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.

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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.

Re: Piston Expanders?
 

We tore down a Model A engine a couple of months ago that had those in the pistons. Had no idea what the were for.

John

Re: Piston Expanders?
 

They would only work on a split skirt type piston. Not sure if they were intended for steel pistons or aluminum or both. I don't particularly like the idea of expanding an aluminum piston that way. Some piston skirts fail without any help like that. It doesn't make much sense to help them fail in my way of thinking.

Re: Piston Expanders?
 

Back in the day, piston expanders were common. Various approaches. I remember ones that were made of spring steel and worked on the piston pin bosses to encourage that part of the piston to expand. Had to be installed with special pliers to get them properly in position. Seems to me I used them on the flathead six in the family '48 Dodge. Might have bought them from Montgomery Ward.

Re: Piston Expanders?
 

When I learned engine repair lots of years ago...we were taught how to knurl piston skirts...then we would undercut the ring grooves and install what was called "expanders" it really worked well...the knurling not only made the skirts expand but held oil in the skirt area... It was cheep and common in the 40' and 50's

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Things have reversed over the years. I have a 1947 Motor Manual that also has a labor and parts section. For example , a lot of new pistons were listed for around $10 each, while labor rates were around $2.50-$3 an hour. So it was cost effective to "rebuild" a piston by knurling/resizing/expanding, cutting the top ring groove and installing a spacer, and honing the wrist pin bore (and rod) for an oversize pin. If the cylinder bore had a lot of taper, you just cut the ridge with a ridge reamer and maybe put expander springs behind the rings. I remember overhauling a few engines with as much as .019" taper and they ran pretty good with no smoke or oil burning so I set .019" as my limit on wear before needing a rebore.
Today, you can still find a new piston for a 350 Chev or 302 Ford for around $10 (imported, true) while labor is $80-$100/hr.
And don't forget the tapered shims for worn bearings and/or crankshafts! These were sheets of brass shim stock that was, for example, .002" in the center and .001" on the edges. So you cut a strip the width of your bearing insert and put it under the lower insert. By being .002" in the middle and .001" on the sides, it took up .002" wear evenly. It came in different thicknesses.

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I have some of the piston expanders that are new. They were used in the steel pistons to eliminate piston slap. That is what I was told by an old time mechanic. He did not mention using them in aluminum pistons.

Re: Piston Expanders?
 

I kinda hesitate to tell this, but my Dad told me back during the Great Depression he used bacon rind for rod bearings. I got a big laugh out of it and asked him how that worked. He told me the old Model T' didn't run fast, and they didn't drive them very far because they couldn't afford gas. When they started knocking they just replaced the hog rind bearings. I still smile to myself and think how hard it had to be in those days, I still have a pic when I was 2yrs. old wearing a gown, because that's all he could afford and mother made that. Al

Re: Piston Expanders?
 

That's new one one me, too. When I was a Ford mechanic sixty years ago, we regularly had pistons knurled on an in-house overhaul if the owner wouldn't spring for an "authorized" Ford rebuilt engine. I suspect the "expanders" would adversely affect piston weight.

Re: Piston Expanders?
 

Funny stuff.....I wonder If we can extend the life of Babbitt bearings using Bacon?

Re: Piston Expanders?
 

I have hear tails that some guys who experienced rod bearing problems on model T's, while on the road, would cut sections from their leather belts to make a temporary repair.

Re: Piston Expanders?
 

piston expenders were installed in the piston. the theory was when the eng got hot the steel expender would expand thus increase the piston dia .years ago we did a lot of in frame eng rebuilding it was cheaper. did it last where i was most cars were driven in the city at slow speeds & yes they held up well. we did not use crome rings as they were hard to seat. money was tight. no credit cards. most house holds had onley bread winner.no body had 90 dollar shoes or 500.00 cell phones

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As Bored&Stroked has posted we as a nation were not always a throw away society. During WWll & the depression you made do. Folks today do understand that. Just get on the smart phone & order a replacement made off shore.

Re: Piston Expanders?
 

Years ago I used knurled Pistons to tighten up slightly loose Pistons and they lasted a long time. One trick was knurl them heavy on the coast side of the piston and not on the thrust side to make em last longer. Machining the ring grooves was also common because if the piston has very little wear on the skirt truing up the ring groove and installing spacer rings was also acceptable. What happens if the engine you are working on has very expensive and or very hard to find Pistons ???
If it works do it. An out of round or tapered cylinder is worse than a fairly straight cylinder with slightly loose Pistons. The rings don't last long if taper is bad and don't seat very well if out of round.