Early electronic tach query??

[nomad]

Can anyone tell me if a early electronic tach (65) that has had the polarity reversed will function correctly with a Pertronics distributor????
Tnx.


Kurt

 

[Sarastro]

This question comes up a lot, and while I have no direct experience, it seems that many people have trouble with these and the Pertronics.

The tachometers work by sensing the current pulse in the primary (low-voltage part) of the ignition circuit. However, the Pertronics almost certainly does not have a similar current pulse, if it has any at all. I suspect that's the problem.

 

[spritenut]

It works.

 

[Pythias]

I had to take one loop out

 

[dklawson]

More often than not... the RVI tachs do not work or they do not read accurately when connected to electronic ignitions. Even if you think your tach works, double check it against your tune-up equipment or an aftermarket tach.

 

[nomad]

Appreciate the comeback on this. Spritenut says they work, Doug and Steve probably not and Bill says modify so I am thinking stay with points or maybe get ahold of you guys when I fit the units.
Thanks.

Kurt.

 

[dklawson]

You can always try the tach. I know of at least two people who have had no problems fitting an RVI with Pertronics and you may be equally fortunate. However, if the tach worked with points (but stops working when you fit electronic ignition) I would not try anything more than adjusting the number of wire loops on the back of the tach to get the gauge working. Spending more time and money beyond that will not likely be productive or economical. Later RVC type Smiths tachs use a single wire hookup to coil (-) and they are compatible with electronic ignitions.

 

[Pythias]

It may also help to drill a hole in the case right behind the potentiometer. That way you can adjust it if its off a little without removing it from the dash.

As an aside, my tach is in need of a rebuild as it reads differently depending upon ambient temperature. I use the hole to sometimes adjust the tach as I drive, matching rpm to match mph (calculated)

 

[nomad]

Bill, I remember visiting with you about your tach at LoTO and afterward. I did drill a hole in one to fit to my 65 stock since the original is way off. Did'nt fit it though. Don't know if I'm coordinated enough to adjust on the go!! What I'm wondering about is if I can make one work with a Datsun "matchbox" dizzy. They are hall effect like the pertronics. Looks like I'll try it or go to a points dizzy which would'nt be hard.
Thanks again,
Kurt.

 

[dklawson]

if I can make one work with a Datsun "matchbox" dizzy. They are hall effect like the pertronics.

Do you perhaps mean the Hitachi dizzy from the 1.6L inline Nissan four cylinders?