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steelcomp was here
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Discussion Starter #1
So I've always wondered...what's the difference between a standard tension ring with no gas ports, and a low tension ring that's in a ported piston? In a static condition, the low tension rings shine, with far less drag, but I've always wondered in a dynamic condition, do they actually have less drag?
 

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Bostick Racing Engines
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So I've always wondered...what's the difference between a standard tension ring with no gas ports, and a low tension ring that's in a ported piston? In a static condition, the low tension rings shine, with far less drag, but I've always wondered in a dynamic condition, do they actually have less drag?
Ported pistons only deal with the increased radial tension on the top piston ring.

The only issue I have delt with is oil control problems associated with low tension oil rings. The nearest I could figure is that without the aid of some sort of vacuum on the crankcase the low tension ring didn't control oil as well and had some consumption/vapor issues. I tried both std and low tension oil rings and the hp result was the same on the dyno and in the application (off-road endurance type dealy-o) Also it didn't seem to matter whether it as a big dog 427 LS or 3.5 Honda V6 (both asperated and supercharged)... they were stinky out the breather and drank a little oil. Even tried a different ring package but retain the low tension (went from .062 .062 .187 to 1.2mm 1.5mm 3.0mm with a napier 2nd to try to help control the oil). Then went back to std tension which, with no other change (even honed the block the same and retained the same ring end gaps) made very much an improvement. In my opinion... on the dyno (chassis dyno for what it matters) it wasn't worth the effort. I'd say drag race... and/or with dry sump or vacuum pump (anything that pulls vacuum) then low tension is cool... otherwise std.

I haven't tried the same back to back same engine tests on marine applications, but I would imagine that it would be somewhat simmular to that of the off road race applications... mid to upper rpm for extended periods and lots of throttle jockying in less than ideal operating conditions.

I'm sure there are folks that have vast more knowledge in this area and say I'm out of my gord... but from what I've seen in the real world... not strictly what is observed on dyno sheets... this is my experience.
 

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steelcomp was here
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Discussion Starter #3 (Edited)
Mainly referring to top ring. Thanks for the input.
My thought was that maybe since the ported piston/ring was only seeing pressure during combustion (and high cyl presure), that during the rest of the piston's travel there might be less friction and that might have some nano-benefit..
 

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Resident Ford Nut
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BITE ME

my understanding is that they really only show a gain due to the reduced drag on the intake stroke.
For what it's worth I have the opportunity to talk to the guys from CP pistons at the track on Saturday. Crower had told me that's who he wants to order my new set of pistons from next year. Crower had suggested a replacing my "old" zero gap second ring with a medium tension ring with gas ported pistons. I think I was talking to Mike from CP and he liked that idea.

If I recall correctly the medium tension rings reduce ring drag by several pounds ( I want to type a number ,but I don't want to be way off on it) In any-case I would think that reduced friction would help every time the pistons is moving up or down ? :)bulb :)bulb

Sleeper CP
Big Inch Ford lover :D
 

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I think the reason they aren't that beneficial on the other strokes is because the ring is still pressure loaded on the exhaust, compression, and power strokes. Like Steel asked, how much do they help in a running engine compared to pulling them thru the cyl;inder with a fish scale? I remember when "L", *****, Head land rings were all the rage in two strokes. They would taper the hell out of the cylinder over time because they had almost no wall loading at the bottom and a ton at the top, on every trip. As far as zero gap rings, 1st or 2nd, I don't get them, never have, but that's just an OPINION:D



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steelcomp was here
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Discussion Starter #8
So what about a ported piston/top ring on the intake stroke? If the ring has increased tension with pos. cyl pressure, would it work in the reverse on the intake stroke, where there may be negative pressure in the cyl? Would it have even less tension, and if so, what happens when you add some pos. crankcase pressure to that?
 

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Cantard
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Your on the right page Steel..unless your running a vac pump there will allways be crank case pressure...just some more than others which gets right back full circle to the rings.....btw what is so important about a second ring anyways.;) On a gapless ring what purpose does it serve? Wouldnt one good ring be better than two low tension rings? ....cylinder drag....rotating mass exc.?
 

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Your on the right page Steel..unless your running a vac pump there will allways be crank case pressure...just some more than others which gets right back full circle to the rings.....btw what is so important about a second ring anyways.;) On a gapless ring what purpose does it serve? Wouldnt one good ring be better than two low tension rings? ....cylinder drag....rotating mass exc.?

About 10 years ago at the dirt track near me there was a guy winning almost every race in the street stock class. Pretty much everyone ran a 350 SBC with a specific Holley 2 bbl carb, untouched intake and heads, flat tappet cam and flat top pistons. Stock-stock-stock

This guy had more HP than anyone else and you could hear him RPM past everyone else on the track. The motor was not a $25,000 super slick 2 bbl deal just a back yard motor. He constantly got torn down but always passed. Strong rumor was that he only ran a top ring and oil rings, no second ring.

Jim
 

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Cantard
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About 10 years ago at the dirt track near me there was a guy winning almost every race in the street stock class. Pretty much everyone ran a 350 SBC with a specific Holley 2 bbl carb, untouched intake and heads, flat tappet cam and flat top pistons. Stock-stock-stock

This guy had more HP than anyone else and you could hear him RPM past everyone else on the track. The motor was not a $25,000 super slick 2 bbl deal just a back yard motor. He constantly got torn down but always passed. Strong rumor was that he only ran a top ring and oil rings, no second ring.

Jim
shoooosh!!!!!:D
 

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steelcomp was here
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Discussion Starter #12
shoooosh!!!!!:D
;)
My guess is the second ring is an attempt to help reduce crankcase contamination, but we've since learned that allowing a little blow by to get past the second ring only helps reduce top ring flutter. If the top ring is doing it's job, the second ring seems redundant. Everything I worked on as a kid (with two wheels) had only a top ring, and two cycles, not four. Seems that ring was doing double duty compared to a four stroke. I know...a little apples and oranges, but the point still remains...
 

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aren't the nascar boy's running two rings ?

on the street stock guy.. are they running alcohol ?
or pump gas ?
...alcohol is mixed with castor bean oil ? similar to a two stroke ?
two strokes run two rings.. some run only one..

so, gas port the top ring.... run a good oil control ring .. and a little prope oxide... or some mtbe...and great cam timming......43 deg...and walla..
out in front you go..

LOL !
sounds good on paper..
 

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Cantard
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or you could gas port the oil ring.....not the top single ring....pull the ring tight on the way down...less drag on the way up....

What is your feeling on this Steel?:)bulb
 

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steelcomp was here
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Discussion Starter #15
or you could gas port the oil ring.....not the top single ring....pull the ring tight on the way down...less drag on the way up....

What is your feeling on this Steel?:)bulb
Not sure how you'd gas port the oil ring(S)...something I'm missing here? They'r just basically scrapers anyway, aren't they? (I hope you're not messing with me Hallet...:|err):D
 

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steelcomp was here
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Discussion Starter #17
aren't the nascar boy's running two rings ?

on the street stock guy.. are they running alcohol ?
or pump gas ?
...alcohol is mixed with castor bean oil ? similar to a two stroke ?
two strokes run two rings.. some run only one..

so, gas port the top ring.... run a good oil control ring .. and a little prope oxide... or some mtbe...and great cam timming......43 deg...and walla..
out in front you go..

LOL !
sounds good on paper..
Are they?:)bulb
 

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sweet..
thin top land..

side to side located off the pin boss underneath ?
 
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