Piston Expanders?
 

Man, I never heard of this in my life. Since there's eight in a set I guess you installed them and ran with them? I'll see if I can link to ebay:

http://www.ebay.com/itm/Piston-Expan...53.m1438.l2649

Re: Piston Expanders?
 

Very interesting, never heard of such a product.

Re: Piston Expanders?
 

So far, looks like Google never heard of em either.

Re: Piston Expanders?
 

Sounds like you two boys missed out on the good ol' days! These were a common item back in the day.

Re: Piston Expanders?
 

The instruction sheet is interesting as well! Perfect Circle no less.

Re: Piston Expanders?
 

Ranks up there with Motor Honey, Spark-O-Matic and Water Injectors.

Re: Piston Expanders?
 

Lean new stuff every day!!! https://docs.google.com/viewer?url=p.../US2341959.pdf

Re: Piston Expanders?
 

Yep, just one of the tools that were available to install 'knurled' surfaces on the skirts of pistons to decrease the cylinder wall clearance.
Witnessed and participated in a number of engine 'overhauls' using this method.

Re: Piston Expanders?
 

Why does the description say "reproduction?"

Re: Piston Expanders?
 

Lot´s of ways to "fix" things if labor was cheap.
Grinding pistons to undersize and reusing.
Piston ring regroover and steel shims.

Re: Piston Expanders?
 

Isn't that a question for the seller of the product? :confused:

Re: Piston Expanders?
 

I had pistons expanded by shot blasting back in the 70/s.

Was a normal everyday job then.

Re: Piston Expanders?
 

You can´t get material worn away back again so what you get after knurling is a piston with less lifespan then a new one.
Back when labour was cheap and lack of parts was an issue i can get "fixing" stuff.

Re: Piston Expanders?
 

Sure, when an engine is rebuilt new pistons are used but when it is overhauled, knurling the piston extends it's lifespan, at a lesser cost. Call it the cheapest way but that's what people wanted, and it worked.

Re: Piston Expanders?
 

Perfect Circle had a knurling attachment for the lathe to knurl the skirts that would work for a while but today the hot setup is have the skirts coated by Swain Tech .
They can build up the skirts a couple of thousands.


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Re: Piston Expanders?
 

I had a '70 Triumph 500 in the early 80's that had knurled pistons. I took it apart for other reasons, but it ran fine. First time I had seen them.....Mark

Re: Piston Expanders?
 

There were lots of ways to do the cheapest possible service on an engine - to get it back on the road and in the process, spending the least amount of dollars. Dang near every small town had somebody who "rebuilt engines" . . . everything from lawn mowers, to tractors, to cars. People didn't have money to spend and there was a lot of cheap labor available (young 'blue collar' folks) - without XBoxes, Computer Games and Texting to distract that 'cheap labor'. LOL

Re: Piston Expanders?
 

I had a set of original Mopar piston expanders just like these for my 50 Plymouth but I didn't use them when I had the engine apart because the pistons still checked out very close to factory specs.

Re: Piston Expanders?
 

I have heard of knurling a piston to decrease the slop but these things I have never seen. So if I read it correctly, they actually expanded the piston, did these thing really work?

Re: Piston Expanders?
 

I also knew about knurling, and have seen the little tooling parts for it. Then it looks like there was a setup for expanding pistons before you put them in. But these deals are a whole new idea for me.