2 1/16" -- 52.4mm piston options for a Mac PM8200

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The little bit I am seeing of that piston would not stop me from sanding down the high spots and putting new rings for a runner. Now if going for a collector piece Eli know that wouldn't fly but what you got to lose?
 
Thanks for all the great input, fellas. I think what I need for the circlip removal getting a pic under the end of one is a third hand. But I'm also concerned about gouging the clip seat or buggering up the clip continuing down that road. The main issue with the clips is to get at least one removed without deforming it since I doubt they are any more available than the piston and I'll probably need to re-use it unless a new 12mm clip will be a suitable replacement. The coating idea is intriguing and may be the final option depending on how successful I am with a very careful restoration attempt..., once I get the piston off the rod, of course. After going at it with the pic approach and only drawing blood I'm now inclined to grind a notch into the pin boss for the more typical method of access to the clips. I'll do both sides for symmetry and will certainly have an easier time if I need to pull the piston again. And yep, the ol' baggie trick had already entered my mind. I have some 20 micron lapping paper on the way to work the high spots and will give Berrymen's Dip a try for loosening up what I'm convinced is sealant impregnated onto the piston from a seriously sloppy assembly of the short block and what is largely responsible for some of the abrasion. Also looks like something else was ingested or got loose to cause some additional scrapes and pitting. As for the cylinder, there's no aluminum transfer except what appears to be a very small area almost at the squish band..., which is a pretty odd place for it if that's what it actually is. Otherwise it's nice and smooth and only shows the streaking associated with the wear marks on the piston. Will clean up like new with a little work.

Again, I appreciate everyone's input. I'll post updates as they occur.
 
Got the piston off. Notched it to pop the clips but had to really heat up the pin bosses to get the wrist pin out and had to use my arbor press ta boot. It was obviously press fit along with the clips. A few pics. Notice the pieces of whatever in the case. There's also a weird piece in the retaining groove for the large bearing that I'm assuming is a guide or stop that corresponds with the gap in the bearing snap ring? Was going to soak the piston in Berryman's Chem Dip but they advise the possibility of adverse results with certain aluminum and aluminum alloy parts after prolonged exposure which was the plan..., an overnight soak to de-carbon and de-gunk before trying any smoothing. Swaintech is looking better and better as an option.

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PogoInTheWoods said:
Not a problem, Ron. And I appreciate you keeping an eye out. You don't know how many times I've hit that link wishing there was a real piston at the other end of it! (I have it bookmarked - lol.) I've also read mixed reviews about M and D, but they were pleasant to deal with and up front about their payment requirements if I chose to take my chances ordering the piston. The real irony is that they're only 40 minutes from where I live and I'd have been there in a heartbeat if that rascal was actually sitting on a shelf.
The search continues but I haven't given up on possibly cleaning up the one I have. Problem now is getting the circlips out (or at least one) to remove the wrist pin so I can work on it. At least it takes the 87854 rings if I decide to put in new ones. Wonder if 12mm clips will work if I launch one of those into orbit...
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PogoInTheWoods said:
I'm looking for possible options to replace the piston in my Mac PM8200. It's the last of the 82cc Macs and a departure from the previous design in that it uses a three piece crank with circlip style pin bosses for the piston vs. the earlier press fit pins..., which is why none of the other 82cc Mac pistons will work. NOS seems to be non-existent for these things and there weren't even that many PM8200's made, let alone spare parts for em (unless they're hidden in a warehouse somewhere). Production was pretty much at the end of the line for McCulloch as most folks remember McCulloch right about this time. Then it all went south shortly thereafter.

Anyway, any suggestions for 52.4mm piston solutions out there?

TIA in advance for any info or enlightenment.
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Actually, should have just cleaned up and used the original piston with a new set of rings a lot sooner than I eventually did. The whole process was pretty well documented in the Mac thread and I'm very happy with the result. Also learned a lot.

When I talked to M and D they wanted payment up front with no guarantee that they could even come up with anything more than their little picture of the piston. Sorry. I've read too many less than stellar comments about them to just fork over 90 dollars for who knows how long to 'maybe' end up with a product they advertised but didn't actually stock. Sure as hell didn't want to go around in circles with them to get my money back if they couldn't deliver in a timely and professional manner..., which seems be one of the occasional shortcomings of doing business with them according to certain sources.

Glad you got your piston. But maybe you should have thoroughly digested my PM8200 rebuild in the Mac sticky and possibly saved yourself 90 bux?
 
PogoInTheWoods said:
Actually, should have just cleaned up and used the original piston with a new set of rings a lot sooner than I eventually did. The whole process was pretty well documented in the Mac thread and I'm very happy with the result. Also learned a lot.

When I talked to M and D they wanted payment up front with no guarantee that they could even come up with anything more than their little picture of the piston. Sorry. I've read too many less than stellar comments about them to just fork over 90 dollars for who knows how long to 'maybe' end up with a product they advertised but didn't actually stock. Sure as hell didn't want to go around in circles with them to get my money back if they couldn't deliver in a timely and professional manner..., which seems be one of the occasional shortcomings of doing business with them according to certain sources.

Glad you got your piston. But maybe you should have thoroughly digested my PM8200 rebuild in the Mac sticky and possibly saved yourself 90 bux?
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guess i got lucky with mine and there was no saving that piston never seen one that trashed even the rings were trash dont know how the cylinder survived with minor damage and i was pissed when they said they didnt have it after i paid for it but took the chance wasnt like they wouldnt give me my money back so i let it sit with them while i kept looking but i wouldnt deal with them again for sure and im glad you got yours running

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