Hi guys!

I'm looking for any info on the CP (carillo) piston 10:1 cr for my f20c build
I'm on darton dry sleeve, I'll be running around 20psi on 91+watermeth
STOCK BORE
In my cp piston i have all specs for pistons bore, size, comp height etc but nothing on ring gap tolerance

I'm looking for infos on ring gap clearance so i dont make a puffer or a shitty engine, thats currently the only info missing for my build

 

I would email/contact CP, it depends on application. NA, NOS, and in your case FI. The bottom ring should be larger than the top as well.

 

Stewie that was exactly my first idea. Unfortunately they dont answer back for some reason

 

Me personally then; I would talk to a guy named Ken I have became quite good keyboard friends with. He built my sleeved, forged all motor H, and he does a lot of other stuff as well. IG : kensraceengines
He would probably have no issue giving you some advice on ring end gaps. That's really the only guy I would take his word over the web, If it wasn't info from the mfg.er
Which I'm sure u have been searching already, so are u finding conflicting info? Or just not trust it, or is it info for a different mfg piston that u would think is different for another?

 

So far i found so many different specs that im totally confused.

Im building this motor for reliability and some power of course. I just want to make sure i have the optimal specs so it will last long and dont need to rebuild every year

 

We have found that ring gap really isn't that big of a deal. As long as they don't touch, you're good.

 

^^^ exactly and I think also your power goal should be considered. I would still even I had to PayPal some money for the info (which I'm sure wouldn't come to) ask someone like I mentioned. I know he's specifically a big arias dealer but like above mentioned it should be mainly based on application IE. NA, NOS, FI. The power goals comment is probably more geared towards P2W clearances actually if iirc.

GL! I'm sure you'll find something.

 

From their website under FAQ http://www.cp-carrillo.com/pt-3507-pistons.html

SPORT COMPACT: Turbo/Nitrous applications to 450 - 750hp

• Top Ring = .0050 - .0055
• Second Ring = .0055 - .0060
• Oil Ring – Actual Gap = .015 - .050

So assuming stock 87mm bore (3.425) gap would be at a Minimum .017 and second would be minimum .019

 

Ring gap and piston to cylinder wall are both very important, to loose and there will be oil consumption, piston slap and it will beat up the piston skirts. To tight and the ring ends will touch and damage will follow.

The nitrous/turbo spec cp lists is still quite loose, even at 20psi on a street car, it will work but for a street car you don't need to go quite so loose.

 

The spec CP lists aren't really loose at all. If anything, that's on the tighter side of what you should run. We have gone more than 2x that number (and more) and saw no change whatsoever.

I agree piston to cylinder wall is extremely important, ring end gap, no so much. You aren't going to get "piston slap" and damage a piston with rings that are opened up a bit more.