Stihl ms181 piston - oem or not? Help needed

[MartDalb]

Hi everyone.

Yet another saw on the bench.
A Stihl ms181 from 2014.

No idea of background on this.
Just would not run correctly.

Took the engine out, looking at the piston I can't make out if the piston is original or not.

It looks kinda dodgy to me, in the bottom part.
What do you think?

Every other part on it, is Stihl Oem parts.

See picture.

 

[MartDalb]

Oh and it does not have a Stihl logo imprinted on the top of the piston.

Don't original pistons from Stihl always have this?

 

[huskihl]

I believe they’re made in China. It’s probable that oem parts are run of the mill chinese stuff in a sub-$200 saw

 

[MartDalb]

I believe they’re made in China. It’s probable that oem parts are run of the mill chinese stuff in a sub-$200 saw

So, piston and rings looks fine. Ill post pictures.

If so, ill just go ahead and rebuild with new gasket and new oils seals.

Still think quality is poor on this piston, strikes me odd, but Stihl has been doing some junk stuff, from time to time, for sure.

 

[MartDalb]

More pictures added

 

[SteveSr]

More pictures added

Ears on the circlips is a give away for non-Stihl OEM... unless Stihl has changed their M.O. The gap needs to be facing either up or down... not sideways!

BTW, I didn't know that there were any AM P&C for the Stihl "xx1" saws. If that is an AM piston that could be your running problem due to excessive squish clearance. Might check the jug for OEM markings. AM jugs are known for poor quality and bad port timing.

 

[MartDalb]

Well

Ears on the circlips is a give away for non-Stihl OEM... unless Stihl has changed their M.O. The gap needs to be facing either up or down... not sideways!

BTW, I didn't know that there were any AM P&C for the Stihl "xx1" saws. If that is an AM piston that could be your running problem due to excessive squish clearance. Might check the jug for OEM markings. AM jugs are known for poor quality and bad port timing.

Well that is a dead giveaway then.
I will check the cylinder, I do think this WAS a running saw though, with all the dirt and stuff on it.
Meteor 181 pistons looks very nice, might get one of those if the cylinder checks out.

 

[MartDalb]

Had a look at the bearings as well. Those are not original either, almost sure.

Will post pictures later.

 

[MartDalb]

Here are the bearings. I dont recall seeing that kind of inner red holding part on oem bearings?

 

[Lightning Performance]

Here are the bearings. I dont recall seeing that kind of inner red holding part on oem bearings?

Those are plastic caged Stihl OEM bearing.

 

[MartDalb]

Those are plastic caged Stihl OEM bearing.

Well that sounds good! Haven't seem em like this before, might have slipped my sights tho!
Thank for the reply!

 

[Lightning Performance]

Well that sounds good! Haven't seem em like this before, might have slipped my sights tho!
Thank for the reply!

I've only seen them in smaller saws but my 066 should have those still in it. I can check when the jug gets swapped this winter. Got one to weld up the chamber and spark plug hole. It's already been machined and prepped for work.