210 High Cylinder Temps

T

Tom Hale

Filing Flight Plan
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Tom3holer
Hi,
I am new to this forum and have a C-185 but am helping my friend get comfortable in his newly acquired 64 C-210 non turbo
One issue we noticed is the #5, I believe, cylinder temp will shoot past 400-420 on a normal climb and you have to lower the nose for more speed to get it below 400. In cruise with oat's around 30-40F at 24sq we have to keep the cowl flaps open somewhat to keep temps below 380.
The plane just came out of an inspection and FF is slightly past redline on TO and all baffling is in good condition. The previous owner admitted it always seemed to run hot. The readings are from a JPI700. The Cessna head temp gauge also reads high.
Is this a common issue with these birds or is there something we need to look for?
Thanks for any suggestions,
Tom
 
Is his engine an IO-520? Does his FF at takeoff show about 28.5 gph? I'd try to pull the injectors on #5 and clean them. He can look up ultrasonic cleaning or have his shop do it. If that doesn't help any, maybe verify the inner baffles are sealed well and RTV any gaps. Lastly, different CHT probes read slightly differently, figure out which ones he has and see if that has any bearing. (i.e. "Note that the spark plug gasket probes in some engines may run 50 to 100 Fahrenheit degrees hotter than the thermo well" ---from Insight).

Maybe someone else can give more/better information?
 
Kevin,
Thank you for the reply. Yes, it is an IO-520. FF is past the redline on the aircraft ff gauge and I am not sure on the JPI ff gauge. The egt on #5 seems reasonable in the low to mid 1400's as I recall. It does have Gami's. I was just wondering if this is a somewhat common issue with early 210's.
We plan to do a flight in a few days to take some readings.
 
Its common with late 210's also. My '75 T210L runs hotter on #5 also, but not as hot as your friend's. When Im WOT and leaned back, #5 will run close to 380 with about an 80* differential. Cowl flaps closed about 1/2 way.
 
I think troubleshooting may be a dying art. @Tom Hale, try a few things before you break out the wallet. My A&P instructor told me to "always start with the cheapest thing first" when troubleshooting.

1. Check the baffles. They may be worn/cracked/broken/missing.
2. Check the spark plugs. They can tell you a lot about what is going on inside the engine (black = to rich, white = to lean, kinda toast colored is good). And check those gaps while you are in there.
3. Check the physical condition of the CHT probes and the wires.
4. Swap the #5 probe with the probe from another cyl. if the High temp follows the probe, you have a bad probe.

If none of these steps solve the problem, call the local A&P. As for cleaning the injectors - NEVER a bad idea. Clean injectors, clean oil, and clean plugs make for happy (efficient) engines.

One other question; when you shut down the engine by slowly leaning it out, do the RPM's rise just before the engine dies?
 
#5 and 6 should run the coolest. If I had a high CHT on #5 I’d make sure to inspect the oil cooler baffles, inner cylinder baffles, the #5 cylinder shroud, look for an induction leak, and then I’d service the injector.

Doesn’t GAMI size the injectors by mapping EGTs? Diagnosing a clogged injector should be a similar exercise.
 
#5,6 & 2 are the hottest cylinders for that engine (IO-520). There are a few things that can be done to help....but those will be the hottest.

1. make sure the fuel injectors are not clogged. Do an inflight lean to see if the injectors are balanced correctly and all cylinder EGTs peak closely. If not, the injectors either need to be cleaned or changed.
2. overall fuel flow can be increased...many recommend +30 gph vs 28 gph....that will lower all the CHTs.
3. cylinder baffling...make sure it's there and correct. There's an STC for #6 and #2 to improve cooling.
4. the cowl flaps are required....full open or you will see issues with this engine.
 
Stewartb said:
#5 and 6 should run the coolest. If I had a high CHT on #5 I’d make sure to inspect the oil cooler baffles, inner cylinder baffles, the #5 cylinder shroud, look for an induction leak, and then I’d service the injector.

Doesn’t GAMI size the injectors by mapping EGTs? Diagnosing a clogged injector should be a similar exercise.
Click to expand...
you have this backwards....
 
I'd be sure that the injector in number 5 cylinder says #5, just out of annual? yeah.
 
Tom-D said:
Are they not calibrated by cylinder ? and numbered?

Admittedly never maintained any engine with them.
Click to expand...
From what little I've seen they are picked by pairs of cylinders and labeled as such. There isn't much (or any) tuning involved with their standard injector set-ups for each engine type.
 
Tom-D said:
Are they not calibrated by cylinder ? and numbered?

Admittedly never maintained any engine with them.
Click to expand...
They are....but some injectors are the same and others are different. Depends on the cylinder position.
 
Checkout_my_Six said:
They are....but some injectors are the same and others are different. Depends on the cylinder position.
Click to expand...
That is what I thought, you can mix them up and cause the EGTs and CHT to change.
Their website leads me to believe that too.

gamijectors.php
 
Thank you all again for all the suggestions and advice.
We are going to fly in a day or so as the wx here has been lousy the last few days.
I will do all the tests while the owner flys and record the numbers and see where we are.
I think the Gami's are labeled Left and Right with Front Middle and Rear.
Tom
 
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