File to Fit Piston Rings

Engine, Transmission & Driveline

  1. Dylan Galvin

    Dylan Galvin Active Member

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    I’m putting together the 496 (383 stroker) and I’ve got a couple questions.

    The total seal c9190 65 rings are ‘file to fit’ and I’m wondering what clearance you guys think I should go for. It’s a street car, will be a very mild cam, -20 dish pistons.

    Another question, do I only file the top ring or also the lower one?

    thanks in advance
     
  2. commando1

    commando1 Old Man With a Hat on the Porch FCBO Gold Member

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    Here you go...

    Screenshot_20200705_173054.jpg
     
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  3. Dylan Galvin

    Dylan Galvin Active Member

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  4. Big_John

    Big_John Illegitimi non carborundum FCBO Gold Member

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    Depend on the pistons... The Keith Black Hypertecitic (or whatever they are) will need a different (wider) gap than a cast or forged piston.
     
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  5. CBODY67

    CBODY67 Old Man with a Hat

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    The gap on ALL rings should be verified as correct. My machine shop operative uses a tool to square the ring in the newly-honed bore, about 1.5" into the bore, then a feeler gauge to check the gap. If it's not wide enough, then he uses a "ring end gap filer" mechanism to carefully file the ring's ends. Then retry the ring in the bore. Can take a while to get EACH ring "right", by observation.

    It was noted on an Engine Masters segment, when they were seeing how much boost a stock Chevy 350 could take, that one reason boosted engines suffer piston failures is that as the boost is increased, the rings heat up and expand to close the gap. When that happens, the life of the piston's crown is compromised, basically cutting it from the piston skirt. So, the particular engine's rings had a wider gap than a non-boosted engine would have had. FWIW

    Enjoy!
    CBODY67
     
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  6. PH27L7

    PH27L7 Active Member

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    My recommendation is to always follow the ring mfg's instructions regarding ring gap. Those are conservative numbers and some engine builders may go tighter based on personal experience to get the last HP out of an engine but not needed in your case. On file fit rings you will always need to gap both top rings. The oil rings should need nothing but gap should be verified. As with any job, good tools make the job much easier & faster.
     
  7. Cazman

    Cazman Active Member FCBO Gold Member

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    My file to fit rings came with instructions for bottom and top. I used my table saw to file them - not what you think.

    I had some adhesive backed disk sandpaper and I adhered that sandpaper to the face of my saw blade. With the power disconnected, I grabbed the belt that goes from the blade axle to the motor to turn the blade/sandpaper by hand while sanding the ring gap. I did this because it is not so easy to make a square file cut without a nice right angle tool and platform. Hence, why they sell a special file tool for this.
     
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  8. Dylan Galvin

    Dylan Galvin Active Member

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    Yeah my rings didn’t have instructions and I can’t find any, I have a ring filer
     
  9. Cazman

    Cazman Active Member FCBO Gold Member

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    I would call Total Seal
     
  10. stubs300

    stubs300 Senior Member

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    Yeah, it's called a upside down piston stuffed in the bore!
     
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