A compression test traced the cause of the cyl. 2 misfire on my 98 Outback EJ25 to bad compression in that cylinder - it read 25lbs vs. 155lbs for cyl. 4. Since I cannot see or smell any oil burning, is it reasonable to conclude that the problem is therefore valve-related rather than bad rings?It will be a lot easier for me to re-do the head than to rebuild the entire engine, so perhaps this is just wishful thinking.Your informed, serious comments are much appreciated.

Bad Valves or Rings?

May 08, 2007 2 Replies

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BobN 19 years ago

A compression test traced the cause of the cyl. 2 misfire on my 98 Outback EJ25 to bad compression in that cylinder - it read 25lbs vs. 155lbs for cyl.

Since I cannot see or smell any oil burning, is it reasonable to conclude that the problem is therefore valve-related rather than bad rings?

It will be a lot easier for me to re-do the head than to rebuild the entire engine, so perhaps this is just wishful thinking.

Your informed, serious comments are much appreciated.

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Bob's Backfire Burrito 19 years ago

You need to do a "Leak Down" test. When you have pressure on the suspected cylinder, listen by the oil filler, exhaust pipe and intake for flowing air. Could be a burned exhaust valve...could be broken rings.....

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johninKY 19 years ago

Other possibilities are valves adjusted too tight and a leaking HG. HG don't always leak between cylinders. But if I were a betting man, my money is on a burnt exhaust valve.

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