Learning About new to Me C-85-12F

Mooney Fan

Mooney Fan

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Indian Mound, TN
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Mooney Fan
Have 5 hours now with my new to me C-140 with the C-85 w/0-200 crank STC. Has 460 SMOH in 2011 w/ new ECI cylinders kits. Reviewing logs it appears cylinder #2 has repeated issues with going through rings (2 sets) and needing piston blasted and cylinder honing/valve work. Compressions all 70 or better. No metal making going on. Great oil pressure at 50psi. Engine temps on the cool side with no winter kit. Curious as to why one cylinder needs attention more than others. My Lycoming ran hotter on #2 just because.
 
Incorrect or loose baffles can give you grief.

That cylinder may then have localized hot spots that can lead to distortion or

possibly cracking.

If air is not forced between the fins it will not act as a coolant.

One cylinder with a hot spot would likely not show on Oil Temp.
 
Magman said:
Incorrect or loose baffles can give you grief.

That cylinder may then have localized hot spots that can lead to distortion or

possibly cracking.

If air is not forced between the fins it will not act as a coolant.

One cylinder with a hot spot would likely not show on Oil Temp.
Click to expand...

Agree with Magman. I've owned a C85-12F for twenty-five years. It's installed "Cub Style" with open cylinders, but there are little metal plates to help drive the cooling air. For your installation, I'd take a look at a diagram of C-140 baffles and ensure you have every single part included. Here's a picture I found:
upload_2021-1-28_10-32-47.png
Beyond that, of course, it's the normal things...ensuring the baffle seals are good, properly installed, etc.

Ron Wanttaja
 
I don't think you know from that information what the issue was because if you pull a cylinder, for any reason, you're going to have to hone it and put in new rings or you'll never get it to seat in right. Blasting the piston is just a "while you're in there" thing so that's meaningless. Maybe it was a valve issue and something didn't go quite right the first time so they had to do it over. If it's running fine now I wouldn't worry too much about the history.
 
Silvaire said:
I don't think you know from that information what the issue was because if you pull a cylinder, for any reason, you're going to have to hone it and put in new rings or you'll never get it to seat in right. Blasting the piston is just a "while you're in there" thing so that's meaningless. Maybe it was a valve issue and something didn't go quite right the first time so they had to do it over. If it's running fine now I wouldn't worry too much about the history.
Click to expand...
I'd do a good inspection first, the cylinder may be over sized already.

I just did a cylinder that was already .015" over and wore out. That is as far as we can go.

maybe a STC, or chromed back to size.
 
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Silvaire said:
I don't think you know from that information what the issue was because if you pull a cylinder, for any reason, you're going to have to hone it and put in new rings or you'll never get it to seat in right.
Click to expand...
Not always,, the cylinder may be a chromed cylinder, and it may require 3 or more sets of rings to get a set that will seat.
 
Mooney Fan said:
Have 5 hours now with my new to me C-140 with the C-85 w/0-200 crank STC. Has 460 SMOH in 2011 w/ new ECI cylinders kits. Reviewing logs it appears cylinder #2 has repeated issues with going through rings (2 sets) and needing piston blasted and cylinder honing/valve work. Compressions all 70 or better. No metal making going on. Great oil pressure at 50psi. Engine temps on the cool side with no winter kit. Curious as to why one cylinder needs attention more than others. My Lycoming ran hotter on #2 just because.
Click to expand...
The small continentals are terrible about valve sticking and carbon buildup issues. If it’s only one cylinder it may not be getting proper cooling, or may be running richer than the others. It’s only around $100.00 in parts to re-ring and seal a cylinder plus the
Mechanics time if you can’t do it your self or under supervision.
 
Thanks for the input everyone. Engine Is running fine. I’ll be keeping a close eye on it as I get to know the plane better.
 
63AABDFE-8C6B-47E2-806E-97CCD2AF214B.jpeg
Why is it about Mooney’s and 140’s going together? Read my signature.

make sure all the baffling is correct and make sure that the intake tubes and hose connections are correct. Taking my O-200 A apart recently revealed a hose that was not together correctly causing a restriction and a vacuum leak on that cylinder.
 
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