Grinding the rings

[spuldup]

I saw on YT Ironhorse did a mod to convert a "high tension" ring to a "low tension" ring. I have not heard of this before. He also removed the bottom ring of a 2 ring saw. These are to reduce friction, of course.

It's the second half of this video.

Any of you out there ever tried this and have a before/after comparison? I'm thinking that it may work at first, but fail sooner than the 2 stock rings. Just looking for any personal experiences, not opinions on IH, thanks.

 

[wildwes]

What would be the benefit sought by doing anything to reduce ring seal? To my way of thinking either of these mods would reduce ring seal, therefore reducing compression, leading to power loss. I also don't proclaim to be an engine expert, so maybe I'm missing something.

 

[Sidecarflip]

On conventional 4 stroke engines you always check and if necessary adjust (grind) the end gap but then 4 strokes have multiple rings.

 

[wildwes]

On conventional 4 stroke engines you always check and if necessary adjust (grind) the end gap but then 4 strokes have multiple rings.

Yep, they are ground if needed to provide clearance and prevent binding, but it sounds like he is asking about grinding on them to reduce ring tension/pressure?

 

[spuldup]

What would be the benefit sought by doing anything to reduce ring seal? To my way of thinking either of these mods would reduce ring seal, therefore reducing compression, leading to power loss. I also don't proclaim to be an engine expert, so maybe I'm missing something.

Agreed. There is no objective evidence to his claim of less frictional loss. But IH is saying subtextually that the rings are too wide. Last half of the video is 15minutes long but you can skip most of the grinding.

 

[spuldup]

On conventional 4 stroke engines you always check and if necessary adjust (grind) the end gap but then 4 strokes have multiple rings.

This is referring to grinding the inner circumference of the ring (by -.020" to -030) to lessen the tension from ring to cylinder.

 

[sean donato]

It's a stupid idea at best and at worst it destroys a top end. The rings won't last nearly as long to begin with and the lack of tension will undoubtedly lead to premature sealing issues. People need to stop using 4 stroke philosophy on 2 strokes. They arnt great in a 4 stroke when you get down to it either.

 

[northmanlogging]

I saw on YT Ironhorse did a mod to convert a "high tension" ring to a "low tension" ring. I have not heard of this before. He also removed the bottom ring of a 2 ring saw. These are to reduce friction, of course.

It's the second half of this video.

Any of you out there ever tried this and have a before/after comparison? I'm thinking that it may work at first, but fail sooner than the 2 stock rings. Just looking for any personal experiences, not opinions on IH, thanks.

Ok... ok... no no...
So this is the type of old grey beard sage that needs to find a pasture to unalive in... bunch of wise sounding stories that puff himself up more then he should be to impress on the young "bucks" that he's been there and done that... yeah ok.
Removing a ring, is tried and "true" race saw stuff, whether it does any good? I have my doubts. But they do seem to run afterwards so?

grinding on rings to make them have less "tension" is capt. dumbass territory, not only does it cause potential weak spots in the ring from uneven grinding, but also, HEAT will naturally cause the rings to get a little less sproing, and that extra .020" of material is pretty damned important in keeping that ring from coming apart under load, and heat, to say nothing about the lifetime of wear, (honestly I've never seen a saw with a worn out P+C, I'm sure they are out there, but generally the crank wears out or they get an air leak and lean out and die first)

To say nothing of capt ding-a-ling filing the top of the piston off? for? better Transfer port timing? (couple this with losing a ring that saw would be lucky to have any compression left)

Dude goes on a tirade about lightening the piston, grinding away features that are there for strength, cutting off the skirt, the does a helluva lot more then just guide it in the bore, the skirt is essentially the valve between the intake, and exhaust ports, so be careful messing with those...

Besides if you reallllllllllly are concerned about lightening the rotating assembly, pull the crank and grind off some big ole slabs of counter weight (which also, if your lightening the piston, you should probably also lighten the crank counterweights... its uh... sort of important for you know vibration and stuff)

 

[wildwes]

and that extra .020" of material is pretty damned important i

Definitely. I know in a 4 cycle around 1-2 thousandths is the target for ring side clearance and as the number grows, compression rapidly drops. It doesn't take many thousandths to make a big difference in compression, and subsequently a loss in performance.

 

[northmanlogging]

Definitely. I know in a 4 cycle around 1-2 thousandths is the target for ring side clearance and as the number grows, compression rapidly drops. It doesn't take many thousandths to make a big difference in compression, and subsequently a loss in performance.

I got to rambling, not only does it weaken the ring, the depth of the groove its supposed to fill has as much or more to do with it "sealing" then the actual contact with the cylinder wall, gasses will find the easiest way through, for most rings thats the gap at the end, which is why there is sometimes a second (or more) compression ring, the clearance between the width of the ring, and the groove, as well as the depth of the groove are all designed to dance together to create as tight of a seal as physically possible, mess with any one of those features you mess with potential compression

 

[northmanlogging]

Besides... piston rings are fairly easy to make if you have a lathe and some cast iron, then you can make all the custom rings you like with whatever tension you think is skookum, though I find it hard to believe that the factories haven't got that dialed in... 200 years or so of piston driven engines and mechanical tinkering, somebody somewhere might have figured out the secret sauce, patented it, and sold it to the folks that make engines go vroooooom

 

[Backyard Lumberjack]

I saw on YT Ironhorse did a mod to convert a "high tension" ring to a "low tension" ring. I have not heard of this before. He also removed the bottom ring of a 2 ring saw. These are to reduce friction, of course.It's the second half of this video.
Any of you out there ever tried this and have a before/after comparison? I'm thinking that it may work at first, but fail sooner than the 2 stock rings. Just looking for any personal experiences, not opinions on IH, thanks.

'no comment!'

 

[NSEric]

I'll try most any mod I can in a cheap saw to get more power out of it but im not grinding on the rings or taking one out.
The rings support the piston and hold it straight on the bore, worn or ground down rings will let the piston rock in the bore and wear the skirt out. Same as removing the bottom ring, single ring pistons have a beefy thick ring to support the piston, 2 ring pistons have thin rings, one thin ring wont support the piston very well. One thin ring would be ok in a race saw that only goes through a tank a gas a year but not in a work saw, you'd need a new piston pretty quickly.
Old harv tries real hard to sound like a super smart engine builder that knows tricks other builders dont. If he doesnt know how to make a saw better he does crap like this and tells people it's faster.

 

[thompsoncustom]

Ya that guy is terrible don't watch his videos. Is there things that can be done to the piston/ring to increase power or rpm? yes of course but that's not one of them.

Haven't seen it done in chainsaws but increasing ring seal by gas porting the piston increases power and is commonly done in race engines.

 

[Sidecarflip]

Besides... piston rings are fairly easy to make if you have a lathe and some cast iron, then you can make all the custom rings you like with whatever tension you think is skookum, though I find it hard to believe that the factories haven't got that dialed in... 200 years or so of piston driven engines and mechanical tinkering, somebody somewhere might have figured out the secret sauce, patented it, and sold it to the folks that make engines go vroooooom

I'd really like to see you or anyone else do that. I do own a short run machine and fab shop so please explain to me the exact procedure as I'm all ears. Piston rings aren't produced from CI anyway. they are produced from alloy steel and heat treated accordingly. Finally, the end gap on a piston ring on a multiple ringed piston (4 stroke engine) is always predicated by the manufacturer of the piston / ring assembly. Not sure about a 2 stroke however.

 

[northmanlogging]

I'd really like to see you or anyone else do that. I do own a short run machine and fab shop so please explain to me the exact procedure as I'm all ears. Piston rings aren't produced from CI anyway. they are produced from alloy steel and heat treated accordingly. Finally, the end gap on a piston ring on a multiple ringed piston (4 stroke engine) is always predicated by the manufacturer of the piston / ring assembly. Not sure about a 2 stroke however.

There's plenty more

 

[northmanlogging]

Granted that is a massive ring, but dude does show a smaller 2 stroke ring in the beginning of the vid.

Keep in mind I was a machinist for 25 years, and before starting my logging company, I had considered starting a machine shop, I have the experience and the connections to probably even make a go at it, however there are alll sorts of things I've never done in a machine shop, doesn't mean they don't exist, or that they are impossible, I just didn't see it happen.

 

[Sidecarflip]

There's plenty more

If it's on YT, it's most likely BS anyway. I watch YT for entertainment purposes only. I have my Journeyman's card in tool and die making and I'm a certified TIG welder as well. You don't make piston rings from cast iron. Maybe that clown does but not this clown.

 

[Sidecarflip]

So, you were a grunt machine operator I take it. Not gonna argue with you, I know what I know and I'll leave it at that.

 

[64poncho]

Besides... piston rings are fairly easy to make if you have a lathe and some cast iron, then you can make all the custom rings you like with whatever tension you think is skookum, though I find it hard to believe that the factories haven't got that dialed in... 200 years or so of piston driven engines and mechanical tinkering, somebody somewhere might have figured out the secret sauce, patented it, and sold it to the folks that make engines go vroooooom

I tried it once. For an experiment, made rings for my David Bradley, with a worn cylinder. Had a piece of cast iron round stock we use at the shop to sleeve bearing bores in castings. They did work, briefly! Saw ran one time. Couldn’t get it started after that. A tear down inspection, found that all the tension was gone from the rings.
Began searching how to make piston rings. I learned that the rings need to be heat treated to maintain their shape. Because the cylinder was not usable anyway, it was replaced with a good used cylinder and NOS rings.