[Healeys] Static Timing a Pertronix Ignitor

Bob Spidell 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.

Please advise.


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.
>> Simon

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