Acro Image

Aerobatics Server

ACRO E-mail Archive Thread: [Acro] S-2B engine temps?

[International Aerobatic Club] [Communications] [Aerobatics Images]

Disclaimer: These aerobatics pages are developed by individual IAC members and do not represent official IAC policy or opinion.

[Usage Statistics]

ACRO E-mail Archive Thread: [Acro] S-2B engine temps?


Thread: [Acro] S-2B engine temps?

Message: [Acro] S-2B engine temps?

Follow-Up To: ACRO Email list (for List Members only)

From: DSowder at

Date: Mon, 23 Sep 2002 05:24:54 UTC


  Is anyone else flying an S-2B with a 6-cylinder engine analyzer? I put a JPI 
EDM-700 analyzer on my B at the same time the engine was rebuilt, and have 
put 420 hours on it since. The No. 1 cylinder always has the coldest EGT and 
CHT, no matter what the power setting or how I lean. EGT is about 60 to 90 
deg. colder than #4 (usually the hottest), and CHT is about 30 or 40 deg. 
colder. This despite swapping injector nozzles, EGT and CHT sensors. The No. 
1 cylinder seems to peak at about the same mixture setting as the other 
cylinders, it's just always colder.

For some reason this is bothering me more these days. It would seem that the 
only answer is that #1 is getting less air for some reason, but it seems that 
would make it run richer and thus peak much later (i.e. with the mixture 
control pulled further out). It's run this way since "sort of new"; I never 
flew the airplane before this engine rebuild. The engine is strong and 
smooth, and compression is excellent. Just curious to know if anyone else 
sees a similar temperature spread.

Doug Sowder


© Dr. Günther Eichhorn
Email Guenther Eichhorn