dce1843
ArboristSite Operative
I'm about to order a aftermarket piston for my echo 670. Some of them have only 1 ring while others have 2. My original had 2. Does it really matter ?
2 or 1 ring piston pros and cons?
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Allen K
Chainsaw Addict
My first thought, and I probably only know enough to be dangerous, was that two rings are better. After reading this, I'm not so sure:
http://www.arboristsite.com/community/threads/1-piston-ring-or-2-piston-ring-whats-better.184469/
I'll be interested in reading the responses and learning a little more from those who know what they are talking about. We have an Echo CS-280e that needs a piston and we seemed to only find the single ring type.
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http://www.arboristsite.com/community/threads/1-piston-ring-or-2-piston-ring-whats-better.184469/
I'll be interested in reading the responses and learning a little more from those who know what they are talking about. We have an Echo CS-280e that needs a piston and we seemed to only find the single ring type.
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One. The second ring creates a significant amount of friction. It's only beneficial on a saw that sees hundreds of hours of use and can add longevity to the life of the engine.
Less friction, weight and normally better performance with one ring.
Two rings may give you slightly better compression, piston stability, heat transfer and durability.
There's really no need for two rings, and I personally haven't seen the benefits I listed above.
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Two rings may give you slightly better compression, piston stability, heat transfer and durability.
There's really no need for two rings, and I personally haven't seen the benefits I listed above.
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I have tested with both one and two rings on the same piston. There was little to no change in compression and the saw gained a few hundred RPMs without the extra friction.
dce1843
ArboristSite Operative
Sounds like I might as well just get the piston with only one ring then. Thanks for the input. I was just thinking it might have a negative impact on compression but I reckon not
tpence2177
ArboristSite Operative
I was actually wondering about this this morning. I noticed most Husqvarna uses one ring, but stihl use to brag on their website on how they use 2 rings. Good info. Thanks!
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Amp4027
ArboristSite Operative
I'd go direct, OEM, part#-off-the-IPL drop-in replacement. That was what the saw was designed and built with, and you know it works.
This is just my opinion: If a newer design has less parts, its usually because the manuf's bean-counters want to bring down production costs and rake in more profit. Count it as hearsay, but I read a thread about a bastard saw design that was both made by multiple companies (Poulan/Craftsman/McCulloch, iirc), and two went the single ring route and both were known to have the piston bounce off the cylinder wall, only the third company had a saw that was actually worth something.
Its your money, so paddle thru the creek at your own pace.
This is just my opinion: If a newer design has less parts, its usually because the manuf's bean-counters want to bring down production costs and rake in more profit. Count it as hearsay, but I read a thread about a bastard saw design that was both made by multiple companies (Poulan/Craftsman/McCulloch, iirc), and two went the single ring route and both were known to have the piston bounce off the cylinder wall, only the third company had a saw that was actually worth something.
Its your money, so paddle thru the creek at your own pace.
Maybe I only know enough to be dangerous also, A single ring should benefit in the cooling aspect as it has more contact with the oil that sticks to the sides of the cylinder. That is compared to the top ring of a two set up. If it came with 2 it has lands inside the cylinder for two different positions of ring ends.
dce1843
ArboristSite Operative
What do you mean by 2 different ring lands in the cylinder ?
Chris-PA
Where the Wild Things Are
Can you link to this thread? What saw?
There's no real benefit to having more than one ring in these two cycle engines. A single ring or thin ring piston is normally considered and upgrade, not the opposite. Some models were made with all the above, the thin ring and single ring variations are the most desirable.
Gypo Logger
Timber Baron
You could get the two ring piston and run just a single ring and have the second one for a spare.
earlthegoat2
ArboristSite Guru
This question ranks right up there with what oil to use and at what ratio.
I find it interesting that longevity is listed a pro for two rings but that one ring is still generally better.
In blowers, I have found that single ring Echos last significantly shorter than dual ring Stihls. I'm fully aware this could have nothing to do with the number of rings on the piston and more to do with air and fuel filtration but it is something to note.
I'm not in one camp or the other but rather I am in the camp of it doesn't really matter. A few RPMs is a drop in the bucket as far as I'm concerned and the supposed increase in longevity has a grin on my face.
I find it interesting that longevity is listed a pro for two rings but that one ring is still generally better.
In blowers, I have found that single ring Echos last significantly shorter than dual ring Stihls. I'm fully aware this could have nothing to do with the number of rings on the piston and more to do with air and fuel filtration but it is something to note.
I'm not in one camp or the other but rather I am in the camp of it doesn't really matter. A few RPMs is a drop in the bucket as far as I'm concerned and the supposed increase in longevity has a grin on my face.
Amp4027
ArboristSite Operative
I didn't bookmark it but I am sure I came across it while trying to find compatible parts for my Craftsman Incredi-Pull 55cc chainsaw. I recall the guy used the word bean counter (or beancounter/bean-counter, etc) in the thread.
To each their own. Personally, I think two rings would help keep a piston aligned (however marginally) & from hitting the cyl wall at higher RPM vs only one, but I am no mechanical engineer.
Would that really work...?
Chris-PA
Where the Wild Things Are
That saw was never a Poulan, nor related to one. No idea if it's been made with both 1 and 2 rings, but I kinda doubt it. I suspect the story is the usual confusion about the various models/designs/brands.
Gypo Logger
Timber Baron
It's an EPA thing, nothing to do with performance.
earlthegoat2
ArboristSite Guru
I'm sorry but I attribute longevity to just plain better. I'm a chainsaw tech so the less I have to work on them because of operational problems the better. Why no love for 2 rings? Granted, I have no verifiable evidence that two rings last longer. I am just responding to Brad 's comment in post 3. I'm still of the opinion that it really does not matter.
