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Discussion in 'Maintenance Bay' started by Tom-D, Nov 21, 2017.
See anything wrong with the cylinder in the picture?
Pic one shows left valve closed, right valve stuck open, yet pic 2 shows both valves closed?
Second picture was after I heated the cylinder and allowed the valve to close to get the springs off. nothing particular about the burn pattern? absolutely no carbon in the middle of the combustion chamber.
tough to tell from the pics but the valve on the right looks torched from about 1 to 4 o'clock.
Is this an optical illusion from pic2; looks like the grand canyon!
The valve guide was carbon-ed up bad enough I had to drive the valve out with a 2 pound sledge.
That messed up the guide so bad I threw the cylinder away, the bore wasn't that good either.
I have better cylinders to rebuild than this one.
In photos #1 and #3, is that a crack at the spark plug boss ?
no. just a camera glitch.
no just black carbon from burning auto.
Do ya still need us to tell ya what to do wit dat?
That cylinder is already thrown away what else would ya do with it?
Make another lamp.
call the FSDO....for coffee?
So, caboned up. Due to using Mogas or just too rich?
It is my belief that the use of auto fuel allowed very hard carbon to build up on the valve stem. This made it impossible to remove the valve. I've seen it before but not this bad.
Cylinders this bad aren't worth trying to fix, simply because of the cost of parts.
When I overhaul an engine that had cylinders replaced I save the good ones for occasions like this. It's a shame to throw away 50 hour new cylinders when the customer wants all new, and many don't want their old cylinders back.
see anything wrong? its not a lycoming?
Doesn't work like that.. ya got to have a badge to get near their coffee mess.
This seems to be one of those chicken or the egg syndromes. I wouldn't expect a valve guide with the proper clearance would allow enough carbon to build up to cause a sticky valve. So what happened first? Carbon buildup or valve guide wear that left enough space for the carbon to build up?
What was the last fuel that got run through the engine? Unleaded or leaded? I had a valve stick on me in a Continental powered airplane that I fueled with 100LL after it had run hundreds of trouble free hours on unleaded car gas. It may have just been coincidental but I think the fuel was a contributing factor.
Same thing here prior owner ran auto, this owner runs 100LL, some where over 100 hours by this owner.
Wish I'd saved the valve. Hard diamond like carbon on one side of the stem, badly worn on the other, guide visibly out of round.