blue piston skirts?

anyone ever seen anything like this before? All four pistons have blue skirts. I'm not sure if they were blue going in, or if they somehow became blue during operation, but this is not something I've ever seen!

Bottom side and top side skirts?

Ian, is that fuel residue? Have you tried wiping it off with a solvent soaked rag?

It's on the top and bottom, yes. Almost looks like the whole skirt was blue all the way around and it wore in some spots, and got covered up with brown around the pin holes

Question?

Do you run 100LL and what was the compression level when you removed the jugs?

I haven't ever run this engine. In fact, I believe the last time it ran was 1992.

Blue

tmbg said:

I haven't ever run this engine. In fact, I believe the last time it ran was 1992.

Click to expand...

Lycoming version of blue balls ??

Not commenting on the blue colour, but are you happy with the condition of the top ring land. I have seen that sort of condition on pistons from detonating cylinders.
Some slight scuff marks, but it doesn't look bad.

Suspect

There is a reason I asked the question above and it is, that in looking at this piston and it's condition. I would have to think it has been running for some time with Hi-blow-by. The wear pattern at the top of the piston, inline with the skit 90* to the wrist-pin line and the skit below that angle shows a lot of blow-by and looks as if it were running for some time in that state. The color of the blue on the skirt is the color of the die in 100LL. It would make me guess that the 100LL that blew-by the rings and onto the skirt would dry there and accumulate over the time from when the blow-by started tell this engine was shut down and you found it there. Just me guessing from a picture and no testing. Yours as always, R.E.A. III #80888

Thanks for the ideas guys!

This engine is getting torn down due to cam corrosion, but the blue piston thing was a new one for me, and everyone I've shown it to as well.