Justin 87 GTA.

Please, does anyone have their number.>thanks. i need the ring gap for a blower motor..building it today.

B4Ctom1

I am holding in my hand a 2000 Speed-pro #X-3009 catalog, they purposefully do not list any phone numbers in it. But there is a chart.

It says:

ring end gap recommendation guide

speed pro top rings
(ductile iron & HF479)

moderate performance --- .004 per inch of bore diameter
drag racing, circle track --- .0045 per inch of bore diameter
nitrous oxide - street ----- .005 per inch of bore diameter
nitrous oxide - drag ------- .007 per inch of bore diameter
supercharged -------------- .006 per inch of bore diameter

speed pro 2nd rings
(cast iron)
moderate performance --- .005 per inch of bore diameter
crag racing, oval track ---- .0055 per inch of bore diameter
nitrous oxide - street ----- .006 per inch of bore diameter
nitrous oxide - drag ------- .007 per inch of bore diameter
supercharged -------------- .006 per inch of bore diameter

notice: most of the second ring gap recommendations are higher than the top rings. recent testing has proven that a larger second gap increases the top rings ability to seal combustion. the larger "escape" path prevents inter-ring pressure from building up and lifting the top ring off the piston allowing combustion to get by. many engine builders have reported lower blow-by and horsepower gains at the upper rpm ranges with second ring gaps. also, almost every new car made is using this inter-ring pressure reduction method to lower blow-by and emissions and to increase engine output.


thats all they have in there. dont be phased by the fact that it says ductile iron or cast iron, nomatter if you have "chrome" faced rings or any model of moly faced rings this is what they are made of. I always laugh when I see someone telling me about thier "chrome-moly" ring set. I'm like, "one or the other bub, not both."
But I cant tell you that this "inter-ring pressure" they speak of is no laughing matter. I have seen numerous cars with total seal gapless rings rip the top off of the piston in power adder cars. Here is a picture of a TRW forged piston using speed pro rings where the top ring was gapped wide like the instructions to prevent ring end butting during expansion from being close to the chamber. We decided to go a little smaller on the second ring since it was further away from the chamber. We got lucky and never even knew there was a problem until the end of season tear down. this was a SBF on nitrous. if you look closely you can actually see what is shown poorly in the picture, the thick "crown" or top of the piston is actually bulged upward as well! It was a learning experience. Luckily it didnt ruin anything or cause a huge cost of money. Now you can see also without ruining your own stuff.

Justin 87 GTA

iTrader: (3)

well, i just set them at .024-.026. The top rings are closer to .024 and the bottoms are like .026 or a little more.
>>>>Problem is,.. i screwed up a few BOTTOM rings. One is like .035 and 2 are over .040. I don't know how i did that, but i did. Anyway, my friends that have built many motors,.. say it's fine. IT isn't any problem... I think it's ok too,. cause they are the bottom rings. Anyway,.. what do you guys think? I'd hate to have to wait to order a new set and spend more money on top of it,.. i just want to get it together. What do u think?

83 Crossfire TA

iTrader: (2)

Will you ever really notice the difference? I doubt it. But you'll probably wonder about it every time something weird is going on or if it just won't run what you expect.

Do what you feel is right… if it was me I'd put new ones in. Very rarely do I settle for "good enough" if I can have "right."

Justin 87 GTA

iTrader: (3)

yeah, but the theory is also, that when i file fit them,.,.. the block doesn't even have a torque plate on it,.. so they may not even be exactly .024 when the heads are one. the cylinder might distort, and the gap may shrink even more,.. either way,. i think because it's the bottom ring,.. i can leave it alone. It's a low compression motor,.. and its probably gonna be much better than if somekid did them at the machine shop.. so thanks for the input,.. but if you think it shouldn't matter then i'll leave it. There are other weak links,.aka rods,..etc. I can't see this causing damage. thanks for the reply though.

B4Ctom1

I have seen lots of 4" bore variants N/A running in the .014-.016" range on circle jerkers before the total seal rings were commonplace. I WOULD NOT SUGGEST THIS. Its just an observation.