Piston failure in a ported cs2253 Jonsered

[BTO']

 

[huskihl]

Looks like some detonation going on. Likely from old stale fuel

 

[Michpatriot]

Ill second the bad fuel...and add that the pop up pistons with the squared off sharp corners have always erked me, when they are at TDC you have those corners and the corners of the combustion chamber squish band in close proximity.. Detonation is multiple flame fronts in the chamber colliding.. When you have the squish band edge and the popup edge reflecting the flamefront at different angles it seems like a recipe for disaster. Octane may cover this up and keep detonation away but loose a point too much and your in the expensive noise department quicker than you can react. I really am sold on flat top pistons that are paired to a nice squishband. Two strokes seem to defy logic when it comes to cylinder pressure and low octane as long as the piston is flat and the squish band and combustion chamber are set up perfect. Look at the top of the piston on the pop up, to my eye there is evidence of the detonation flame front in the wash pattern and the edge of the popup became the hot spot..and it went downhill from there..Then again I could be all wet..but do I know that these similar looking piston failures in drag racing engines sometimes start with just a sharp edge on valve reliefs and go from there..its like vaporized aluminum is the fuel that detonation uses when there ain't octane. I've seen several race engines that had their best\last pass on aluminum. My brother and I used to have a running joke that they run the best on aluminum.

 

[blackbruin]

Looks like ethanol fuel that's set for a while and soaked up some moisture.

 

[Stump Shot]

I'd say after studying the pictures for a spell that it's a simple lean failure. That is if those speckles are melted aluminum droplets sticking to the piston and not pock marks. The cause of such failure could be many, the saw should be pressure/vacuum tested before put back into service after repairs made, so as not to repeat the problem.
Big question is, can the cylinder be salvaged???

 

[BTO']

If I rebuildit does anyone think it will fail again?

 

[BTO']

The cylinder is repairable with some acid cleaning.

 

[Stump Shot]

If I rebuildit does anyone think it will fail again?

Very probable if the original cause of the failure isn't taken care of.

 

[BTO']

Speaking of race pistons. I know there are different heat rated pistons like for turbo/non turbo vehicle engines. Are there 2 stroke pistons of this type... heat dissipation/aluminum alloy pistons? Or does it matter in a ported set up since the piston is milled and there is less material?

 

[Timjus]

isnt this autotune saw.
piston looks very dry like its been run without oil in gas

 

[BTO']

It is autotune. The intake side of the piston has oil residue. The exhaust side has no oil residue. All my saws run 50:1. I have 4 chain saws. Been a wood cutter for 33 years never forgot the oil mix. Never had a saw fail like this.

 

[Stump Shot]

A lack of oil failure affects all sides of the piston, including the intake. Whereas a lean failure tends to just affect the exhaust side mostly.

 

[huskihl]

I’d inspect your seals, case bearings, and your transfer cap o-rings for leakage

 

[BTO']

Another question: I have seen pop up pistons for sale on ebay. Are these manufactured pistons equal to a milled piston? Is one better that the other or are they equal in durability?

 

[huskihl]

Another question: I have seen pop up pistons for sale on ebay. Are these manufactured pistons equal to a milled piston? Is one better that the other or are they equal in durability?

A milled, or forged, piston would be like a Wiseco. The others are all cast. Oem or Meteor are decent quality. Hyway or Duke’s are close. The rest are a crapshoot

 

[huskihl]

You’d need to find out if machine work was done to your piston and cylinder to determine if your piston is oem and had a popup cut into it or if it’s an aftermarket piston with a popup cast onto it

 

[Hall84]

Or you could just let me take it off your hands. Then I’ll send it to huskihl, for a little TLC. Been wanting a 2253 lol.