Resizing a chainsaw piston?

[idiotwithasaw]

Is it possible in the case of say an odd sized piston, such as a 51.4 mm 372xpw, to buy an oversized piston that has the skirt width, length and crown height you would want and turn it down to size?
Has anyone done this, and what would be the benefits and or disadvantages? Too thin of a wall? Uneven cut?
I'm thinking this as a solution to pistons that don't have quality aftermarket options.
As I write this I already can think of a few issues of doing this but I want to hear you guys thoughts.

 

[DSS]

You'd have to recut the ring groove, and I'm thinking you'd run out of meat. Also the pin bores and c clip groove

 

[beaglebriar]

Sounds like a huge pita.

 

[Gentleman]

Maybe easier to buy the OEM piston.

 

[idiotwithasaw]

I'm also looking for a somewhat cheaper option, assuming you have access to the tooling. But also if you are looking for a wider skirt, or a taller crown for modding. I don't see taking .6 mm off diameter so only .3 mm of material being removed causing the circlip grooves needing to be recut. I can see the ring pins being an issue and was actually one of my first concerns, as was the ring groove, but if we are talking a custom piston, that's part of the deal and probably want to move them anyway.

Sent from my HTC One using Tapatalk

 

[beaglebriar]

I think Wiseco will build custom pistons. Probably spendy though.

 

[idiotwithasaw]

I think Wiseco will build custom pistons. Probably spendy though.

Yeah, but what's the fun in that.


Sent from my HTC One using Tapatalk

 

[beaglebriar]

Yeah, but what's the fun in that.


Sent from my HTC One using Tapatalk

IDK??

 

[idiotwithasaw]

Need to find a meaty enough used piston to try this on.

 

[DSS]

I think Wiseco will build custom pistons. Probably spendy though.

There was a run of pistons made by them not long ago, somewhere around $100 each but you had to buy 10 or 12 I believe.

 

[idiotwithasaw]

Yeah there are some on the bay for $100 but that's the 50mm. The 51.4 isn't made in any form of aftermarket as far as I know.

Sent from my HTC One using Tapatalk

 

[mdavlee]

Wiseco is 12 minimum. Paying for a design and forge on the first run is around $4-500. Puts 12 pistons in the $1900 range

 

[idiotwithasaw]

Dag gone. Unless you are planning on building a bunch of hot saws that's a little pricey

Sent from my HTC One using Tapatalk

 

[mdavlee]

Dag gone. Unless you are planning on building a bunch of hot saws that's a little pricey

Sent from my HTC One using Tapatalk

If they have a forge that part is out of the cost. Still $100-135 a piston depending on options on it.

 

[Al Smith]

It isn't as simple as just turning the piston down with a lathe .First let me say I've worked on one piston line for Honda and 4 for Ford and it goes like this .

The top portion of the piston is perfectly round but the skirt has a slight taper and ovality .Modern methods use CNC machinery .Older methods used a "cat head " turning lathe .To attempt to turn down a piston in a standard lathe would be a feat I myself wouldn't try .
I have a Monarch 10" EE lathe which unfortunatly is not running at the present but if it were it's one of the best toolmakers lathe ever built .It has a taper attachment but I have no idea even using this fine machine how a person could ever cut ovality with it .

 

[super3]

^^^^^^^
This.

 

[idiotwithasaw]

This is good information.

Sent from my HTC One using Tapatalk

 

[bwalker]

Pistons are taper ground from top to bottom and cam ground front to back. Simply turning a piston down on a lathe might not work so well.

 

[idiotwithasaw]

I would love to see a video of this process.

Sent from my HTC One using Tapatalk