[SEL] TWO THREADS

William Young wmlyoung at yahoo.com
Mon Oct 19 03:53:36 PDT 2009


HI, GUYS   I'D LIKE TO GET SOME FEED BACK ON TWO TOPICS, VALVE TIMING AND MAGNET CHARGING.  I'LL START BY SAYING THAT MANY YEARS AGO I WORKED IN A SMALL-ENGINE REPAIR SHOP.  TO REASSEMBLE THESE  AIR-COOLED ENGINES ( BRIGGS, CLINTONS, TECUMSEHS, ETC ) THE VALVES WERE SET TO SIMULTANEOUSLY CLOSE( EX. ) AND OPEN (IN.)  AT TOP DEAD CENTER.  THIS IS NOT WHAT I HAVE SEEN ON DIAGRAMS ATTACHED TO LARGER JAPANESE ENGINES.  WHY THE DIFFERENCE?
   I'M NOW DOING A 7HP KUBOTA THAT HAS BEEN INACTIVE FOR MANY DECADES.  THUS FAR, I HAVE MATED THE FACTORY TIMING MARKS ON CRANK GEAR AND CAM GEAR.  NOT HAVING PRECISE TOOLS FOR MEASURING ANGLES, MY RULE OF THUMB ( ACTUALLY THE ANGLE BETWEEN FOREFINGER AND MIDDLE FINGER WHEN FULLY EXTENDED) IS TO HAVE EXHAUST VALVE START TO OPEN BEFORE BOTTOM DEAD CENTER AT ABOUT THE ABOVE ANGLE.  I CAN FINE-TUNE THIS BY ADJUSTING PUSH-ROD LENGTH.  VALVE CLOSURE IS DETERMINED BY CAM ACTION.
   IF I'M ON THE RIGHT TRACK SO FAR, PLEASE TELL ME SUITABLE PARAMETERS FOR INTAKE SETTINGS.  THIS ENGINE WILL NOT BE CALLED UPON TO DELIVER WORK;  MUSIC WILL BE ITS PRINCIPAL OUTPUT.  IT WILL NOT BE DELIBERATELY SLOW-TIMED TO HAVE COOLING WATER BOILING VIGOROUSLY -- AS SOME OF MY JAPANESE MATES LIKE TO DO.  GREAT FOR HARD BOILING EGGS.
    CORRECT ME IF I ERR ON THE FOLLOWING:  I HAVE BEEN TAUGHT THAT TO RE-MAGNETIZE A PERMANENT MAGNET A SATURATED FIELD IS REQUIRED -- LOTS OF AMPERE-TURNS, MANY, MANY GAUSS.  I SEE SOME MAGNET CHARGERS ADVERTISED SHOWING A SMALL, MICKEY MOUSE COIL AND A PUNY 6v. BATTERY.  THIS SUGGESTS THAT A FEW GAUSS, PERHAPS OVER A LONGER TIME, WILL DO THE TRICK.  COMMENTS PLEASE.
I HAVE HEARD OLD TIMERS STATE THE NEED FOR VIBRATION DURING THE PROCESS.  THE YOUNGER GUYS TEND TO SCOFF.  WHAT ARE THE FACTS?  ANY 
Ph. D.s OR E. E.s OUT THERE?
( Not the Piled higher and Deeper kind.)  BILL
wmyoung at juno.ocn.ne.jp 


      


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