A friend is in the process of buying a cessna 140 and he showed me this picture. He will be having a pre-purchase done on the plane next week but I was just curious about what I was seeing here. He said that 3 cylinders have been changed and one re-built...don't know which ones are which though.
Is this pink (burnt paint) on the rear cylinder normal or is it an indication that things have been over heated?

Looks like it got hot to me or has one hell of a exhaust leak. Also these cont cylinders will crack down between the gap that separates the intake and exhaust ports. I would take a good look at that jug. Also look at how the baffle seals are, that could indicate why the others have had to be done.

Dave

It might posibly be orange paint that has faded with heat. Chromed cylinders are painted thus to identified them.

Yeah, but they don't paint the WHOLE cylinder...

MTV

we had that same thing happin on a cub with a 320 it had about 500 hours on it the cilender went flat when it was cold but tested perfect when warm, when they pulled the jug it was that colour and even brighter orange inside the port. they reamed the guide and got a hard varnishy looking substance out of it. never did come up with an explanation though.

Might have just been painted with non heat resistant paint. A borescope and comp. check will tell the tale. No, I've never seen anything like that. Hard to believe one could get that hot and not seize if it is engine paint.

That cylinder is toast. Pink=mucho heat.

It's not super clear on the attached picture but when I zoom in on the picture on the computer the color changes from the pink to the grey paint right at the spark plug...it looks like there is also some grey paint right near the valve cover. This reminds me of the color of my turbo and some automotive exhaust manifolds I've seen...and we all know those get a bit warm.

It got that hot and didn't seize or even melt the plastic spiral wrap on the ign. leads? Naw, sumpthin else is going on here. Don't have a clue as to what though. I mean how could you even get ONE cylinder that hot anyway? I would think if you got Cyl's that hot from lack of air, you'd cook the case and oil etc. from conduction. Pop the valve cover, if it got so hot it burt the paint pink then it has to be full of coked oil.

What did the pink turn out to be?