Use stock specs for ring gap on 14:1 piston?

 

Sorry I don't recall except to say it seems to me that they were pretty loose. Although when I did the stock bore I think I used stock ring end gaps. But again Im not sure. Hopfully someone will remember. But for now...you gotta bump up. [img]i/expressions/face-icon-small-wink.gif[/img]

 

.018 Normal .027 NOS

 

Stock piston is cast aluminum, your new piston is forged aluminum. They swell at different rates, ring end gap will be different between them.

All forged pistons are not created equall! Example: They each have different silicon content which makes them expand at different rates.

Bottom line the piston manufacturer is the only one who can answer your question.

If those ends butt under hard load its like throwing the brakes on and the rod can pull the pin right out the bottom of the piston!!! I got a few of these laying around to prove it. Ouch! Its not purdy...

 

MrHP ,didn't see your # or you don't give those out mybe?

 

 

thanks everybody, I got the ring gap specs from the dealer I bought the piston from, he saw my post and responded with PM, I'm on 13 hour night shifts this weekend and hard to get a hold of people during the day while sleeping, not to mention weekends its harder to get ahold of anybody!

thanks for the clarification MRHP, that also explains the difference in piston diameter I've often wondered about, my JE and CP both being smaller in dia. than the cast stocker.


yjacket to my knowledge all aftermarket pistons offered by JE and CP are forged.

 

Dude, there is very little talk of ring gap on this forum at all man, and that is a shame!

Yes ring gap is very important, more than most know it seems!

There is no rule of thumb for ring gap, as mentioned my MrHP the only one who can answer that question is the manufacturer!

And it won't be the same for every piston of the same type either, cause they don't all have the same rings! For example you may have a CP 12.5:1 forged piston with gapless second ring, and somebody else may have the same exact piston with no gapless ring, and the gap specs may not be the same! (yes gapless rings must be gapped!)

 

 

I may be wrong in my assumption, perhaps the only reason for a slightly smaller dia. is due to higher compression creating higher combustion temperature, I dunno.
but each one being slightly different in chemical makeup certainly makes sense in terms of thermal expansion, thus the subtle differences in ring gaps.
bottom line - consult the manufacturer for ring gap specs.