> That is a good trick Paul, I will remember that one.
 > Regards Don

 I think it was Lynn Hanover that came up with this.

 Paul Lamar

    It is a piece of brake line tubing soldered into a spark plug shell. The
small diameter plastic hose (from Sears) gives a dramatic read up and down
over TDC.
I believe that the front rotor on a 20B looks the same as the front rotor on
a 13B, so
putting a 20B pulley on a 13B that has been parked at TDC and marking the 20B
pulley using the 13B pointer as a guide should work. Also, the spark plug
holes are about equally displaced about the center of the rotor at TDC. You
can look into the empty plug hole for leading and turn the engine until you
see an apex seal in the center of the hole. Make a removable mark on the
pulley under the pointer. Keep rotating the engine until the next apex seal
appears in the center of the trailing hole. Make another removable mark on
the pulley. Half way between the two marks it TDC.

Do this several times making temporary marks for TDC. Once you are confident
you have done it correctly, mark TDC on the pulley with a file and fill the
notch with white paint. Mark your "timing" position, 20- 24-26 whatever you
plan to run the same way but with red or orange paint.  Measure the pulley
diameter exactly. Use C=3.1416 X Diameter to determine degrees per inch, for
how far along the edge of the pulley to mark off the points you want. I have
TDC and 24 degrees marked on mine. On a 12A 24-27 degrees is good up to 9,500
RPMs. Unless it is boosted in some way there is little you can do with timing
that will hurt it as long as it is below 30 degrees total. The 13B and 20B
have more volume to get burning, so maybe 22-24 degrees would be fine at the
lower revs.
I ran 20 degrees for years with no damage. Now I run 27+ with no damage on 89
Octane pump gas.
Lynn E. Hanover

 
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