*This message was transferred with a trial version of CommuniGate(tm) Pro*
HIYA Gavin!
It's actually quite elegant.
the wire running into the distributor is the voltage supply, it goes to one
side of the coil primary, and comes out the other side and goes to the
points, and thence to ground. Now, when the points open, the circuit in
the primary is broken and the field generated by the primary collapses
immediately, producing a much higher voltage (but less amperage) in the
secondary of the coil -this has many more windings than the primary so the
voltage induced is higher. this passes out the top of the coil through the
high tension lead to the distributor top, down through the rotor button, and
out the side of the rotor button to the spark plug needing the jolt. It goes
out the plug wire, crosses the gap at the plug, then to ground. Rotating
the body of the distributor changes the time when the points, open, either
sooner (advance) or later (retard) which is how you set the timing. Plus,
distributors have a mechanical spring mechanism that operates centrifically
to move the rotor advanced a little during higher RPM operation. Most MV
distributors don't have a vacuum can for spark control. It's usually called
a vacuum advance, but if I recall correctly, it actually operates by
retarding the spark under low vacuum load.....I'm fuzzy on that one, but it's
not an M151 related item. Oh, I forgot the condenser. Many folks think
it's for radio noise suppression, but that ain't so. It keeps the points
from arcing and burning excessively, and produces one big spark instead of a
lot of little ones in a row. That's oversimplified, but that's what it does.
Bad condensers kill points, or keep the motor from running.
I think that about covers it. Fellow OD motorheads, did I forget anything?
Mike in VA
This archive was generated by hypermail 2b29 : Mon May 01 2000 - 05:30:07 PDT