Can you file fit any/all rings?

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cawcislo

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When you replace pistons and do you or should you file fit the rings. Or are there only certain rings that are file fit. Looking at premium sealed power rings for cast pistons 1st ring grey iron with moly, 2nd ring grey iron.

When I rebuilt a motor years a ago the machine shop honed each cylinder for the exact piston it would be home to since I’m assuming there could be some variation in width of pistons (few thousands). So if the bores are slightly different for the pistons wouldn’t the same be true of rings and therefore you would need to file them?
 
Yes, always best to file fit the rings. Some pistons have different end gap specs. KB hypereutectic pistons, and some others run the top ring higher, so it runs hotter and needs slightly more gap. .001 or .002 more gap will give a bit of insurance from overheating also, not that anyone expects that.
 
You need to put each ring in the specific cylinder and measure the gap. File the ring if required. You're factory SM will have the specification. 65'
 
New pistons are cnc machined and they are sized very close. I miked my new AutoTec pistons and they were sized all the same.

I have never file fit a set of non race rings. Rings come in file fit and standard sets which do not require fitting...they are ready to install.
 
I always check the gaps on every engine. You never know if one is boxed wrong. Like others said gap depends on piston type, use, etc. Sealed Power usually supplies a recommendation sheet with gap sizes. For HP street stuff i like to run .016-.018 on top ring. Second ring similar. Sealed power oil rings do not need to be gapped, but i usually stick a couple rails in just to make sure.
 
Krooser said:
New pistons are cnc machined and they are sized very close. I miked my new AutoTec pistons and they were sized all the same.

I have never file fit a set of non race rings. Rings come in file fit and standard sets which do not require fitting...they are ready to install.
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Pistons ain't got a THING to do with whether you file fit. That's all dependent on the finished bore size.
 
RustyRatRod said:
Pistons ain't got a THING to do with whether you file fit. That's all dependent on the finished bore size.
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DAMMIT Rob I was JUST scrollin down here to type this!!!

Rings spring OUTWARDS against the cylinder wall. There is SPACE (however slight) between the inner side of the ring and the bottom of the ring groove, in the save manner that there is a tiny clearance between the ring and the sides of the groove.
 
67Dart273 said:
DAMMIT Rob I was JUST scrollin down here to type this!!!

Rings spring OUTWARDS against the cylinder wall. There is SPACE (however slight) between the inner side of the ring and the bottom of the ring groove, in the save manner that there is a tiny clearance between the ring and the sides of the groove.
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LOL. My bad. As they say nowadays.
 
RustyRatRod said:
Pistons ain't got a THING to do with whether you file fit. That's all dependent on the finished bore size.
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Never said they did... I was answering the OP's question/comment about piston size and fitting each piston to a certain bore because of various piston sizes in a set.
 
Krooser said:
Never said they did... I was answering the OP's question/comment about piston size and fitting each piston to a certain bore because of various piston sizes in a set.
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Ok gotchya. And along those lines, I am still old school when it comes to boring. I want my shop to mic a piston, bore a hole mark that piston for that hole and repeat.
 
only way to do it rusty- agree
never bore- well maby bore but not hone without pistons in hand
not agreeing that piston brand does not indicate that file fit is required
do not like my head jerked off
 
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