To grind piston skirt exhaust side or not?

[EvilRoySlade]

Specifically I have a 372xt I'm working on. There is a 1/2" material before free port could happen. In my opinion most all of the skirt stress happens on the intake side. It's a heavy piston to start with so I was thinking of removing some of the exhaust skirt, about a 1/4". It would lighten it some, taking stress off the bottom end. If I go gently and chamfer I think it would be fine. I know it would change balance front to back but I have a hard time believing it's balanced stock.

Any experience or ideas?

 

[paragonbuilder]

I'm not sure, but I like how your thinking!
Subbed


Sent from my iPhone using Tapatalk

 

[paragonbuilder]

What is the purpose of the Saw?
If it's a work saw I think it's not worth it.


Sent from my iPhone using Tapatalk

 

[Termitebuffet]

That piston length also prevents rocking. ...

 

[EvilRoySlade]

I was considering the rocking but my counter thought is it's a tall piston with lots of support on the exhaust. Also it seems by looking at wear patterns that the exhaust skirt really doesn't do much rubbing on the cylinder.

It's going to be a work saw but I only cut for my firewood and for fun. I'm keeping the limited coil so I don't have to stress about high RPM.

My biggest worry is breaking the piston. I am having a hard time believing that a 1/4" off will do that. Of course anything that's touched can break and usually gets blamed it was touched. No matter what I am going to work over the piston to remove as much aluminum as I feel safe doing. Not racing style, just weight reduced. The 1/4" is just a nice big chunk.

I'll give it a few days to see if anyone chimes in with a negative report of such behavior.

 

[EvilRoySlade]

Here's the piston currently.


The red mark is bottom of exhaust port with piston touching squishband.

Aren't some newer Stihl pistons uneven skirt heights intake to exhaust?

 

[tickbitintn]

looking at your pics it seems well thought out and sounds reasonable to me....
subbed!!!

 

[EvilRoySlade]

On forestry forum Ed Herd mentioned he won't cut skirts cause he has seen failures near grinding/cutting points but he does grind as much excess casting as possible. Especially the strato channels.
As of now I won't cut the skirt. I did some looking at pics and I see the 261 and 562 have offset skirt heights. So it's not abnormal but those pistons were cast that way.

 

[Skinman]

So what ever came about on this? Did you ever try it?