I'm getting ready to reassemble my Challenger's engine that's been re-honed and getting new rings & new bearings, etc. The piston skirts were a little scuffed up upon tear-down, but cleaned up nicely using a fine-grade Scotcbrite pad. Would there be any benefit to applying a spray-on dry graphite lubricant to the piston skirts as a break-in coating? Or would that be "stuff" that could potentially interfere w/ the rings seating properly as it wears off?

Brad I'm not really qualified to answer your ?. I don't build motors professionally. But I have done this in the past. Used it on the pistons and the crank. That motor sealed up better than any I had up to that point. That was probably 15-20 years ago. Before the more common use of coatings. Your oil will get real dark after breakin. Jim

Thanks for the reply. I'm wondering if this approach would actually be of any benefit vs. spending about $200 to have Swain Tech put on their PC-9 skirt coating. Since this is a rebuild that's going on while I'm still collecting parts for a fresh replacement to use in the future, I'm questioning whether it's worth putting even more $$$ into the rebuild, any real benefit to applying the dry graphite to the skirts myself as a sacraficial break-in coating, etc.

Considering that dry graphite is corrosive to aluminum parts – It would not be my first choice….. Just assemble the engine with the usual care and you should not have issues.

Graphite "lubricant" in a spray can is definately not something to be used in an engine in my opinion.
That would be about the equivelant of pouring fine sand in an engine.
Nothing at all like a coating. Graphite lubricant has a lot of fine paricles in it,which is most likely why oil would turn black after break in.
Keith

That's why I'm asking! I know the aftermarket skirt coatings are generally a graphite and/or moly matrix (w/ a resin component for adhesion?), but wasn't sure if that was anything at all similar to a spray-on graphite product that leaves a dry coating on the treated surface. If the latter is just going to rub off and put a bunch of "stuff" into the oil that's going to mess w/ things, I'll pass.

Too bad I don't have enough time or $$$ to try all this stuff out for myself and learn the hard way.

Well I guess I should clarify, what I used was an aersol Moly dri-film lubricant.

I sent this question in years ago to Mopar Action, and it was printed in the tech!
If you can dig that up. it had a whole article on rattle can piston coatings.
Reason I asked back then, he had done a cheap build up years before, and I was asking about the manufacturer of that aerosol coating.
I will see if I can dig that mag out.
Later
Bob

If you consider that several piston companies supply their pistons coated what does that say?
Next time you see a fueler or pro/stock motor tore down look closely at the pistons.. they're coated.
I've been coating my own pistons for over 10 years with zero problems but it's not out of a spray bomb.

http://www.techlinecoatings.com/hi-performance/index.html

As far as graphite.. years ago that's what was used to break-in camshafts. I still use graphite grease and haven't suffered any failures..

Someone once said.."different strokes for diff..folks"