MSD 6A with points?

[Stanley]

Anyone using MSD 6A or 6AL with points? Searched all the posts, lots of threads (problems) about hooking it up to 280zx distributor, Unilites, Pertronics, but found nothing useful about using it with points. So either it's impossible, or seems too difficult, or it's so easy nobody bothered to post a question.

My '73 240 has stock Euro distributor and stock wiring including a regulator. The tach wires to + terminal on coil (distributor wire is only thing on - side), so if I understand, it's a current triggered tach (9/72 build). I counted 6 wires on the tach so maybe it's a 4-wire (!) if that matters which I doubt. Anyway according to the instructions, it needs a Chrysler ballast (instructions:"The additional resistance may correct tachometer function"). Don't like that "may". There's a diagram of that that's confusing to me (which wires go where) on pages 2 & 3.MSD 6A misc.pdf

Here's a PDF, shot of my tach and stuff compiled from the instructions that might be relevant.

Photos might help, especially how that ballast is hooked up.

[madkaw]

There are folks that sell a unit that transforms the tach to a voltage type. It's a plug and play and necessary for you to use the MSD. I am trying to have a new CB board built for my tach to do the same thing.

Why are you so worried about keeping points. Get rid of them and go pertronix or something.

Edited April 20, 2014 by madkaw

[Zed Head]

I think that he wants to go directly to electronic with the least amount of fuss. The MSD option would be great if the tachometer problem didn't exist. No load on the points to wear them out, reliable points trigger with a reliable electronic ignition. Pertronix modules have their own issues, like burning out if you leave the key on. If he switches to an electronic distributor then he has to get in to advance curves.

It's surprising that MSD doesn't put a little effort in to clearing up the tach issue. I'd guess though, that people that developed the product are long gone and those that are thee now just repeat what the instructions say.

What's wrong with your tach operation that you need to develop a circuit board?

[Stanley]

Least amount of fuss, exactly. Also least amount of money. I get the 6A box for $180, free shipping, which I can do, anything else not at this time. Recently invested in three sets of genuine Nissan points, and my distributor is almost new. Have a small-port, higher compression (than stock) head that puts my shift points for quickest runs under 5300 rpm. Even if I put a cam and headers I doubt if I'll be shifting over 6000 so I think points will be OK. Not a race car anyway, just like how it goes when it winds up.

Saw a similar question about MSD/points, posted by Conedodger, wonder if that worked out.

[madkaw]

from a quick search you need the 8920 tach adapter to make that work

[madkaw]

This is what I want to do to drive my MS3

http://www.classiczcars.com/forums/electrical-s30/36969-converting-four-wire-tacho-current-driven-electronic-tacho.html

[Stanley]

From my reading and re-reading, that could still be wrong, 8920 tach adapter is for magnetic pickup distributors, 8910 adapter is for voltage triggered tach (some early or later Z's?). For the current driven tach like my early 73 it says use Chrysler ballast that "May" work. Don't want to pay $180 until I know if it can work or not. Datsun gets me to work and back so I can't sit around pretending and hoping I know what I'm doing if I don't.

Sounds like that electronic conversion would work though. $6 parts sounds OK. Might need some circuit board experience, though.

Edited April 21, 2014 by Stanley

[63ronin]

Ya know, I have a '78 280Z with an MSD-6A (running a Holley 4bbl rather than the original FI). Haven't been able to get the tach to work yet. Tried just about every wiring config I could come up with. And that includes using the MSD 8920. Under the dash there is a resistor. According to the manual wire used to come from the coil (- terminal?), through the resistor, onto the tach. I got my meter out to check the resistor. All I get is an open circuit. Wondering if I damaged the resistor in all my mucking about.

I installed the MSd ignition as shown in instruction for "Installing to an MSD Distributor/Crank Trigger" (second image on page 10). Car runs fine. Just have no tach...

I haven't actually looked, but my manual says there are three wires going to the tach (not including two for the light). These should be power, ground, and signal.

Edited May 3, 2014 by 63ronin