Piston Question

[Cantdog]

So.......I just got this new Meteor piston. It's for an open port Husqvarna 268. I have never put a new piston in these open port saws (non windowed piston) but have put many in the closed port versions. Right out of the box I noticed the lower 1/4" or so of the skirt was smaller diameter than the upper skirt. It measures about 0.010" less than the upper part of the skirt. I could see it and feel it with my finger. I have a few new windowed Meteor pistons here for the 268XP, 272 XP and 262 XP....they do not have this relief as they measure the same the whole length of the skirt. So my question is......Do I have a bummer piston or are they supposed to be this way? I doubt it will affect the running of the saw but not having the skirt supporting the piston the whole length will contribute allowing the piston to rock more than usual.........OR is this a wear indicator telling you when the whole length of skirt is in contact with the cyl it's time for a new piston........seems a bit far fetched to me.........what are your thoughts???

For the record I'm a pretty good fan of Meteor piston by and large.

 

[Fordiesel69]

The thousandths are=

1.967 tapering to 1.956

 

[Cantdog]

The thousandths are=

1.967 tapering to 1.956

Yeah so 0.011" more or less what I said

 

[hotshot]

Wow, that can’t be right, as the intake port would spit a geyser back like Old Faithful!

Send the bummer back for an exchange, there should be a taper larger towards the bottom on the next one you get, by about 0.003”.

 

[Mad Professor]

That piston is screwed up. Taper should be from bottom/widest to top/narrowest.

I measured this on NOS 038M pistons (52mm) from Stihl and Tecomec (Italy), using a quality micrometer not calipers.

Bottom to top tapers were 0.006 and 0.005", respectively.

I'd send it back

 

[Cantdog]

I should clarify.........the piston has a taper of about 0.001" from bottom of the ring land down to where this wierd taper starts......as per most normal pistons.....as I said it will likely run fine......this is not a high performance saw......and not for a logger....just a homeowner........he bought it as an XP........but on tear down it was not.......likey had been once but not now.

 

[Modifiedmark]

This sounds strange to me. I think I would contact Meteor and see what they say. Like you I have never had a issue with a Meteor piston.

 

[huskihl]

I think you got a Friday pm piston there, Robin. Return it for a replacement

 

[Cantdog]

Wow, that can’t be right, as the intake port would spit a geyser back like Old Faithful!

Send the bummer back for an exchange, there should be a taper larger towards the bottom on the next one you get, by about 0.003”.

True........It would tend to freeport a bit with no seal at the bottom of the skirt which sets your intake timing......

 

[Cantdog]

So.......sent the above pics and clear, polite explanation of the problem to the seller......we'll see where this goes...

First ever problem with a Meteor piston for me.......everyone's input was about the same as my thought's on this.

Likely a Friday PM piston for sure!!! LOL!!

 

[Cantdog]

So.......sent the above pics and clear, polite explanation of the problem to the seller......we'll see where this goes...

First ever problem with a Meteor piston for me.......everyone's input was about the same as my thought's on this.

Likely a Friday PM piston for sure!!! LOL!!

So....the seller got right back to me and is sending a replacement ASAP...no questions asked.....hopefully the replacemernt isn't the same!!!

 

[Fordiesel69]

I was curious of something. Depending on the calculators I used online, did you determine if the the difference was ONE thousandth off, or ELEVEN thousadths off. I interperate your initial post as ELEVEN.

 

[Cantdog]

I was curious of something. Depending on the calculators I used online, did you determine if the the difference was ONE thousandth off, or ELEVEN thousadths off. I interperate your initial post as ELEVEN.

I used the conversion built into the calipers........measured in mm and hit the button to convert to thousandths.....subtract the smaller from the larger .....and yes Eleven thousanths shy of the correct measurement. As I said you can see the difference in the machining with the naked eye, which is how I even noticed it in the first place.

 

[Lightning Performance]

I used the conversion built into the calipers........measured in mm and hit the button to convert to thousandths.....subtract the smaller from the larger .....and yes Eleven thousanths shy of the correct measurement. As I said you can see the difference in the machining with the naked eye, which is how I even noticed it in the first place.

You did it right by checking a suspect part.
Had a Meteor come up short before 0.010 in height so it was a mistake that didn't hurt anything. Having tight wrist pin bores happens. It's usually the bur from the clip slot being cut and not reamed or honed. Once installed the pin should float freely.

 

[lone wolf]

That junk must be really made in China not Italy. What say all you smart people?

 

[Cantdog]

That junk must be really made in China not Italy. What say all you smart people?

Just the bottom 1/4"was made in China......

 

[lone wolf]

Just the bottom 1/4"was made in China......

Well luckily you had the presence of mind to catch this before installation.

 

[Cantdog]

Yeah

Well luckily you had the presence of mind to catch this before installation.

Yeah....I could see and even feel it with my finger as soon as it came out of the box.....measuring it with capliers really showed the problem.......at least within 0.001" or so.

 

[ballisticdoughnut]

The one meteor piston I’ve purchased was good, just didn’t fit in the cylinder very well. OEM Mahle and KS cylinders were graded A, B, C, and D. If you get the wrong grade of piston (which I did) they’ll either be too tight or too loose clearance wise. Other than that the quality of the piston was pretty good. Casting was nice, machine work was nice as well.

 

[grizz55chev]

I've purchased dozens of Meteor pistons over the last few yrs, never got one with that particular box, and marked in that fashion. Could be a clone or knock off!