I am thinking about using the gapless second rings in my rebuild. I have no experience with them and am just trying to get a feel for them. There seems to be a lot of people for and against them. I understand the principle behind them and they seem to offer a lot for an engine that will see long life, but has anybody got any real life experience with them that they would like to share. I know they are a little bit more expensive than std. rings, but that is not the issue here. How about oil control ? PCV operation, longevity, etc..... Anyone? :rolleyes:

 

I've used both kinds on many engines. I can't say I favor one over the other.
Test show the gapless produce just a bit more power. Is that small bit worth the extra big bucks,.... not in my opinion.

 

I've got Total Seal Gapless 2nd's in my LT4; you'll need to install an orifice with around a .063 diameter opening into the PCV system, as the increased vacuum creates too much flow thru the stock PCV system.
I also notice my oil does not darken up nearly as fast with the T.S. rings, reduced blow-by I assume. Purchased the file-fit / plasma-moly faced set thru martel bros...I've got my leak down gauge loaned out or I'd go out & check the leak rate for ya' tonight, it was low the last time I checked…1 or 2 percent, only have 5K miles on my engine though.

 

I've never used them myself, but here's my take on them...

The only influence they're going to have on oil control is that you won't have a gap in the second ring for oil to leak by into the cylinder....that's the only difference. Personally, I prefer to file-fit the rings to the appropriate gap and NOT have a "gapless" 2nd ring like the Total Seal is, because I feel it has the potential to hide problem spots in the motor.

My other thought on them is that the gapless 2nd ring will do nothing more than capture spent gas between the top two rings, where it's not doing anything for you. My feeling is that you need to let it pass by the 2nd ring so you can do something with that little bit of extra volume (thinking in terms of race engines here). The only time I would go for a "gapless" ring is for the top ring....then you're no longer trapping spent gas between rings, taking up useable volume.

 

Thanks superlund. Anything that keeps combustion by-products out of the crankcase sounds like a good thing to me. :cheers:

 

Thanks zyla. I was trying to discount the $ difference, because I don't think there is a great difference between the total seal ZGS and a good set of Speed-pro double molyring for example. :cheers:

 

Thanks z51. I know where you're coming from with the trapped gas between the top and second rings. I know some manufacturers are recommending opening up the 2nd ring gap to stop ring flutter at high RPM. I will be running a TPI, so shouldn't get into the realms of that much flutter. I am seriously considering KB pistons as well and they have to have an increased top ring gap due to the higher top ring position on the piston.
My thoughts on the ZGS rings are that the function of the second ring is as you know twofold. A secondary oil ring primarily and a secondary compression ring secondly. With this in mind, the top ring of any type of ring package does the bulk of the work as far as compression is concerned, the second ring should reduce by-products getting into the crankcase and thereby contaminating the oil (as noted by superlund) with the low leakdown rates. Although I realise leakdown rates are only conducted when the engine is stationary and may or may not totally reflect conditions in a running engine with gapless rings. The other interesting point is the requirement for an orifice to reduce the flow through the PCV system: Now I don't know if that is good or bad. I remember engines that didn't have PCV systems and in cold weather they got gunked up bad. There again lubricant technology has improved to combat the old sludge problem as well. I've run fully synthetic for years and my crankcase is spotless. (engine in bits) More food for thought......I am still not sure, I think I've got more questions now than before..... :rolleyes:

 

FWIW..I believe you'll find that "ZGS" brand rings are made by Child's & Albert, not Total Seal.
Good luck with your choice...

BTW, I also run a small oil seperating filter between my intake manifold vacuum source & my PCV valve to help seperate & eliminate any oil from being pulled into my intake tract...


[Modified by superlund, 5:22 PM 2/27/2003]

 

ehuuuh...oil seperating filter...more details please...sounds interesting.

 

z51 you are not traping the gasses between the two rings because they can come back up past the top ring. what the total seal ring will do is virtually eliminate leak down completely to increase horspower in theory and you said you can get winston cup parts. allmost all the teams maybe all of them run a gapless 2nd ring package :cheers:

 

The PCV filter is no secret... I first used one on a 914 with Total Seal rings in 94' I actually learned about it through a group of guys that use the 914 motors for desert racing, they were all using gapless rings at the time & had came up with the filter as a fix for the high flow thru the PCV system.

I believe a group of C5/Z06 owners are using the same trick...do a quick search.

Anyway here are a couple pic's. The filter used is the same type used for compressed air systems.
Image function won't resize these, so here's the links...
http://members.***.net/jbailey9/PCV%20Filter.JPG
http://members.***.net/jbailey9/PCV%...%20Routing.JPG




[Modified by superlund, 7:38 PM 2/27/2003]

 

My brothers runs them in his 461 BBC and he has put a ton of miles on it with 4.10 gears...motor should be tired by now, but it runs very tight and strong.

Problem is it has an oil burning problem...can only be traced to the rings...he has been working a restrictor in the PCV, but still burns 1 quart per 300 miles.

I love the leakdown rate that I have seen articles on, but the oil burning problem is a real problem...

:)

 

I see there are positive results. The local shoppe isnt really a believer saying it causes the top ring to flutter... but they calmly admitted theyve never tried them. What would be better for higher rpm motors? How about longevity? thanx. :cheers:

 

IMHO the ring flutter would only be an issue in extremely high RPM situations, I guess you just need to ask yourself how high are you really going to rev the motor and for how long? In my case I can't see my LT4 motor with a hydraulic cam going above 6500 -6800 RPM and then only for a very small amount of time...90% of the time it will be below 5500 RPM.
I'm not really sure the ring flutter issue has been put to bed, or proven. It was my belief it was still open to debate amongst the various tuners/builders/teams?

I would also agree that you just can't go wrong with standard hand gapped rings; I always preferred ductile iron speed-pro plasma-moly file fit rings myself.

 

Yes the gas can physically come back up in a static environment...but it won't because of the fluid dynamics involved when trying to evacuate the cylinder. What happens is that you make it harder for that gas to be evacuated because it now has to all come up past a very small gap in the top ring. Why do you think piston manufacturers are raising the top ring land? It's because burnt gas is "trapped" in the crevice volume there...not statically trapped like closing a door on it, but dynamically due to pressure gradients, flow paths and such....and this is on the TOP ring, where you don't have another ring with a small endgap providing the other boundary! The less volume taken up with spent gas is more volume that can be filled with fresh charge.

None of the 4 Winston Cup engines we have (from 3 of the top teams in NASCAR) have gapless 2nd rings. The reason being they gas-port the pistons, which takes care of cylinder sealing issues. They also rebuild the engines every 500 miles. And believe me when I tell you that they're running significantly higher combustion pressures than our pathetic street motors are...though admittedly we don't have gas-ported pistons in our motors (it would be a bad idea to do so).

I could see the point of them on an endurance racing engine, where every little bit of power adds up over a period of time, and there's enough hard miles on the motor to significantly wear on it, but in a sprint motor or a street motor (where I'd much rather know that I have a worn top ring and/or oil ring), I just don't see the point.

 

I used them...they seal great at low speeds, but at rpm they flutter and smoke.

 

looks like a water trap?? So you just have to check and drain every so often??

 

Had them in my 86 and they didn't break in the way they were supposed. Burning alot of oil. About a year later I ripped the engine apart again and had a total rebuild which im about to finish in about a week or so. Machine shop installed new gapless rings. If I had known he was gonna do that I'd opt for the regular rings. Didn't see that much of a difference. That's my 2 cents ;)

 

Actually it is a water trap/filter...gotta' drain the bowl every so often depends on how hard its driven, that pic was taken at install so everything was still clean & pretty. Works good though most all cars will pull some oil thru the PCV system, I just don't like to get synthetic oil pulled into the combustion chambers..stuff doesn't burn clean & leaves carbon build up on piston tops, upper ring seats etc...

 

I used them in the last 2 engines I built, and both had oil consumption problems. I switched back to Speed Pro File fit rings. I've heard they can actually unseat the top ring. Just my experiance with them.