Andy; the latest type rotor has the extended brass contact arm to
compensate for this exact problem, while some vendors continue to use
the small width arm which works fine as long as housing alignment is
close to proper clock angle.
John; Number one cyl is at the front of the engine.
Your "plain" pulley has only a single notch and this is aligned
against the steel marker tab welded to the timing gear cover. Later
models used a "harmonic balancer" type pulley combo which has the
heavy thick steel wheel . This device has lots of lines, representing
5 deg. increments.
Timing covers have only a single pointer and when the "plain"pulley
with the single notch is aligned, this represents 0 deg. TDC. The
mechanic has to place a chalk or paint mark on the pulley ABOVE (or
ahead of) the pulley notch to thereby represent degrees BTDC (before
top dead center) as desired. From that notch, 6mm = 5 deg ; 9mm = 7
deg ; 10mm = 8 deg ; 12mm = 10 deg. (and etc. all the way up to 36
deg if you care to do it.). Later model "plain" pulleys did have
notches on the rim going up to 30 deg.
I would say that in view of the potential danger of engine damage,
as well as the potential better hp gains obtained from KNOWING your
exact timing setting, you should make permanent notches on your
pulley, for future tuning use !
The New York City importer for the USA, worked with me back in the
60s to agree to permit the following procedure to be published, and
it is as follows:
Set timing gradually more advanced and keep clocking the acceleration
of the car in 4th gear , 20-50mph.
Knocking sounds must NOT be permitted.
When you have obtained the timing advance which gave the quickest
accel. times, reduce the timing advance to see if the accel remains
the same with less advance setting. The idea here is to find the
fastest 20-50 accel in 4th gear BUT with the least amount of timing
advance.
FYI, turning the knurled nut on the dist. advance device (octane
setting knob?) one full turn, changes timing by 3.0 degrees , either
advance or retard, according to your direction of turning.
This is a nice bit of data and if you happen get some El-Cheepo fuel
and hear knocking, you can retard , say one turn and once the fuel is
used up, reset to original position again.
Dick T.
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