<VV> Re: Pertronix and tach

[Padgett]

>  I just installed "Pertronix I" on a friends' car (65 140 HP -- 4 Carb). 
> The car
>   starts fine and idles nicely, however, when I check the dwell, it shows 
> 26 !
>   is that normal?
That sounds right - dwell is reduced at idle to limit the current through 
the coil which reduces coil heating. Unlike points, a TI can vary the 
dwell, increasing as the revs increase to maintain coil saturation. The 
secondary ignition system simply does not need much dwell at idle to 
maintain good spark.

>   Also, the RPM on a dwell meter shows 800 @ idle, however the
>    gauge on the dash (which was working fine before
>   pertronix) shows only 150 RPM !

that sounds like something wrong (probably an open diode) in the factory 
tachometer circuit. It may have been working before but are you certain it 
was accurate ? The Corsa tach uses a transistorized circuit (possibly 
because the long tach lead is too resistive for the standard parasitic 
tach) originally developed for use with the Delcotronic ignition. It should 
not care what the pulse source is. Of course if the tach is not original, 
all bets are off.

Padgett