RES
ArboristSite Operative
Are there any new Stihl or Husky saws that only have one ring on the piston? Is this a way to tell a homeowner saw from a Pro saw? As I remember the 020AV had two rings whereas the 015 had only one.
Single Ring Pistons
- Thread starter RES
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SawTroll
Information Collector
I am certainly no expert, but as far as I have been informed, the Husky 372xp still has a single ring one over here. In the US they have a double ring piston.
It is definately not a way to distinguish pro saws from homeowner ones - it is more a matter of "taste" as it is debatable what is really the best solution.
It is definately not a way to distinguish pro saws from homeowner ones - it is more a matter of "taste" as it is debatable what is really the best solution.
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timberwolf
Addicted to ArboristSite
Many race engines use a single ring design, the second ring is just drag, and the pressure trapped between the rings can work to unseat the top ring.
Second ring might help with heat transfer. Also might help low speed compression, but that makes little difference above 8k where a saw cuts.
Second ring might help with heat transfer. Also might help low speed compression, but that makes little difference above 8k where a saw cuts.
Lakeside53
Stihl Wrenching
All current models of Stihl saws have two rings. The last to use a single ring was the 009 about 10 years ago, then they went to two rings even on that saw. Prior to that, the old version of the 024 was the other "later" Stihl to use a single ring.
For current saws Stihl uses 2 x 1.2mm rings. Earlier designs used 1.5mm. Most blowers are 1.5mm.
Racers use one ring to redce friction, but they don't care about longevity.
For current saws Stihl uses 2 x 1.2mm rings. Earlier designs used 1.5mm. Most blowers are 1.5mm.
Racers use one ring to redce friction, but they don't care about longevity.
RES
ArboristSite Operative
What about the Husky's and Jonsereds? Are they all single ring design?
Freakingstang
Doctor Freakinstein
From what I have found, most all of the 372's here in the US are double ring. The first year 372 and a few 371xp's had a single ring, but after that everything has been double ring. Most of the smaller huskies are single ring (350, 345, 55 rancher, 50 etc. I have seen 365's both ways.
I'm not too sure on the brand new huskies
(570, 575, 455 Rancher,etc) Maybe some of the porters can tell you the mid sized saws 353, 357, 359
I'm not too sure on the brand new huskies
(570, 575, 455 Rancher,etc) Maybe some of the porters can tell you the mid sized saws 353, 357, 359
SawTroll
Information Collector
As far as I know, the last 371s had double rings in the US, and all the 372s - but I may of course be wrong.Freakingstang said:
Like I said, they still have a single ring here.
Single or double rings are more about what the markets want than anything else I think.
timberwolf
Addicted to ArboristSite
It's a perception thing, two must be better than one.
Maybe near the end of a rings life the second ring picks up when the top one starts to fail.
Maybe near the end of a rings life the second ring picks up when the top one starts to fail.
Lakeside53
Stihl Wrenching
SawTroll said:Single or double rings are more about what the markets want than anything else I think.
I don't think the "market" has a clue about what they want in terms of number of piston rings... but what they want is life..
Stihl ,husky and others aren't battling each other over numbers of rings, so I'm sure here are valid reasons for using the 2 ring approach.
My limited understanding is that two rings last longer than one and transfer heat better, aiding life time..
timberwolf
Addicted to ArboristSite
To quote the original question,
I would say this question is a good indication of the market, easy to make a mental link that a ring cost money, so the manufacture is dropping to one ring on non pro saws to save money and if two rings are better than one three must be better yet...
I would say this question is a good indication of the market, easy to make a mental link that a ring cost money, so the manufacture is dropping to one ring on non pro saws to save money and if two rings are better than one three must be better yet...
The 346 and all small Huskys use one ring, the 357/9 as well, i think. my old 346 has had a lot of use and still runs like a champ. One ring might allow quicker acceleration due to the decreased friction. I'm not a tech, but would dare to guess that a one ring saw might not wear the jug and piston quicker, just the ring.
RES
ArboristSite Operative
I would think that the second ring would be needed to prevent compression leakage at the ends of the ring. They always tell you not to line up the slots.
Freakingstang
Doctor Freakinstein
RES said:
I've got a single ring 372 that has about 180 pounds of compression....Might not last as long as two thinner rings, but it runs better than a stock 372
Saw Troll, the single ring piston was used in the 371's, you are correct the last few years had the double. From what I have found, the 2171 Jred was available up until fairly recently (2-3 years) with a single ring piston. I went on a buying spree buying up all the single ring 372 pistons I could find. I don't actually know if they came in 372's, as everything has been EPA over here. Funny, though, the 365 is more common with the single ring from what I've seen.
Steve
rickyrooster
ArboristSite Guru
ive got a jonsered 630 super which had a two ring piston in it. i thought it came with a single ring piston. the replacement i put in it was also a two ring piston but the rings were thicker than the one i removed. im not sure which setup is best but ive always thought two rings seam better the just one.
rick!
rick!
