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Re: Exhaust Valves and Exhaust Risers

Posted: Mon Apr 01, 2019 1:08 pm
by blsewardjr
My DA40 Lycoming IO360 #1 cylinder had a static compression of 45/80 this past annual. Based on Mike Busch's advice above I was reluctant to pull the cylinder. Instead, my mechanic "lapped" the valve and was able to get the compression up to 63/80 cold. We're going to re-check after 25 hours.

Re: Exhaust Valves and Exhaust Risers

Posted: Tue Apr 02, 2019 2:00 am
by RMarkSampson
Found this article from Mike Busch, published nearly a decade ago. Still very relevant. Apparently there is a part two to this article that discusses borescopes but I have not been able to google it. However, more recently, Mike Busch published an article in AOPA that discusses borescopes. Since you mentioned "rechecking at 25 hours" - when you pull that spark plug out for a compression check, sticking in a borescope is time well-spent.

https://www.aopa.org/news-and-media/all ... -borescope