dual ring vs. single ring pistons

[Joe Kidd]

so your saying that it dose not help with keeping higher compression

Correct. Two ring is a EPA insurance policy. Only 10 fewer carbon molecules discharged with a two ring setup. LOL

 

[Rokon]

ROFLAO!

Love the ending...

 

[bucknfeller]

It's definitely harder to clean up a cylinder that's been strait gassed on a 2 ring setup. For whatever reason they seem to make more mess on the exhaust side and also there is usually two nice long scores in line with the ring gaps on the intake side. Most of the single ring strait gas victims I've seen, the intake side has been pretty clean.

 

[Joe Kidd]

It's definitely harder to clean up a cylinder that's been strait gassed on a 2 ring setup. For whatever reason they seem to make more mess on the exhaust side and also there is usually two nice long scores in line with the ring gaps on the intake side. Most of the single ring strait gas victims I've seen, the intake side has been pretty clean.

More steel=more smear I guess.

 

[2strokenut]

id like to know some read outs of a compression test on a single ring and duble ring setup

 

[Jacob J.]

It's definitely harder to clean up a cylinder that's been strait gassed on a 2 ring setup. For whatever reason they seem to make more mess on the exhaust side and also there is usually two nice long scores in line with the ring gaps on the intake side. Most of the single ring strait gas victims I've seen, the intake side has been pretty clean.

I've seen single-ring saws like 272s smear just about the entire top of the piston onto the cylinder walls. It all depends on how long the operator runs it with the compromised condition.

More steel=more smear I guess.

Piston residue is usually what you see on the cylinder wall, not ring residue. Pistons are an alloy as you know, silicon/tin/aluminum/other trace elements. I've seen pistons with a higher silicon content smear less material onto the cylinder wall in a lean or straight gas condition but they're more likely to damage the plating as well.

My question is, anytime one of these threads pops up, someone says "Oh yah, it's EPA stuff." Then why was Stihl putting two-ring pistons in their saws 20 years before the EPA even existed? Why did Mall put three and four ring pistons in their saws starting in the mid-30's? Why did Homelite put three-ring pistons in the 26LCS, 7-29, and 8-29? How come the Contra, Contra Lightning, Contra Super, and 090 have always had two-ring pistons?

 

[Joe Kidd]

I've seen single-ring saws like 272s smear just about the entire top of the piston onto the cylinder walls. It all depends on how long the operator runs it with the compromised condition.



Piston residue is usually what you see on the cylinder wall, not ring residue. Pistons are an alloy as you know, silicon/tin/aluminum/other trace elements. I've seen pistons with a higher silicon content smear less material onto the cylinder wall in a lean or straight gas condition but they're more likely to damage the plating as well.

My question is, anytime one of these threads pops up, someone says "Oh yah, it's EPA stuff." Then why was Stihl putting two-ring pistons in their saws 20 years before the EPA even existed? Why did Mall put three and four ring pistons in their saws starting in the mid-30's? Why did Homelite put three-ring pistons in the 26LCS, 7-29, and 8-29? How come the Contra, Contra Lightning, Contra Super, and 090 have always had two-ring pistons?

Understood. My point was two rings possibly having the ability to smear more piston residue around because of the dual surfaces.

 

[Joe Kidd]

Correct. Two ring is a EPA insurance policy. Only 10 fewer carbon molecules discharged with a two ring setup. LOL

Key word here. LOL A funny

 

[bucknfeller]

I've seen single-ring saws like 272s smear just about the entire top of the piston onto the cylinder walls. It all depends on how long the operator runs it with the compromised condition.

Not trying to be a smart :censored: in any way, but most strait gas victims I've seen ran until they stopped themselves.

 

[Jacob J.]

Key word here. LOL A funny

I'm with you, but like I said, it's always the canned answer.

Not trying to be a smart :censored: in any way, but most strait gas victims I've seen ran until they stopped themselves.

Sometimes. A lot of the customers I dealt with at the shop would catch themselves before the engine was absolutely seized. Even among the many hundreds of straight gas victims I've bought, they usually aren't seized. I recently cleaned up an agency saw, Husky 353, with the worst transfer I've seen in my life. It cleaned up though, with about 5 hours of elbow grease.

 

[1Alpha1]

One ringers are easier to start

I see that it's gonna take me a while to live all that down.

Didn't starting that 046 I had mean anything? :hmm3grin2orange:

 

[TK]

I had to take the bottom ring out to let off some compression, it was getting to the point where I couldn't pull the rope no more. She dropped a lot, glad I did it.

 

[blsnelling]

I've tested a saw with and without the bottom ring and it makes almost no difference at all. I'm taking maybe 5 psi or less. I just built a 460. It had a simple .035" popup piston, a single new ring, and still made 212 psi on a SnapOn gauge.

 

[2strokenut]

I've tested a saw with and without the bottom ring and it makes almost no difference at all. I'm taking maybe 5 psi or less. I just built a 460. It had a simple .035" popup piston, a single new ring, and still made 212 psi on a SnapOn gauge.

thank you just what I was wanting to know

 

[Justsaws]

So here it is. Dual ring vs. single ring vs. dual ring running one ring. Name your poison and why.

I prefer single rings. If I have a choice I'll take a dual ring and run the upper as it tends to be thinner than a standard single ring piston. What does that stupid 2nd ring do anyway?

If 2 are present which wears faster?

Where does it wear the fastest?

Where does worn piston ring material go?

Why are the 2 ring locators not in the same postion?

Partner ran singles in chainsaws and doubles in cutoff saws, why?

What brands currently run singles in premuim priced "pro" saws?

 

[sachsmo]

If 2 are present which wears faster?

Where does it wear the fastest?

Where does worn piston ring material go?

Why are the 2 ring locators not in the same postion?

Partner ran singles in chainsaws and doubles in cutoff saws, why?

What brands currently run singles in premuim priced "pro" saws?

Me thinks Husqvarnas use a lot of singles Dolmar does too.

As far as the cut-offs go, them dudes take abuse to a whole new level.

Got one that the skirt on intake side was worn paper thin, it still ran.

 

[casual cutter]

I've worked construction, and I've never seen any small gasoline powered tool take as much abuse as a cut-off saw. From how they are treated, to the extremely dusty and dirty environment they are operated in, to whom mixes the fuel, to the various people that will run 'em during the course of a shift and not care. They aren't run all day, but when they are...

 

[Slamm]

I've tested a saw with and without the bottom ring and it makes almost no difference at all. I'm taking maybe 5 psi or less. I just built a 460. It had a simple .035" popup piston, a single new ring, and still made 212 psi on a SnapOn gauge.

I'm guessing that was on a newer ring/piston cylinder replacement deal. If its 5psi when new, wouldn't it lead one to believe that when the saw has many years of use on it, that the difference would be higher, and therefore if there is just maybe a minor speed difference when cookie cutting lets say 1 second faster, the two ring setup would delay potential for a re-ring for sometime, possibly years?

Sam

 

[sachsmo]

I'm guessing that was on a newer ring/piston cylinder replacement deal. If its 5psi when new, wouldn't it lead one to believe that when the saw has many years of use on it, that the difference would be higher, and therefore if there is just maybe a minor speed difference when cookie cutting lets say 1 second faster, the two ring setup would delay potential for a re-ring for sometime, possibly years?

Sam

Rings are consumables, the trick that enables them to seal is the combustion pressure behind the ring. Looking at it that way, the bottom ring will never seal as well as the top.

When putting in new ring(s) get the saw into some wood right away. Run her like you stole it under load of course.

 

[RandyMac]

You are all full of crap. You gotta have three rings.

:hmm3grin2orange: