044 Ring failure with Espian piston kit

[Brushwacker]

I've been quite disappointed the last 2 days. I had put a new Episan piston kit in my old 10mm 044 last summer. It had been running fantastic since, I did file a little around my ports then polished the exhaust nice and smooth with emory cloth. The saw had teetered with around135 lbs of compression since I bought it off ebay about 3 years ago being dependable but didn't have near the power that it did after I replaced the piston and rings with the slight modification to the ports last summer. My freind run it who has a year old 372 and was surprised and commented it felt close to his. Well I imagine I haven't put maybe around 30 hours on it , little more or less and yesterday it wouldn't idle, just died when I let off the throttle. I noticed compression felt very low and thought maybe I burned a hole in the piston as I had the plug out a few weeks ago and it looked quite a bit gray, but then I richened it up a bit and it sounded safe. So tonight I pulled the cylinder and both rings were broke in half. Anybody know what usually causes it ? Cheap rings with the Espian piston ? Piston -cylinder clearance wasn't awful bad when I put it in, but not as tight as a newer cylinder would of been. If memory serves me right it was .004 to.005 which I thought would be ok. Nothing looks like it run hot and there was a very thin, light film of dark carbon on top and in the exhaust, not enough to flake off.
If any one can help me out why the rings probably broke I would appreciate it ?
I located an brand new oem 10mm P&C on ebay, checked the seller, bid $75.65 yesterday and came back tonight to up the bid at the end of the auction, being I could really use it I bid way over that with 15 seconds left and thought I had it as the page returned with 4 or 5 seconds, thought it said I won and I went to my ebay and listed it as an item I didn't win sold for $76.65 + about $10 shipping. I bid about twice that and thought I had it for the $70 something :msp_mad::msp_mad: . Was thinking of installing it this week already after I thought I won the bid and now I gotta figure what to do with what I got, and after the short life of those rings I guess its big bucks if I go oem. The espian piston has a long straight scratch so don't know I would want to use it and the cylinder I think is on the edge of its limits but I suppose I'll get some second opinions.

 

[blue dog]

I bid $55.55 and was going to come back in the last seconds but forgot untill I got a email saying sorry you didn't win. sold for $76.75 someone got a deal

 

[blue dog]

A you sure you confirmed your bid?

 

[Jacob J.]

Typically when I would see broken rings in the shop it was because the saw was run overspeed or in a lean condition for a period of time. I know some of the Bailey's pistons had issues for a while with brittle rings.

 

[tlandrum]

need pics to give opinion

 

[Jacob J.]

A you sure you confirmed your bid?

That's happened to me as well. I was bidding on some 090 parts last week and I put in a bid during the final eight or so seconds. The auction ended and it said I had won. I refreshed the page and someone else had won.

 

[Brushwacker]

A you sure you confirmed your bid?

1 click bid, I thought that was it.

 

[Metals406]

1 click bid, I thought that was it.

Nope, then you click "confirm".

 

[Brushwacker]

That's happened to me as well. I was bidding on some 090 parts last week and I put in a bid during the final eight or so seconds. The auction ended and it said I had won. I refreshed the page and someone else had won.

Thats about what I thought only I went to pay. Thought all my o44 problems were relieved and then the hurt came back triple.

 

[Jacob J.]

Thats about what I thought only I went to pay. Thought all my o44 problems were relieved and then the hurt came back triple.

What I'd do if I were you is try one of Bailey's NWP pistons for the 10mm wrist pin 044 along with a set of Caber 50mm rings. The current generation NWP pistons are excellent and I've had great luck with them. I helped a buddy rebuild his 10mm wrist pin 044 with one and it turned out to be a great runner and has about six months on it now.

 

[Brushwacker]

I don't remember if I clicked confirm, o well.
The 044 was pretty much screaming with good acceleration and power and had a little black carbon film on the exhaust outlet so I didn't think it was to lean but the high RPM's felt like my freinds 372 wide open. I wonder if oem piston and rings would of faired much better ?

 

[Jacob J.]

Maybe, there's no real way to tell. I've had excellent luck with the 25 or so Episan pistons I've installed, but in your case the most cost effective option is the Bailey's piston. Plus the Bailey's pistons are coated which helps with break-in.

 

[67L36Driver]

O.P.: What was the ring end gap?

Too little end gap will break rings every time.

 

[maico490]

OP stated 0.004 to 0.005 which I've used as a rule of thumb for end gap per inch of bore. I don't know what the bore of a 372 is off the top of my head but it is certainly more than 25mm which would make the end gap too tight.

 

[67L36Driver]

OP stated 0.004 to 0.005 which I've used as a rule of thumb for end gap per inch of bore. I don't know what the bore of a 372 is off the top of my head but it is certainly more than 25mm which would make the end gap too tight.

Piston -cylinder clearance wasn't awful bad when I put it in, but not as tight as a newer cylinder would of been. If memory serves me right it was .004 to.005 which I thought would be ok.

I bet he never measured it, end gap that is.

 

[Blowncrewcab]

I was bidding on a Chemical Pump for my Chlorinator (at the Last Second) and wanted to bid $80.00 But I hit the comma instead of the period and it went to $80,000 and I didn't notice and hit Okay, Needless to say I won that pump. (for like $110.00) I was gonna win it no matter what with that bid

 

[maico490]

I bet he never measured it, end gap that is.

I got my post around my ear. It was the piston/cyl clearance he measured and the 372 was his friends saw.

 

[splitpost]

I was bidding on a Chemical Pump for my Chlorinator (at the Last Second) and wanted to bid $80.00 But I hit the comma instead of the period and it went to $80,000 and I didn't notice and hit Okay, Needless to say I won that pump. (for like $110.00) I was gonna win it no matter what with that bid

:hmm3grin2orange:would have been screwed if someone bid 75 and made the same stuff up,now that would be an exy pool pump

 

[Brushwacker]

I am certain I checked the ring gap, and thought it was ok but don't remember just what it was. It did work fine about 30 hours give or take some.
I looked it over more closely today and noted the machining below the rings showed very little wear on the piston, but above the ring grooves it was smooth without the machining marks. Other things I considered, (the rings broke each in half about mid way) I bought a case of old Stihl 40 to 1 mix a couple years ago and was just getting around to using it often about a year ago when my original piston broke a chunk between the rings. Since I put the new piston in probably 3/4 the the fuel I used was with the same oil. Also the thin film of carbon was hard enough to flake off and looked like a little did come off the top of the piston which I believe may acounted for the wearing the machining off above the ring grooves. I never put it on a tach but it was cranking up on the high side so probably a combonation of not so good things was to much for the rings . I rechecked the piston to cylinder clearance and it was .003 to .004 . .I believe the cylinder looks fine. The piston has a very shallow line most the entire length and I think its usable but I am not sure it wouldn't be significantly better to replace it. If I don't find a deal on a nice oem maybe I'll try NWP from Baileys.
While I'm thinking of it , what is the ideal ring gap.

 

[Brushwacker]

I was bidding on a Chemical Pump for my Chlorinator (at the Last Second) and wanted to bid $80.00 But I hit the comma instead of the period and it went to $80,000 and I didn't notice and hit Okay, Needless to say I won that pump. (for like $110.00) I was gonna win it no matter what with that bid

Did the same on a chainsaw chain once. Hope we don't ever bid against each other !