[Healeys] Static Timing a Pertronix Ignitor
bspidell at comcast.net
Sun Feb 12 13:18:31 MST 2017
"... The vacuum advance/retard, if fitted, is only in operation at low
This is something I've wondered about. This is true for 'manifold'
vacuum, but the vacuum pickup off a Healey's SU carbs is near the
throttle, which I believe is called 'port' vacuum. If my knowledge of
Bournelli is correct, this vacuum is created by air moving over the
port, and increases with airflow.
On 2/12/2017 9:15 AM, Oudesluys wrote:
> Not quite, setting the static timing was the only means at the time
> and the instructions should be accurate. Nowadays it is more
> convenient to set the timing dynamically, but without vacuum and at
> stationary revs, which is in most cases the same as the static timing.
> The so called fine tuning is in practice irrelevant except when the
> car is tuned on a rolling road. However you can check if the
> centrifugal advance mechanism is working properly by keeping the
> engine on e.g. 2500 or 3000rpm and check what advance is indicated.
> Disconnect the vacuum line for this though. The vacuum advance/retard,
> if fitted, is only in operation at low load.
> Kees Oudesluijs
> Op 12-2-2017 om 12:51 schreef Simon Lachlan:
>> In this instance, static timing would precede dynamic timing because
>> the car was so far out of tune that the engine would not run.
>> In my thinking, static is only used to get the timing onto the right
>> map page, enabling the engine to be started and then tuned more
>> precisely by other means.
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