I don't have any personal experience with the gapless second rings but I have personally seen a 316c.i. splayed valve Comp motor pick up 20 average horsepower by just changing to Total Seals Gapless tops from a conventional type ring.

 

But you mean Top ring correct? what second ring/oil ring was on the piston?

 

The links above have been interesting but a little lacking in hard data.

Well, I may consider looking into going back to gapped rings for my summer tear down and freshen up with all of the latest discussion of Gapless 2nd rings losing sealing at high rpm. The only issue is, I'll be changing to a lower compression piston and upping the boost at the same time. So a true A:B comparison is out of the question. I'm at 1076 RWHP right now using C&A zero gap seconds. If these rings are somehow a design that is not capable of controlling sealing at this power level than I must be giving up xx? amount of power. If this is indeed the case I will definitely make the move back to a standard ring design.

I could see why the Hot Rod article showed a gain with a 400 horsepower motor with the ZGS rings. The cylinder pressure is probably not high enough to upset ring sealing. I would really be interested in seeing some test results that would really test the metal of the rings (pun intended) in a higher HP application than the Hot Rod test. If anyone knows of a link that has non-biased quantitative data that would be great.

 

Something would have to be seriously wrong with the engine in question to see that much difference with any ring change unless the first rings were not made correctly for that ring groove or damaged. When something like this happens at a shop you know not to have your stuff done there if they actually think they gained that much because of the rings.

Barry Robotnik put it quite well and he was in teh ring business for decades:\

""While employed at Federtal-Mogul, I had access to test lab data and resources far beyond those available to any aftermarket supplier. Since Dana was both a competitor as well as a supplier for many of our performance rings - - I had access to their resources as well.

Between the two corporations we had about 60-70% of the world's piston ring manufacturing - both OE and aftermarket. Much of the remainder was held by CoFap, Riken and NPR. Couple our Cray computers, sophisticated software modeling, the engineers, dozens of dedicated dynos - - and the even more elaborate resources at every single OEM - - and one thing was very clear. None of them - - zero - - came up with a gapless second as an honest viable product.

Did not matter how high the efficiency pressures from EPA, CAFE, or competition for bragging rights regarding durability and power, nor the price of the vehicle - - Ford or Ferrari or Viper or Vette or Aston Martin - - none of them went gapless. None. Exactly one went with a 2 ring deal - - a Nissan. That to me is a very strong statement in support of the traditional 3 ring piston.""

 

I worked at SAM for of course several years and know hundreds of students around the industry. I know of NO competive programs with testing ability that use any second gapless ring setups anywhere in the world. OTOH I know of tons of mom and pop shops and small lower end places that use them because of the hype. Several LS1tech vendors have already been through the ringer when these total seal gapless second stuff is used and none I know of anymore will allow their use and provide any warranties besides the ones with no engine building backgrounds. It's something you have learned or that you are going to learn.

BTW I have them on my turd mustang and they are alright at 300 RWHP but I have some running crankcase pressure even though I leak down at 2% or better. Also I use Total Seal rings a TON but just not the 2nd Gapless variety so the company is great to work with.

It's like the thread on Speedtalk where only one guy with a small shop thinks they are great and every one of the big Comp Eliminator and Pro Stock guys know they don't do anything good or are even bad. I have already fixed maybe 8 different LS1s with oil burning problems already by just changing to conventional rings.

I wouldn't even ever use the top gapless rings ever on a street car. Most of these exotic rings work great on a real race engine with some vacuum but again you will never see an OEM that has to meet emissions and longevity requirements using them, not ever.

 

Erik,
I'm glad that you jumped in here on this subject with your last two posts. I've had several delays in actually getting started to assemble my engine and I may just keep my Napiers and oil rings and switch to conventional top rings rather than the gapless variety. I take it that's what you would advise me to do.

Thanks,

Steve

 

I would most certainly. Another very well respected LS1 shop tried using the tops here as of late and had smoking issues and also did not pick up any power whatsoever. I suggested they simply change back to the conventional rings which are also from Total Seal and they run great with no smoke now.

We have used the Total Seal top gapless on some racing stuff and seen very small gains so I think it's a good idea but again that was on an engine with more than 15 inches of vacuum as well. I don't think I would use them on a regular street wet sump engine myself but who knows? The LS1 throws a lot of oil around and on the walls.

 

Thanks Erik,
As I have said before, I respect your opinion very much!

Steve

 

Erik,

I was hoping to get some more insight from you in this thread. In fact in that call I was hoping to get from you (sorry I didn't pick up today, can't use my cell at work), I was hoping to discuss the issue of gapless tops in the motor I left at your shop last week.

I guess you said it here.....gapless rings on a street motor are not recommended. But I have to rebut, only for the sake of healthy argument:

I would tend to think that OEMs would use the cheapest possible method that gets the job (meeting emissions/longevity requirements) done. And assuming that gapless rings do provide some benefit, the marginal gains would not be worth it to OEMs. For those of us seeking to get every last pony out of our setup on the other hand......

And as for the comment on pro racers not using them...I can see where in cars that don't rack up the sort of mileage that a daily driven LT1 for example does, that any marginal initial gain would still not be worth it. I just don't like the idea of getting some good hard mileage on my motor and knowing I'm losing power to opened ring gaps.

Also you mention many problems of users of gapless rings. Is there no daily driven car out there with gapless top rings that IS NOT experiencing any problems? You imply set-up problems on the motor that experienced a 20 hp gain when switching to gapless tops. The same thing goes for setting up a motor with gapless rings...who's to say those with oil control problems on gapless combos aren't also suffering from substandard assembly/break-in?

Again, I highly respect your opinion, and I only pose the above arguments for the sake of learning. I only want to do this motor ONCE, and when I get done I want to KNOW it's not leaving anything on the table. Summary: given my arguments above, would you still discourage gapless top rings? Your rebuttal is greatly welcomed.

 

Can you elaborate more on the smoking issues they were having and why?

 

Also, the above inquiry for rebuttal is geared mostly toward my LT1 build (so I guess no LS1 problems with throwing oil on the walls as you say), with a deep Canton oil pan, and hopefully minimized windage.

 

They were smoking with the gapless rings and the rings were changed back to conventional and the smoking ceased. Same everything else but the rings.

 

The cost difference is nothing to an OEM that can make them very cheaply in bulk. They have been tested and they are not used on ANY oem applications. The Napier is also a very expensive 2nd ring but it IS used now by many and many more use it each year since it HAS been shown in testing to work slightly better than the conventional 2nd ring and takes less friction to run thus truly making a little more power often.

Racers will use something that costs triple as much if it will make them even 5 more hp and I don't see guys that build real race engines using the second gapless stuff at all. Believe me they have all tried them quite often and there's a reason you don't see them especially in high end shops ever.

The place you lose power is ring seal. The end gap is hardly anything compared to incorrectly honed cylinders or bad pistons or rings. 99 per cent of the sealing of a cylinder is the fit or flatness of the ring to the ring lands on the piston and the roundness of the rings vs the roundness of the bore.

The only force holding the rings down against the ring lands is the pressure difference above and below that ring and this is compromised by the second gapless rings. The rings do have some built in radial tension but it is not all that holds the ring against the cylinder walls as the rest comes from the gas pressure acting behind them.

The ring end gap just needs to be a size that does not butt if the rings get too hot.

 

Yes top. They were the diamond cut rings with the napier second. .043/.043/3.0mm.

There may have been other problems they corrected but I didn't do the motor so I don't know.

 

I am aware of all of the above, so I have recently been considering gapless TOP rings and napier second rings for my build. So, cost and general usage trends aside, is there any reason you would still discourage the use of the above ring package in my particular setup? If so, WHY exactly?

 

Well I think that's what my problem is. I swapped heads and cam this weekend. I have a stock-ish cam and stock heads now that pull quite a bit of vacuum, and the smoking got worse. It's gotta be in the rings, there's nothing left to change. Any idea why the gapless rings smoked so much?

 

Yes seriously I have yet to see them work on anything other than a race engine. The people on LS1Tech that have used them have experienced smoking issues that were cured with the return of the regular top rings. I do not know all the reasons why though other than they were all pissed off for sure.

Saying that though they worked fine on our race engines with vacuum pumps and seemed to possibly pick up a little power but still it's very hard to say. I know Judson at the school is also not a believer in any of them except the top ring gapless but even then very few still use it so far.

Basically why fix something that isn't broken in the first place? You need to find some serious engine builders that really have tested these rings that recommend them heartily and for a regular street car. I have found none that will so far and like I said and I know lots of real shops that have run them a lot and the regular rings a lot and I know what they use.

Like I said it's not because they are trying to save money it's because they want to win and they can't give up any power whatsoever. Also as I said before it's nothing bad against Total Seal the company as I use their rings everyday and the same with Childs and Alberts as they both make awesome products and piston rings.

As has been said already, NONE of the oems will touch any of this stuff. If they were so good why wouldn't anyone be using them at all? DO you want to be a guinnie pig for how this stuff works on the street or have to pull them if they smoke?

I like you was also very intrigued at first before I knew how little the gap mattered anyway at least on the power stroke but I was still interested in the intake stroke possibilities that seem to be the plus of the gapless but still I could not find anyone that had seen much if any gains in testing but only losses and these are guys that actually know what they are doing and WANTED to see gains bad.

 

I think the regular 2nds and napier 2nds both also like a little pressure and blowby on their gap at least in as far as oil control goes. Some of the NASCAR stuff has a MUCH larger second ring gap than the top. So does most race stuff and a hell of a lot of OEMS these days.

I don't know the exact nature of your problems thunder550 but several shops I was speaking of had these problems with any hone job they tried while running the top gapless rings and after returning to the normal gapped tops the oil control problems dimished or vanished like I said.

I do not know anything about your setup though or why it is consuming oil so fast. It could be many things to tell you the truth as well as the rings but not necesarily the rings.

 

Great thread and links... so what causes smoking in the gapless TOP ring configuration? Does the top ring flutter and oil gets by? I don't get it.

 

Well for my particular setup it has to be something in the shortblock. I have eliminated all of the typical causes for oil consumption (PCV system, valve seals, valve guides, intake rocker bolts, etc). When a higher vacuum cam burns more oil, at that point it seems like it has to be a ring or cylinder hone problem. The oil either comes in from the top or up from the bottom, and I'm pretty sure at this point it's not coming in from the top.

In case anyone is interested, here's a short vid I shot of my truck starting up after I let it sit and idle for about a minute, then shut it down. 3g2 format, requires Quicktime 6.5 or higher.

I pull about 18 hg-in of vacuum with the LS6 cam that's in there now, as opposed to 10 that I was pulling with the 235/239 that was in there before. The oil burning is much worse now than it was before.

Shortblock is composed of a Callies Dragonslayer 4" stroke crank, Compstar 6.125" rods, Diamond 11576 pistons cut for 1/16", 1/16", 3/16" rings, and TotalSeal gapless stainless top ring, napier second, and standard tension oil ring.