[Qball]

I’m getting ready to file fit my rings in my engine and I really don’t know what the spec is supposed to be. I’ll be using the tsr-cr0690-35 file fit rings. My bore is 4.155 and stroke is 4.250 on a Race Tec forged piston.

Anyone know what the proper gap for the 1st and 2nd ring is proper?

Thanks.

Edit: this engine is normally aspirated and no nitrous.


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[hurryinhoosier62]

.004 per each inch of cylinder bore on the top ring, slightly wider on the second ring. Figure a top gap of .016-.018 and a second gap .020-.022.

[Qball]

Originally Posted by hurryinhoosier62

.004 per each inch of cylinder bore on the top ring, slightly wider on the second ring. Figure a top gap of .016-.018 and a second gap .020-.022.

Thanks, I appreciate it!


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[steve25]

What will you be using to gap the rings?
If you will be using a file , only use the file to push in from the ring face to its rear, if you pull back you can flake the Moly band of the face of the ring and start ware problems right from the get go!
Also note that Moly face top and second rings ( sometimes the second ring is non Moly) should go into dry bore's and they will seat near instantly, you only need to lube up the piston skirts and have a very very light film of oil on the top and bottom of the ring.

[chiphead]

But if the engine will be stored for some time before install, you'll need something to protect the cyl walls. I usually use WD40 or a fogging oil. For my 434 build, I'm going to use the TS AL8 ring lube and the Quickseat on the walls. Looks like really good products to promote wall prep and ring seal.

Was there no gapping instructions with the rings or the pistons??? If you're using a race-tech 2618 piston, that would indicate an application that justifies opening the rings to .0045 to .005 per inch of bore. Not much downside to being slightly too wide, and a lot of downside of being too tight. And ditto on Steve's filing instructions . File toward the inside on one side only. Lightly deburr edges with a jewelers file afteward. Keep gap square.

[Qball]

Originally Posted by chiphead

Was there no gapping instructions with the rings or the pistons??? If you're using a race-tech 2618 piston, that would indicate an application that justifies opening the rings to .0045 to .005 per inch of bore. Not much downside to being slightly too wide, and a lot of downside of being too tight. And ditto on Steve's filing instructions . File toward the inside on one side only. Lightly deburr edges with a jewelers file afteward. Keep gap square.

Heck of a good question! I haven’t dug through the box of pistons and rings too much. I was holding off until I was ready to install. All my stuff is at my buddy’s place in his nice, heated, giant shop/garage. When I get back over there I’ll dig through everything and see if there’s a spec.




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[77 TRASHCAN]

I polish the edges of the gap ends with something like 250 grit wet/dry sand paper, to make sure there are no sharp edges...file might be faster...

[Lee]

I just checked the notes from a 455 I built 6 years ago, using Race Tec's and TS rings. This motor was bored to 4.165". I used 0.018" top and 0.020" for second rings.

I talked with the owner about a year ago, and he was still very happy with the motor.

Oh, Total Seal makes a special lube for their rings, a light oil with a blue tint to it.

[Qball]

Thanks, everyone, for the great information!


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[77 TRASHCAN]

Glad to see you are getting to work on the engine again.

[Qball]

Originally Posted by 77 TRASHCAN

Glad to see you are getting to work on the engine again.

Thanks, man. My block was in machine shop jail for nearly 2 years. I finally had to pull it out. Luckily, all the machine works was done and the rotating assembly had been balanced. I just need to give the block a final wash and can start assembly. Maybe before the end of Summer I can be driving this heap again!


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[77 TRASHCAN]

Maybe by the time you get it fine tuned, the Power Tour will make a run close to you, again.

[JSPONT]

Are you going to add nitrous? If you are ring gaps should be wider. The ring manufacturer usually has paperwork in with the rings.

[Qball]

Originally Posted by 77 TRASHCAN

Maybe by the time you get it fine tuned, the Power Tour will make a run close to you, again.

Sigh....yeah, maybe.


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[Qball]

Originally Posted by JSPONT

Are you going to add nitrous? If you are ring gaps should be wider. The ring manufacturer usually has paperwork in with the rings.

No nitrous. Just good old fashioned normal aspiration.


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[JSPONT]

Okay then you are good with the advise given. Good luck. There are manual ring grinders. They work well and are no expensive. They also keep the file "square"

[Cliff R]

Don't forget to check the oil rings. Ran into several batches of Total Seal standard type file fit rings sets where the oil rings butted together in the bores and had to be opened up some.

I also had a bad batch of lower iron rings show up here and they were to brittle you could NOT get one over a piston without it breaking into 2 or 3 pieces. Total Seal very quickly replaced them and didn't even question the issues we were having so I supposed they knew about it already. That was about 3-4 years ago and we've done a few since and the bottom rings were fine, but still something to keep in mind.

Far as end gaps go, for decades I set the top rings at .018" and bottom rings around .014-.016". Around 2000 we started hearing about potential benefits with opening up the bottom rings so I went to .018" on them. Zero issues before or after that move and none of our engines have ever had any problems in that area.......Cliff

[steve25]

If I am not mistaken the extra second ring gap is only needed on forged pistions , on cast Pistons having the second ring set for the same gap as the top is all that's needed and will present no problem.

[Qball]

Originally Posted by steve25

If I am not mistaken the extra second ring gap is only needed on forged pistions , on cast Pistons having the second ring set for the same gap as the top is all that's needed and will present no problem.

I will be running a forged race tec piston. That’s good info for cast vs forged piston ring gap.

Originally Posted by Cliff R

Don't forget to check the oil rings. Ran into several batches of Total Seal standard type file fit rings sets where the oil rings butted together in the bores and had to be opened up some.



I also had a bad batch of lower iron rings show up here and they were to brittle you could NOT get one over a piston without it breaking into 2 or 3 pieces. Total Seal very quickly replaced them and didn't even question the issues we were having so I supposed they knew about it already. That was about 3-4 years ago and we've done a few since and the bottom rings were fine, but still something to keep in mind.



Far as end gaps go, for decades I set the top rings at .018" and bottom rings around .014-.016". Around 2000 we started hearing about potential benefits with opening up the bottom rings so I went to .018" on them. Zero issues before or after that move and none of our engines have ever had any problems in that area.......Cliff

Great advice on the oil rings, Cliff. I appreciate that.

Is there a recommended gap for the oil rings or is it just important that the ends not be touching? Do they not grow at all during normal use?



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[Cliff R]

Those thin expander rings aren't going to grow much way down in the bores, they just need a little clearance so they don't butt together. I just give them .020" or so, they aren't fussy.......Cliff