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Re: Pertronix interfering with tach?

To: "Chris Masucci" <sooch@houston.rr.com>
Subject: Re: Pertronix interfering with tach?
From: "Alan Seigrist Blue 100" <healey.nut@gmail.com>
Date: Sat, 15 Apr 2006 00:04:18 +0800
Chris / Michael -

Points actually don't change the level of current through the wire,
but they will spike the pulse a little more dramatically than with a
Pertronix.

That being said, the fact that you've added a Pertronix should not
make a difference to the draw of net current through the ignition
wire, as at the end of the day, the pulsing current will be the same
to fire a plug.  I put a pertronix on my BJ8 and did not have to
adjust anything... the tach is accurate.

The real culprit is more likely that along the circuit on the white
wire between the ignition switch (through the back of the tach) to the
coil there is corrosion and poor connections with the spade
connectors.  (With the dramatic current pulse that points will make,
it can overcome the corrosion and drive the tach, but with a Pertronix
it will lessen).

This white wire draws more current than any other wire in the whole
car, and as a result the connections between the wire and the spade
connectors often get corroded over time... esp. on factory harnesses
that use aluminum wire.

I would highly recommend that each connector on the wire is removed,
and then soldered back on with a very strong solid connection.  If you
leave the wire as is you may be flirting with disaster... corroded
connectors can get hot and melt the wire (or let the smoke out as they
say).  You can check this by feeling the connector on the back of the
ignition switch after you've run the car for a while, if it is hot,
that is your problem.

Good Luck!

Alan

'53 BN1 '64 BJ8


On 4/14/06, Chris Masucci <sooch@houston.rr.com> wrote:
> The pertronix draws less current through the white wire looped behind the
> tach than the points did.  Less current, smaller magnetic field, smaller
> current on the transformer secondary winding (inside the tach).  Must
> increase the field.  Add an additional loop or two to the loop at the back
> of the tach.
>
> Cheers,
> Chris
> BJ8
> ----- Original Message -----
> From: <Awgertoo@aol.com>
> To: <healeys@autox.team.net>
> Sent: Thursday, April 13, 2006 8:20 PM
> Subject: Pertronix interfering with tach?
>
>
> > I'm posting this for a friend of mine who is not a subscriber but
> > described
> > an interesting situation to me--he says that about the same time he
> > installed a
> > Pertronix unit on his BJ8 his tach started to indicate about 20% low,
> > apparently at all speeds.
> >
> > Does anyone have any experience or suggestions here?
> >
> > Best--Michael Oritt




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