SEAL IN THE POWER continued

 

    I HAVE USED THEM IN THE PAST AND AM IN THE ENGINE SHOWED IN THIS ARTICLE. .A COUPLE OF THINGS TO NOTE IS TRADITIONAL COMPRESSION PISTON RINGS ARE ONE PIECE.  THE TOP COMPRESSION RING TAKES THE MOST BEATING AS IT IS CLOSEST TO THE EXPLOSION. A SMALL AMOUNT OF GAS WILL TRAVEL THROUGH THE RING GAP THIS WILL ALSO HELP TO KEEP THE RING SEATED AND THEN IT COMES TO THE SECOND RING .THE SECOND RING IS ALSO A COMPRESSION RING AND WE DO NOT WANT COMPRESSION GOING BY THIS RING. THAT IS WHERE THE TWO PIECE TOTAL SEAL RING COMES IN, IT ELIMINATES THE GAP AND SEALS THE COMBUSTION. THE LOWER RING IS THE OIL RING AND IS MADE UP OF THREE PIECES. THE EXPANDER AND THE UPPER AND LOWER SCRAPER. THEIR JOB IS TO KEEP EXCESSIVE OIL FROM GETTING TO THE TOP END.

    DEPENDING ON WHAT TYPE OF PISTONS YOU ARE USING FOLLOW THE MANUFACTURERS INSTRUCTIONS FOR PISTON TO WALL CLEARANCE IN THIS CASE WE CHOSE .002. THE BORE OF THE CYLINDER DETERMINES THE RING GAP. THE STANDARDS SET BY THE SOCIETY OF AMERICAN ENGINEERS IS .010 TO .020  FOR A BORE OF 3 TO 3 31/32.FOR A BIG TWIN WITH 3-5/8 BORE I USED .012  

    THE PROCEDURE FOR HONING THE CYLINDERS IS CRITICAL TO MAKING RINGS SEAL

    FOR CLARIFICATION I AM WORKING ON AN 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

     PISTONS ARE MEASURED AT THE BOTTOM OF THE PISTON SKIRT AND MEASUREMENTS RECORDED .A DIAL BORE GAUGE IS SET UP AND THE CYLINDER IS CHECKED DEPENDING ON WHAT YOU ARE USING THERE IS A SLIGHT DIFFERENCE IN PROCEDURE WHEN HONING TO OVERSIZE START WITH A BORING BAR OR 70 GRIT STONE TAKE IT OUT TO .003 OF THE SIZE YOU WANT .WITH A 280 GRIT STONE BRING TO JUST UNDER YOUR FINAL SIZE. NEW CYLINDERS SKIP THE 70 GRIT STONE.  FINAL HONE IS DONE WITH A 600 GRIT CORK ABRASIVE STONE LETTING THE CYLINDERS COOL PERIODICALLY TO CHECK SHAPE AND SIZE.

    I LIKE SUNNENS HONING OIL AND A 60 DEGREE CROSSHATCH (OFF VERTICAL) AS I FEEL IT DOES A BETTER JOB OF KEEPING THE OIL WHERE I WANT IT TO BE. UNLESS A FINE GRIT HONE IS USED IT IS POSSIBLE FOR SOME OF THE CRANKCASE PRESSURE TO TRAVEL UP THROUGH THE CROSSHATCH SCRATCHES BETWEEN THE RINGS AND CYLINDER WALLS.

    CLEAN AND DRY ALL PARTS THOROUGHLY.  INSTALL RING IN CYLINDER A EQUAL SPACE FROM THE TOP.  CHECK GAP AND FILE IF NECESSARY.  IF YOU HAVE TO FILE RINGS GRIND OR FILE FROM THE OUTSIDE TOWARDS THE INSIDE.  FINISH WITH CROCUS CLOTH .ONCE CHECKED MAKE SURE THAT RING STAYS WITH THAT CYLINDER. ALSO BE SURE NOT TO MIX OR EXCHANGE OIL RING RAILS WITH RAIL IN TOTAL SEAL RING.

    FOR TOP RING INSTALL DOT SIDE UP OR UNMARKED RINGS WITH INNER BEVEL, BEVEL SIDE UP.

    FOR GAPLESS TOTAL SEAL RING INSTALLED IN GROOVE # 2 INSTALL MACHINED RING FIRST WITH GROOVE SIDE DOWN AND GAP 180 DEGREES FROM TOP RING END GAP.

 

 

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