I was orginally told not to run gapless rings on a motor used for nitrous. I plan on spraying a large shot and was concerned about what rings to get and specifically what ring gap to run. Any personal experience would be greatly appreciated.

 

please read this https://www.thirdgen.org/techbb2/sho...hlight=gapless

 

So you would recommend a speedpro ring such as the "hell fire"? I remember seeing that post. Thanks for the link. Any suggestion on ring gap, or should I talk to ross for that. I had planned on getting ROSS nitrous pistons, just to be safe. I also had plans to drive this car a lot, and was cencerned about excessive blowby b/c of the ring gap I would have to run to keep the ends from butting and locking the piston or breaking a ring or ringland. Any advice on this?

 

the hellfires sound good but I know nothing practical of them. the thing I cant understand is that the last time I looked in a ross catalog the nitrous piston said next to it (good up to a 150 shot) what the hell does that mean? hell stock pistons can do that. doe sanyone have a page of the ross catalog they can scan? I'm curious to either see the page I'm talking about with the low rating, or a newer page showing a similar note listing a higher hp rating.

 

I've been talking to some people in the business and they were telling me that "off the shelf" ROSS pistons would handle a 200-225 w/o a problem. But I would also like to see a statement from Ross to back up that rumor.

 

you wont see a statement like that from them because that makes them liable.

 

radio edit

 

I guess they are pretty good but the TRW's are the most dense piston for off the shelf, unfortunately this translates into "heavy" as well. If you are running a good rod and not reving to the moon then its weight is of no consiquence.

 

On my C & A rings there was a spec sheet...I cant think of a set of rings that are file to fit that I've worked with that don't come with that sheet. FWIW I set my rings up for a 150 2 stage (300 at full go) and the measurements broke down like this:

.0008 mutiplied by the amount of N2O in hundreds of HP
(ie. .0008 X 3) for a 300 hundred shot

Multiply that number by the bore of the motor and that gives you the end gap

So, for my motor it was .0008 X 3 X 4.030 = .009672

HTH

 

there is a cool one in the tech section of the kieth black site as well

 

The thing is that when fully heated, you really want to end up with a slightly smaller gap in the first ring then the second. Typically, since the first ring sees the chamber heat that means that you actually start with a larger gap.

On an engine like that typically I’ll look at what everyone has to say about what the correct gap is and give the most weight to the piston manufacturer’s recommendation and then the ring manufacturers. The piston manufacturer will know what properties their pistons have and how much heat their particular design transfers to each ring.

After looking at all that then ask yourself “am I going to be more pissed if I’ve got a little bit more blow by or if I butt the rings and blow up the engine?” Then choose accordingly.

 

Thanks for all the replies. You guys have been a great help.