is warm and idling or when pulling away I get a puff of blue then it clear until the next idle. I decided to conduct a leak down test, and the results are somewhat inconclusive. I started at cylinder 1, rotated the engine until the piston was TDC attached the airline which was set to 100psi pressure dropped to 20psi. The same happen to cylinders 2 and 4, but 3 was solid no pressure drop. With cylinders 1,2 and 4 I could hear an feel the air escaping through the exhaust. So it should indicate exhaust valve issue, right? However the pressure dropped seemed extreme for my blue smoke symptoms. So I retested again got the same results, however..... The cylinders were definitely at TDC but if when the pressure test was engage I rotated the engine ever so slightly the pressure would go back up and I could feel it against the wrench. I then disconnected the air rotated the engine slightly and reattached, gauge would the go up to 100psi then fluctuate and return to original 20psi reading that I was getting.
So I wondering its been 15 years since I last did a LD Test on an engine. Too much pressure? are the tappets are off slightly so that they aren't closed at TDC?
Am I'm on the right lines before I rip off and rebuild the head. thanks.
So I wondering its been 15 years since I last did a LD Test on an engine. Too much pressure? are the tappets are off slightly so that they aren't closed at TDC?
Am I'm on the right lines before I rip off and rebuild the head. thanks.
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