Piston Rings for Vintage Saw

[danwest8038]

I've started to tear down an old 1953 McCulloch Model 33 chain saw. I'm guessing it has been sitting for 20 or 30 years, but everything inside looks to be in pretty good shape. I've pulled off the cylinder to clean the mud dauber nest out of it (they entered through the exhaust), but snapped a piston ring trying to pull that off.

While I know that I can get one pulled from an old saw, I'd much rather not use 60 year old rings. Does anyone know where I can get piston rings by size? The bore is 44.4 mm and the thickness of the broken ring is 1.58 mm. Is it likely the original right was 1.6 mm thick? Any information you can offer is appreciated.

 

[DJ54]

There are a couple NOS sets on ebay right now.

 

[bcp]

That's probably best.

Search on ring mfg. sites for lists.

Some examples, but these may be too large for your saw

By diameter
https://www.hastingsmfg.com/RingFinderDiametrical.aspx

By part number
http://www.grantpistonrings.com/catalog/Numerical_Listing.pdf

Bruce

 

[danwest8038]

Sorry for my ignorance, but what does NOS stand for and what did you search on eBay? Unfortunately, there is a lot of unknown and confusion about parts compatibilities between the early McCulloch chain saws, so a search turns up quite a few incompatible parts. Maybe I'm just searching wrong.

As for the ring manufacturer links, I'd already looked at those two. I didn't see anything compatible. I did find a Stihl piston ring set that was close, but just shy of fitting.

Anybody know a good small engine store that might be able to find them?

 

[Winmac]

Nos=New old stock.

 

[danwest8038]

Nos=New old stock.

That's what I figured. Wouldn't that exclude used parts? I ask because New Old Stock McCulloch 39 33 35 Chainsaw New Piston. Check the image.

 

[Winmac]

The piston in the picture appears to be unused although not in new condition.
The term is overused on a lot of advertising, even misleading most of the time.
I don't know much about old Mac's but would metric have been the unit of measure back in 53?

 

[2458n]

You are right the old Mac's were built in the US. At one point I read a article about the company going to build a town out west to support a factory.

 

[danwest8038]

Good point. Since the Metric Conversion Act was in 1975 and McCulloch was American based in 1953, it likely would have been measured in inches. However, ordering new today, should that matter?

According to Mc Bob, the Super 33 (reported as being almost identical, larger air filter) has a bore of 1.750".

 

[DJ54]

Sorry I didn't follow up sooner. Both are still listed, here is the link:McCulloch 33 piston rings | eBay