Although I'll do either one the owner wants, I prefer the automotive style
tester. I can hear wheezes and such using this method that the other test just
will not show. Whistle through the carb, you've got an intake valve leak.
Singing out the exhaust, exhaust valve. Blowing out the crank vent and it is
blowby the rings. Lots of good information.

AND you don't have to get in the arc of the propeller and hold it steady against
80 pounds of pressure...you KNOW the propeller is going to spin.

Jim

P.S. It is not necessary to put the same question in all the rec.aviation.*
newsgroups. Most of us read them all and it is just a waste of bandwidth. This
one probably belongs in ra.owning.


(Doug)
shared these priceless pearls of wisdom:

-Does anyone do an "automotive" type compression test on their aircraft
-engine? I think this kind of "dynamic" test might show problems (such
-as valves not opening all the way), that a leakdown test would not
-(and vice-versa). Anyway my annual is coming up and I want to do it. I
-imagine something that screws in and has a long hose to the guage, so
-no one has to stand behind the propellor.

Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com