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cycle (Automotive) (OP)
19 Feb 02 21:17
I tried these in a engine I built for racing. Leakdown was excellent,less than 2%.. But, at the time I had no dyno,hence no way to know (other than leakdown) if they were truly beneficial. Was it money wasted or well spent. I normally use a traditional steel alloy/moly top ring , a ferrox coated iron second.Have had very good luck with these also,but always looking for an edge..I am thinking about going with a Total Seal gapless design again,on a mountain motor /nitrous engine. Any experiences out there with these rings?? Street car,race,motorcycle??? Any replies much appreciated........    Craig
Helpful Member!  MaxRaceSoftware (Automotive)
20 Feb 02 2:41
Craig, so far and just in the last month , did i finally
see a "Gapless-Ring Setup" do as good as a normal race ring setup !

i've had a fair number of gapless ring engines on my dyno ,
they look really good on a static leakdown test , but under full load they have a little more blowby CFM than a regular set .

All the engine builders around here who have tried them
in NHRA Stock or Super Stock have told me they slow down with them .    

The only personal-experience with them i had was with a BBC 557 cid when i put the gapless 2nd rings in , the car lost a tenth ...when i put back a new set of Speed Pro plasma moly rings, the car picked up a tenth back to where it was !
What made think it was the rings was

1-it slowed down after , when i thought it should have ran faster

2-just before , thru the MPH-lights , a little smoke top end out of headers ....making me think gas pressure was getting trapped between 2nd gapless ring and top ring, unseating top rings ?????

3-went i went back to SP plasma moly , the ET came back

Never did call Total Seal to see what they thought
but did ask engine builders around here ..they basically told me the same stories of losing ET .

I think they are a very good ring setup for methanol dirt track engines , but not drag racing so far from what i've seen !  
-------------------------------------- saw 2 % leakage on a static leakdown tester

..did you then put the engine full-throttle full-load
on the dyno , and measure CFM blowby ???

if you can , could you test this and post results ??

Larry Meaux (
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers

Helpful Member!  cycle (Automotive) (OP)
20 Feb 02 8:43
Larry,I will gladly post results on engines I dyno. Unfortunately it will be a few months till this one is done.In answer to your engine unseating the top ring , years ago I worked for Jim Ruggles for a short time.He also felt this was a problem.Hence ,He would not advocate the use of gapless rings and of course felt they created more problems than they fixed..So some more questions arise. One, Total Seal has come out with a gapless top ring,this could be a better setup,maybe would alleviate the problem we discussed. Two,on the older 2nd gapless design would gasporting help keep the top ring seated,that is without defeating the purpose.Also remember,my old Progas gapless ring engine had 390 p.s.i. of cranking compression,one would think that the top ring would stay seated . I am going to look into the gapless top ring for the mountain motor. Although so far there are many against this setup. As you stated ,The best setup seems to be the more traditional rings.       Craig
MaxRaceSoftware (Automotive)
20 Feb 02 15:46
, years ago I worked for Jim Ruggles for a short time

Craig, years ago , i think around 1984 to 1986 or so,
Buick gave us a rental car , eats , motel, spending money
to take a trip to Jim Ruggles shop for 2 day question/answer with Ruggles on Buick V6 ...Buick was looking for DragRacer team to run the Buick V6 in NHRA Comp
Elim .   From what i remember he was in the process of moving by the airport there in a new building,
he had 2 dynos setup , but only one working at the time, and a SuperFlow SF-600 ? bench at one end of the shop .

Question - were you working there at that time ???


Larry Meaux (
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers

cycle (Automotive) (OP)
20 Feb 02 18:28
Larry,I worked for Jim after he moved from the airport area to a huge shop in Lithonia Industrial Park,Lithonia,Ga.. Yes we did have the Superflow Flowbench,Superflow Dyno and a second dyno right next to each other.Can"t remember what brand.When I went to work for him apparently Buick had decided to stop racing and go golfing.I remember Jim complaining about this many,many times. We were doing some of Bill Elliots work and some SCCA engines, mostly ITS stuff.I didn"t do engine building for him mostly cylinder head setup. CC"ing ,spring heights,valve machining,etc.Not long after I left to go back to cycles Jim closed shop. Later a customer of mine and a friend of Jim Ruggles told me he had crashed his motorcycle in the Georgia mountains and was hurt pretty bad. I believe he is recovering in California,staying with his son.This all went down around the mid to late 90"s. I know I wish him well, Jim"s a good guy and very ,very "engine smart".I know I learned a few things from him. Thats why I quit motorcycles for a short time, not many oppurtunities to learn alongside engine builders like him.       Craig
Guest (visitor)
21 Feb 02 0:46
wow, gapless rings with nitrous. As you deliver more fuel and oxygen this inturn makes more pressure, thus more pressure on the back of the ring, thus more seal to the wall
thus more friction , heat , and horse power, to ensure even pressure on the ring you need to gas port the piston.
MaxRaceSoftware (Automotive)
21 Feb 02 2:58
any experiences with 2-ring piston Comp or Super Stock engines ?

from what i've seen at the track and on my dyno
with a couple of Super Stock racers with Chevy 350 and Chrysler 360 experimenting with 2 ring -VS- 3 ring pistons,
there wasn't hardly any difference in power .
the 3-ring pistons ran drier and maybe just a little edge over the 2-ring ->(1 comp and 1-oil ring) setup ....
and that was relatively at slower rpm rates and
lower rpm power bands ..where there is more time for leakage and blowby to occur .

the 3-ring SS seems to have one out in SS ??

then you look at some Comp engines that
run from 7500 to 10500 rpm ranges and accelerate
at faster rpm/sec ...with less time for leakage
and the 2-ring pistons work pretty good , although builders still use 3-ring pistons ....they are still pretty close as well !

So if a 2-ring piston works just about as good as a 3 ring piston ...going to a gapless 2nd ring seems not to be worth anything basing it off the 2-ring piston's success

maybe the Gapless "top ring" will finally be worth some HP ??
please post results if you try them...and i'll try and build a dyno test engine to try a set myself .

Larry Meaux (
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers

cycle (Automotive) (OP)
21 Feb 02 8:41
Gary,yes we do use gas porting on certain engines. Larry,A very few companys have (in the past)come out with 2 ring pistons. A couple guys have used them with very good results.While I have no comparitive dyno runs , the 2 ring setup did well on the dragstrip. Ran very "dry" and made good power.R.P.M. range from 9500 to 11,000...    Now for a very interesting story. Years ago I had a very old MTC piston kit in a E.T.Suzuki dragbike. It used the old .059 top ring(now .039).You could call on this bike to run 11.0"s any weekend of the year.Extremely consistent.What I found out was the top rings,all 4 , were shattered on many occasions and subsequent rerings shattered again , yet the bike ran the exact same E.T."s & M.P.H. numbers.It did not seem to matter wether it had a good top ring in it or not.So in answer,in extremely high R.P.M. engines with little time for leakage 2 ring pistons may be an alternative.And worth a little power?? It has been said if the ring friction in a typical 350 Chevy could be reduced to zero an additional 100 H.P. could be gained.An ideal situation coming soon?? A 2 ring piston with the comp ring gapless?? Maybe?? Also would make for a lghter piston. Could be something there..     Craig
Helpful Member!  ivymike (Mechanical)
21 Feb 02 10:37
I think that comment about the rings is a bit exaggerated -

the slider assy (including conrods, etc) accounts for about 33% to 45% of total engine friction. Of this amount, probably about 60% is attributable to the rings (with the piston skirt being the next largest contributor).  So by completely eliminating the rings (without increasing friction elsewhere) you could get rid of a max of about 27% of FMEP.  If FMEP was 1/3 as high as BMEP (and I'm more inclined to say it's 1/8 to 1/10), you'd get a 9% improvement in power by deleting the rings (again, assuming you didn't add friction elsewhere, and that the engine still ran)

Another thing to consider is that if you could give a ring a "frictionless" surface, you'd likely only get rid of 15% to 25% of that ring's friction, as the majority of the power loss is due to pushing oil around.  If you could put a frictionless coating on the ring surface, and then run with the liner completely dry, you'd make a much bigger improvement.

cycle (Automotive) (OP)
21 Feb 02 12:25
Iveymike,It was heresay and I am inclined to agree with you. 100 horsepower sounds like alot to gain from just ring friction.In the quest to "free" up additional horsepower,as in two ring pistons,in the game of drag racing even a tiny amount is important. As you know,races are won by hundreds or even thousands of a second.Friction reduction has become a major player in this field,hence companys like HPC,Swain,etc. I do believe there is something to there friction reduction coatings,but,until I can afford to test these for myself the degree of there benefits remains a true unknown.Despite there claims.I hope in the future I ,and with the information from many others can glean accurate information on friction reduction/anti-friction coatings.If I only had more money!!!      Craig
MaxRaceSoftware (Automotive)
21 Feb 02 20:12
Craig,....just came in today , this week's NHRA's National Dragster with an article on rings and GapLess rings !!
Check it out !!
Remember that these are companies advertizing in ND  :)

Anyways,  interesting to see the efforts they are taking to get the ring surfaces smooth a totally flat on the bottom of piston grooves !!

Sort of what i posted last week or so !!!

i've been ordering pistons from mostly BME since the early 1980's with zero fit or snug fit .043" grooves that forced me to hand lap the bottoms of my Speed Pro rings sets
to get ring surfaces perfectly flat to seal on bottom of grooves ,,,in the process...very tight vertical clearance ,,,but yet extremely free ring rotation where to go , can't float and then use gasport holes to get pressure behind rings to seal !

Been tricking oil ring expanders with a custom set of channel lock pliers i custom ground to fit inside the oil ring gaps ..use a scale and "pull" the oil ring/piston/rod assembly in bore to see lbs.

the Hasting's oil ring seems to control the oil as good as the Speed Pro oil ring, but the Hastings does it with less drag .

Any opinions ??????????

Larry Meaux (
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers

MaxRaceSoftware (Automotive)
21 Feb 02 20:24
Another thing you'll see with too much ring groove -to- ring vertical and back clearances that it will act like an oil reservoir can sometimes sort of "pump oil" ....oil going by rings reduces gasoline octane !!!
in very high CR engines, it hurts HP , or low CR with borderline octane ?

you can sometimes see oil being squeezed out gas port holes
...this effect led me to notice CounterClockwise and Clockwise swirl effects oil trails out of gasport holes in 1975-76 in Chevy SBC ,,,way before i had a swirl meter
..i could see swirl effects ....the old # 492 , #186, # 462 # 461 , and # 292 Chevy Turbo heads back then had tons of swirl :)

Larry Meaux (
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers

cycle (Automotive) (OP)
21 Feb 02 21:07
Interesting,Total Seal does advertise/offer low tension rings.I believe collectively,in a big V-8 , that this may account for a slight increase in power.Not so much for the M/C engines I build. I will say on the subject of ring "oil pumping/collecting" that is a very good possibility. I had a set of very well used forged pistons with well worn ring grooves.Even after a rering the engine still smoked slightly,and after a couple of routine teardowns noticed a film of oil on the domes. At the time it didn"t occur to me that the problem could be the one you described... Another thing,On short lived Pro engines I have noticed (before any runtime) an almost glass like finish on the bore.Friction reduction?? Also,Have you tried a water/block preheat prior to your boring and honing work?? And what do you think of the 2 ring piston with a gapless top ring and a low tension oil control ring???   Tomorrow I will have to check out the latest issue of National Dragster,always curious.... Craig
MaxRaceSoftware (Automotive)
23 Feb 02 17:01
Craig ,   just got through dyno testing a BBC 598 cid engine on the dyno....had a brand new second set of Top Gapless rings , this is in a boat engine !

the 1st set , the boat slowed down to 8.80's from previous 8.60's in quarter mile

after talking to Total Seal , he made rehoned block another new set , came to the dyno....  5 to 8 cfm blowby

Craig, the builder says he finish honing block w/plates to 400 grit , and not too happy with the the Total Seal ring in the 1st position .       When the boat ran 8.60's it had Total Seal 2nd groove rings only with Speed Pro other rings .        Now after today's dyno session,
he thinks he might have gone faster with just a normal set of Speed Pro rings...  so hes coming back to dyno with just Speed Pro rings or normal set of Childs Albert rings to see differences .
Feb 23, 2002
598 Chevy BBC
Dart Tunnel Ram intake
2-Holley stock 1150 cfm carbs w/ 89/89 jets
VP C-16 + C-12 gas Dart 360 alum 2.300/1.880
14:1 CR
Fluid Dampner
Hamburger steel 8 1/4 depth
Castrol 10/40
.026 lash across
Comp Cams roller 280/288  .790/.775
34 deg BTDC
Bowtie Tall-Deck Block
change=38 from 34

  825.7 HP at 6500 RPM
  778.7 TQ at 5200 RPM  600 RPM/SEC

Larry Meaux (
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers

MaxRaceSoftware (Automotive)
23 Feb 02 22:44
Hey Craig ...How's that for Service ?????   :)

you start asking about Total seal Top-Rings
and National Dragster prints an article on this
the very same week !!!  ...and then an engine builder
brings a BBC Chevy to dyno the very same rings
your asking about !!!

i didn't know he had the Total Seal top ring
in the engine till he told me how hard it
was to turn the engine over with his starter .

Without the plugs in, the engine was a free as any
other engine .

we put my Tilton Super Starter on the engine,
and it handeled the cranking back to almost normal .

Larry Meaux (
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers

cycle (Automotive) (OP)
24 Feb 02 2:31
You know,You would think that this would be the ideal setup. Apparently, not so!! I guess it"s easy to convince myself that a gapless ring is ideal when in fact a high qaulity conventional ring is proving itself to be the very best setup.As much as I hate to say it, I believe for now ,I will have to stay with traditional rings. Much Thanks Larry for the info.What else can be said?!?!  I really have to wonder(besides top ring unloading) what is really going on here. It is hard to believe these rings are costing so much power. I will be the first to admit I am at a loss to explain this problem. I"ll have to give this some thought.. Seems strange to that they can keep putting out a product,that for the most part, is not working to well.....   Thanks Again......   Craig
MaxRaceSoftware (Automotive)
24 Feb 02 4:39
Seems strange to that they can keep putting out a product,that for the most part, is not working to well.....   Thanks Again......   Craig

Craig , what you just posted is exactly my same thoughts !!!

i also find it very strange/perplexing at why the Total Seal Gapless ring setup in either the 2nd or Top groove would not be miles ahead BETTER than anything else out there !!!!!   i'm definetly going to start researching this

on paper looks GREAT !!!
but about the BEST results i seen so far is they are
at best no better than conventional rings .

i'll have to start calling people i know and learning more on this whats going on !!

will post some info if its worthy later on .

Larry Meaux (
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers

MaxRaceSoftware (Automotive)
27 Feb 02 13:06
On the subject of rings ;

i file-fit the Compression Rings' gaps ,
but i only file one side (usually side with dot)
leaving the other side bone-stock with its dark coating i'm file-fitting, i then use the unfiled side
to "square" up against to make sure i'm filing the other side parallel ....and if you want to experiment with seeing how much gap you can run with a certain HP-output with a ring a certain distance down can view each gap side
with a 10x lighted-viewer and look for signs of ring butting
which will show up easily on the unfiled side..this is all after you've actually ran the engine under full load and then have taken it apart for study.

also you should very lightly deburr the side you filed
and the other side with a small handheld the kind you would use to sharpen a pocket knife ...
deburring gap edges reduce cylinder wall scratches

Larry Meaux (
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers

evelrod (Automotive)
28 Feb 02 11:07
Larry, here is one for you, My highest hp and best performing engine on the track (TWO lap records, one in Texas and the other in California) had out of spec ring gaps . Almost .010 too wide in a 3.290 bore???????????

We didn't find this out until after the engine was pulled down for a rebuild some 100 hours later!!!  The completed bottom end would turn over at 11 inch/lbs.

Sometimes I just  wonder about the effort I  go   to in building the  'perfect' engine when I run into an anomoly such as this.

MaxRaceSoftware (Automotive)
1 Mar 02 0:43
Sometimes I just  wonder about the effort I  go   to in building the  'perfect' engine when I run into an anomoly such as this.---Rod


Rod, you still have to keep on will pay off in the long run !!! don't "see" all the other times things would have really gone bad if you wouldn't have taken the time to do them right !  its harder to fail a part if you assemble it correctly.

Larry Meaux (
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers

sbc (Automotive)
3 Mar 02 11:02
I've tried gapless rings too, with the same results
as posted here. Great cranking pressure & great on
a leak down test, but more blowby under operation.
I believe this is because air behind the ring needs
to breathe, especialy with tight groove clearances.
I've stoped gaping rings to the minimum, and found
some power there!
evelrod (Automotive)
3 Mar 02 13:03
sbc---I put the Mini back together with factory spec ring gap. NO extra effort on my part. I, like you, found equal or better perceived performance from the subsequent twincams using a bit wider gaps as  supplied by Deves. (That record setting 1984 engine destroyed itself when the block cracked between the core plugs and I spun in the water, got it on video , though.)    

slowkaw (Computer)
4 Mar 02 21:32
This stuff really starts to make me think I don't know anything.  Cycle and I just tore down my 1075cc Kawasaki, and found the piston-to-cylinder wall at .065" and ring end gap at .019".  This engine took me to a 9.61 e.t.@136+mph run while driving through the clutch slightly.  This weekend, I bored and honed another cyl. block at .015" and file-fit new rings @.012".  The worst leakdown with the old set-up was 4%.  After looking at the old rings under a lit magnifing glass, only the edges of the rings were shiny where there was contact with the cylinder wall.  I'm hoping for some improvement and will let you all know if you like.  After reading some of the previous posts, I am starting to wonder if all the effort is worth it in the long run.  Any opinions?

MaxRaceSoftware (Automotive)
4 Mar 02 23:54
i guess i'm sort of from the "old-school" ..that is
i like to see static leakage at below 6 percent on
the engine stand and   2 to 4.5 CFM on the Blowby
..kind of like to have it both ways !!!

since NOS has made a big-impact on racing in last decade
i'm seeing racers coming to dyno with .025" to .027" ring end gaps and still getting 4 to 6 CFM Blowby levels

gaps that are .025" to .027" don't give you great "STATIC" leakdown numbers , but seem to be OK under full load , acceleration dyno testing, enough to get you 4 to
6 CFM blowby if the rest of the parts (Block,Pistons,etc)
are machined/assembled correctly

Larry Meaux (
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers

slowkaw (Computer)
7 Mar 02 22:07
I made a big mistake when typing my clearance figures on my last post.  I meant to say .0065" piston-to-cyl. clearance.

MaxRaceSoftware (Automotive)
8 Mar 02 11:39
Hey David ,...i knew you meant .0065" , and probably everyone else here too  !   :)

my typing isn't so great either ?

Larry Meaux (
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers

cycle (Automotive) (OP)
8 Mar 02 13:11
Something David failed to mention,Typical piston to wall clearance on forged pistons for us is .001 to .0015.. Ring end gap for his diameter piston/application is .008 to max .010.. You see his clearances were way big,yet this engine did not smoke,held leakdown to max of 4%!!Engine performed extremely well for it"s size and condition.  His fear is that with a fresh bore in and fresh rings performance will actually diminish?? (I have seen stranger things happen.) A few more weeks of build time will tell.. ...   Craig
ShaunT (Automotive)
21 Apr 03 15:44
I have had all of the ring sealing problems go away once I started final honing with a 280 grit and then brushing it 10 strokes, rather than using the traditional 400 grit and no brush. If you check the finish with a profilometer, you get about 15RAwith a 280 and about 6RA with a 400. The 15RA is what the ring manufacturers want today. You will see instant ring seating and they will last longer.

Shaun Tiede ULTRADYNE Arlington,TX

EngJW (Mechanical)
21 Apr 03 17:24
In reference to the comments on ring unseating, I have heard some opinions (and seen at least one SAE paper) that claim the 2nd ring should have a larger gap than the top ring. The reason is to allow any trapped gas to escape through the 2nd ring gap in order to prevent unseating the top ring. It is a matter of the relationship of the pressure below the top ring to the pressure above it, and this varies throughout the cycle.

John Woodward
evelrod (Automotive)
21 Apr 03 18:27
This is a very old thread but since your a new member Shaun, I'll post to it again.  I like what you have to say about camshaft design, in general but, my work is with DOHC and small I4 SI engines  for sport car and vintage racing so some of the Chevy stuff is a little out in left field for me. I had Ron Isky do all my profilling successfully several years back (sometimes I got some wierd comments about what I am running them in).  At any rate your welcome here and I hope you will continue to grace us with your expertise in cams.
No matter---to the point of "gapless 2nd rings".  As stated last year(posts above)---don't like them.  They cause problems with flutter that NEVER existed and lots of blowby at certain rpm.  I went back to my old Deves with their wide gaps and all was ok once again.  If they work for you, great but, I did not like the results I got.


ShaunT (Automotive)
22 Apr 03 9:25
EVELROD: Thanks for the extended invotation. I can design swing and follower cams, but the tooling to manufacture them is totally different from push rod cams. Hence I do not produce any. Is there anything I can do to get you out of left field on this cam lingo stuff?

Shaun Tiede

Shaun TiedeULTRADYNE Arl,TX(

evelrod (Automotive)
22 Apr 03 12:35
Yeah Shaun.  Make me 23 again.  That's when I raced an NHRA record class 283 SBC in Amarillo(Jack Moss Automotive).

I'll leave the V8 stuff to y'all and I'll stick to the DOHC and little four bangers.  Their fast enough for me.


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