[chiphead]

Sooo, any concerns running a 1.5, 1.5, 3mm ring pack in 4.155 bore with under 200 shot in a 4" stroke street/strip motor? Any experiences with the TS AP stainless rings?

Any concerns with ring flutter, durability, oil control, ring seating, etc? The reason I'm asking is I see that a lot of aftermarket pistons (race-tec, Mahle, etc) have gone to the metric ring packs for forged pistons under 4.25" bore. This must mean the ring pack has proven itself. I also understand you can't use (well, it's risky) moly ring facing in a nitrous motor. That's why I'm looking at the TS AP stainless rings.

Any input? I don't want to be the pontiac guinea pig on this deal.

[mgarblik]

I can tell you what we ran and our experience. We have been out of nitrous Pontiac stuff for 6-7 years now, so the info may be dated. We ran a .017/.043 Dykes top ring. We ran it down .250 for best results leaving room for the exhaust eyebrow. Ring material was heat treated ductile iron, sometimes called tool steel, incorrectly. Trade name HelFire from Federal Mogul. Sealed great, kept it's radial tension very well. We also ran molly filled premium ductile iron top rings to 300 HP nitrous but as you mentioned, you don't want to detonate or you will damage the ring and they lose radial tension much sooner than the heat treated rings. No experience with stainless steel compression rings. Our second ring was a 1/16" Napier style ductile iron ring, Great secondary ring, good oil control. Oil ring we used a 3/16" stainless ring, standard tension. This combination worked very well for us. The only ring problem we had to deal with multiple times was proper end gap. If you are spraying hard, you need huge end gaps. When we were spraying 500-600 HP, we would Butt and destroy a ring at .040" gap. Ended up at .045-.047" gap and no more issues. That's around .010" per inch of bore. But that's what our engine wanted. On a 4.185 bore you are going to want .035" minimum spraying 200 HP. in my opinion. We never saw an issue with the wide gap. Good luck with your engine.

[mysticmissle]

I have the same rings on my race techs. THose are LS rings and we know how everyone raves about their abilities. I used the Total seal rings also, just not the zero gaps, I will never buy another pair of those.
I am going to spray about 200 to mine on a 455 +030. gap them right and It should be like any other ring and nitrous. The reason you are seeing them on the new pistons is availibilty of a quality rings in these sizes and the benefit of the thinner ring sets. It is a win win

[chiphead]

Dittos on those LS rings. I built a 5.3L for my truck, and even with imperfect bores those rings sealed up great.

Which specific ring style did you use, the Advance Profile or something else?

I'm going to use a non-gapless "conventional" ring, but stainless with the CrN coating. From all the reading I've been doing, it doesn't seem like there is any downside to the metric rings. Just use the "standard" oil ring tension and a napier 2nd ring. I'm not going to use a dykes top ring because it's a street motor. I'm going to use a barrel-face or something similar for a top ring.

It seems like such an easy choice I must be missing something?

[mysticmissle]

i will check part number, I will say this, if you do not have a tapered ring compressor for your bore size, buy one! real pia with the old band style due to the very thin oil rings

[JSPONT]

Cool test on rings.

https://youtu.be/-29IWc-zrv8