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Posted: Thu Oct 12, 2017 5:56 pm
by Sideways
1970 cortina GT wrote:Old, topic but I have another question. Once I have converted my tacho to negative earth is there anything else I need to do to it if I'm using a Petronix electronic ignition? There is a place in NY called Nisonger that suggests there are some other changes necessary? They are looking at $275 US to do the conversion, appreciate your thoughts anyone. BTW I ran an Accuspark electronic ignition in my MK2 and whilst it is negative earth I didn't change anything else in the tacho.
I (vaguely) remember doing the conversion on a '66 Elan as well as a couple of Lotus Cortinas, both '65s and don't remember doing anything with the rev counters to get them to work properly - and I drove using the rev counter back in those days, rarely looked at the speedo!
This
http://www.lotus-cortina.com/electric/convert.htm may help - never tried it myself but looks fine at first glance.
Posted: Fri Oct 13, 2017 2:12 pm
by 1970 cortina GT
Thanks guys, I've seen the positive to negative ground conversion details it's just the electronic ignition installation and associated possible changes to the tach that I was wondering about. Thanks.
Posted: Sat Oct 14, 2017 11:42 am
by Sideways
1970 cortina GT wrote:Thanks guys, I've seen the positive to negative ground conversion details it's just the electronic ignition installation and associated possible changes to the tach that I was wondering about. Thanks.
Small correction to my previous post, I
did have an rev counter issue with a Plus 2 did I did the conversion on but that had an early MSD...I think the information to allow an easy (cheap) conversion is out there, just a question of finding it.
Posted: Sat Oct 14, 2017 12:51 pm
by peteleo
Lee,
Electronic ignition won't effect the operation of tach after converting the tach to -grd.
If using MSD you will need to install a tach adapter ( made by MSD Inc. ).