CHT for an early Citabria

R

rackley

New member
Hello All,

I have a 1969 7GCAA with a low time engine that seems to run fine. My cylinder head temp seems high to me when climbing at full throttle. The some what accurate CHT gauge reads 430-450 with the oil temp usually below 175. After leveling off and a power reduction the CHT goes to 350-375. Everything feels and performs normally but that CHT number in the climb scares me. I have new baffling but I question the airflow exiting the cowling. So my questions for the experts on this page are ........what is normal and is this a problem for older CItabrias?

Thanks,

Rich Ackley
 
You don't have an email address posted- I would send you the link. Google "Lycoming o-320 operating manual". It addresses cht in cruise..but not in climb unless I overlooked it. I fly a 1965 GCAA with the O320.
 
http://aeroclub-lehavre.e-monsite.com/medias/files/pa28-lycoming-o-320-operator-s-manual.pdf

Link to the O320 manual
 
In a hard climb in socal on a 100°F day, I can barely get my CHT's to hit 400. 1970 7GCBC, O-320-A2B 2400TTSN. The Oil temp would be my limiting factor in my airplane. What kind of probe are you using? The manual will reference probes in the probe wells in the bottom of the cylinder. Spark plug gasket probes on the bottom plug will read 20-40°f hotter.
 
Thanks for the information. My CHT probe is the spark plug type that is on the bottom plug of the left rear cylinder. I guess I could move it to the top or even a different cylinder for a lower reading, but that is not correcting a problem if I truly have one.

Thanks,

Rich
 
Bottom left rear is #4, which is usually second hottest (#3 is typically the hottest on carb'd lycomings). But the specs in the manual is assuming the well type bayonet CHT gauge, not the spark plug type. I assume from the numbers that it's a digital readout? If it's a JPI or EI gauge, consider buying the Bayonet style probe, and putting it in #3 cylinder, or if you can bear the expense, going to a bar graph. I have a UBG-16 in mine, but I find that kind of engine information invaluable because I'm a engine geek... and for a long time I was playing the TBO-busting game.
 
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