> it working again. The car is completely different now. My vacumm
> advance unit is still not 100% but it does advance slightly. My
> guess is that at higher RPMs it is fully advanced as required but the
> snap acceleration doesn't create enough vacumm to compensate for the
Consider how advance works......
There's generally 2 systems. Vacuum in which the level of advance tracks
the amount of vacuum. There's are two states of high vacuum which of
course means there's 2 potential high advance states. At idle and barely
cracked throttle, the butterfly in the throttle is closed and vacuum is
high. Here, advance can be high as there's little load on the engine and
if retarded, the engine would run hotter. Once the vacuum goes down, you
want advance to more or less track RPM. Too much advance at low RPM/Low
Vacuum would be a throttle open trying to accelerate condition and with
too much throttle, pinging. So RPM is tracked to advance the timing. In
old engines, that'd be via centrifugal advance with weights/springs in
the distributor. These days, it's via "Motronic Magic" and the like where
that Mechanical Advance is adjusted by the Black Box "watching" the RPM
and doing that advance thing. At Crusing RPM, you'll have a little of
each type of advance in action to yield the most efficient power and thus
best mileage.
Maybe this will help you "advance" on the subject/problem!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jim Lill jpl@vectorbd.com
http://www.vectorbd.com/users/jpl
wa2zkd@wb2psi.#wny.usa.na