[SEL] TWO THREADS

[bill at antique-engines.com]

As a degreed mechanic who has held various certifications on small engine
repair and was an authorized warranty repair person for various brands
back in the 70s - and as a professional auto mechanic - it's pretty easy
to comment on the valve issue.
Valve timing is a science - just ask those who have cams custom ground for
specific needs for performance, etc. There are grinds for performance in
general, for top end performance, and for low-end torque or grunt. There
are grinds for more MPG as well.
Valve timing will vary from engine to engine, maker to maker. You need to
follow the *Manufacturer's recommendations* for the most part, unless you
know what you are doing. Otherwise the side effects can be:
Lower dynamic compression - or even higher dynamic compression (NOT
talking about "static compression)
or
You can shift the power band up or down depending on which way you shift
the valve opening and closing, valve overlap, etc.
You can impact idle - make it so it won't idle worth a crap, or have a
"rough idle".
There's opening angle, closing angle, lobe separation, lift, ramp
acceleration, and more......

Do not second guess them unless you know what the heck you are doing.
Yeah, this applies to antiques as well as modern Honda engines running at
10,000 RPM.

for magnets.....
Vibrations do assist in the "lining up" of the poles on the molecular
structure while charging.
You do need to get as strong a field as possible, a weak charger means the
magnets won't reach their full potential no matter how hard you bang on
them or how long or many times you charge them.
More winds, more power through the windings means more magnetic strength.
This translates into better charged magnets. Yes, a weak lame charger can
charge a dead magnet so it may work, but it won't be good.
Weak magnets mean weak spark.
There's a science to this..... and a lot of very good web sites on this
issue - some of the best ones are AIRCRAFT related...... (wonder why they
are so concerned about good magnet strength?? I don't get that....)
Sort of like auto ignition coils - more power through the windings longer
means the lines of force are stronger, and when the collapse, you get more
output. So you need the strongest magnets you can get - this means you
need a strong charger.

The younger guys are "shade-treers" and didn't pay attention in their
science classes, IMO.

> 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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