Piston ring gap questions

[67MPRFAN]

Hello all what would be an acceptable various in piston ring gaps. I'm using total seal rings CR9190-125 which is 4.375 bore gap was supposed to be .020-022 from their tech site, I'm was .021-.024 on the top ring and the second ring was .010 they told me to file fit them which from their website isn't supposed to be file fit ,

 

[69L48Z27]

How about that. Same here. I bought fitted Total Seal rings and had the same thing. Called the tech line and they told be to open them up. I forget now but I think they told me .024 or 026 on top and second, they told me to make them the same.

 

[67MPRFAN]

I had 1 that was .030 on the top when I spoke with them about it that sent another 1 at no charge... I made my 1st attempt at file fitting and messed up so I just ordered another set hopefully this 1 will be better

 

[69L48Z27]

I don’t have equipment to file fit and ended up taping a file up and put it in the vise. Worked out okay. Just tedious. Thought buying fitted rings was the ticket.

 

[1 Wild R/T]

Hello all what would be an acceptable various in piston ring gaps. I'm using total seal rings CR9190-125 which is 4.375 bore gap was supposed to be .020-022 from their tech site, I'm was .021-.024 on the top ring and the second ring was .010 they told me to file fit them which from their website isn't supposed to be file fit ,

What Pistons are you running???

 

[67MPRFAN]

What Pistons are you running???

Total seal CR9190-125

 

[1 Wild R/T]

Total seal CR9190-125

Not the rings, what pistons..

 

[67MPRFAN]

Not the rings, what pistons..

Sorry Ross Flat Tops 99538

 

[dvw]

To big a gap doesnt hurt a thing. To small can break a piston. The old theory was small gap on the 2nd ring as it ran cooler. Current thinking is run the 2nd larger than the top to prevent the top ring from unseating . Unseating is caused by cylinder pressure that passed by the top ring and became trapped between the 2 rings. Larger 2nd gap is the escape route.
Doug

 

[67MPRFAN]

Thanks Doug ..... Great job on racing over the weekend. How much of a various is too much between rings gaps my tops were .021-.024 with the exception of 1 being .030

 

[33 IMP]

Every time I see someone using a power adder, the first thing they do is open up the ring gap, as a precaution. I agree with Doug, I wouldn't worry about too much, I'd worry about too little.
The last 440 I did, i set them to .026 to.028. I have a nitrous setup, not planning on using it on this motor, but wanted to give myself the option.

 

[1 Wild R/T]

Sorry Ross Flat Tops 99538

Cool, good pistons.. Reason I was asking is Hyperutectic pistons required a bigger gap, about 1.5 times the gap for a forged piston.. Which your numbers are a little bigger that typical so I was thinking you might be going that direction...

The normal spec for a purely street engine on the top ring is .004 per inch of bore so a 4.35 bore gets a gap of .017-.018

Higher output or harder use requires more gap, nitrous certainly requires more gap...

As has been stated, a little to wide is much better that a little to narrow....

Second ring is typically .001 per inch wider than the first ring....

 

[67MPRFAN]

Okay Thanks everyone for your insight about this topic I'm learning as I go with this build with the help of a friend (baseball started back up) since I have another set on the way I'm going to try and set the gaps about .024-.026 to even out the spread as much as possible

 

[dvw]

Thanks Doug ..... Great job on racing over the weekend. How much of a various is too much between rings gaps my tops were .021-.024 with the exception of 1 being .030

The gap will vary .0031 for every. 001" change in bore size. Are your gaps Pro Stock/NASCAR good? No, but I wouldnt be alarmed with that spread.
Doug

 

[67MPRFAN]

Thanks for explaining that.. I guess I was looking at it consistency while building knowing everything is close as far as gaps goes.... 1st engine build so maybe just over paranoid I guess