280zx Distributor Upgrade (240z)

[madkaw]

My 9/71 has a current driven tach like yours. The only wire that came from the car was the old hot dizzy wire. I had the original plug in for the matchbox. You don't need any of that condenser crap. 

I used the coil recommended for the zx dizzy, not sure of ohms. 

 

[siteunseen]

Google Crane PS20 for the coil. That was most recommended by other forum members when I did mine. I think it's 1.5 ohms, works great compared to the yellow brand I had on another car. It overheated and leaked oil in a few months. You'll need a zx cap and button, they're bigger. You will have a larger plug gap also.

I bought all my stuff from amazon.com, best prices at the time.

[Chickenman]

^ Crane Ignition products X2. Much better quality than MSD. Crane ignition boxes ( or anything else ) rarely fail.

[Namerow]

As I understand it, the use of a capacitor (aka 'condensor') in points-type ignition systems is not dictated by tachometer issues -- although it can create them.  The capacitor is there to store the electrical energy that's generated in the ignition coil's primary (12V) circuit when the points open and the electromagnetic field around the coil's windings begins to collapse.  That collapsing electromagnetic field generates a reverse-direction current in the primary circuit -- a process called 'self-induction'.  The capacitor is there to absorb this electrical energy.  Without it, a heavy electric arc would occur across the separating/closing contact points, resulting in pitting and burning of the points surfaces.  The capacitor dumps its stored energy back into the primary circuit when the points are actually closed. 

A nice side-benefit of the points capacitor is that it eliminates/reduces the 'noise' that the car's radio can pick up when points arcing takes place.  I'm not sure whether that 'noise' is electric (travels in the wiring), electromagnetic (travels in the air), or a combination of both.

Unfortunately, it appears that the cyclic energy storage/dumping action by the capacitor interferes with the ability of some electric tachometers to see a proper signal.  You'd need an oscilloscope, I suppose, to be able to study the difference in the shape of the signal, with and without the points capacitor in place. 

Our absent friend, Blue, did a nice write-up a couple of years ago on how to swap a later-generation Z tach into an early car.

[Zed Head]

7 hours ago, Namerow said:

As I understand it, the use of a capacitor (aka 'condensor') in points-type ignition systems is not dictated by tachometer issues -- although it can create them. 

I was just pointing out something real that happened.  Always nice to get one or two of those.  In my case, the capacitor fixed a problem.  When the wire to the capacitor fatigued and broke the problem came back, so it's been verified twice. No capacitor on the coil negative, no tachometer function.  Someday I might move the capacitor to another spot just to see how important location is.  I can't explain it but it's a real thing.  But I can't explain how my tachometer works either, or how injector pulse durations are controlled.

If you search "Kettering ignition" you can read all about how capacitors made their way in to points-style ignition systems, and the multiple benefits they have there.  Seems like they started out for contact durability, then either the second benefit was a bonus or some electrical wizard did some complex math.  Or both, who knows.  There are some fascinating writeups out there..  That Kettering guy was pretty smart.

The electronic ignition cars still came with capacitors on the alternators, so it's not just a points thing.  Maybe they're insurance against a failing sparky alternator, maybe alternators inherently generate RF interference.  I don't know, but the capacitors are there.

[Namerow]

If you're interested in the history of the industry, 'Boss' Kettering's biography makes an interesting read. 

One other component of the capacitor story that adds uncertainty is the report that the foil-in-a-can designs used for automotive applications apparently have a shelf life and lose their effectiveness over time. So that shiny new replacement that's been sitting on a shelf in a warehouse or parts-store for years may no longer be 100% effective.  Or so I've read.

[Kurbycar32]

On 2/13/2016 at 7:00 AM, Namerow said:

Our absent friend, Blue, did a nice write-up a couple of years ago on how to swap a later-generation Z tach into an early car.

What happened to Blue?

[siteunseen]

4 hours ago, Kurbycar32 said:

What happened to Blue?

Nothing! He's alive and well, with a wonderful wife and daughter in college,  he has a life too.

Cliff

[Walter Moore]

I used an ignition coil for a ZX with my ZX distributor. It didn't seem that complicated, just bypass the resistor and take the wires that went to the points to the ignition module. I will have to check my notes again.

 

[CDL1542]

Looks like my e12-80 matchbox is fried on my ZX distributor. To the Stroker guys out there: Should I go with another ZX one or is there something better I can go with? Thanks!

[Chickenman]

The E-12-80 Module is pretty powerful. I know of Turbo cars running them at 15+ lbs boost. Unless you need the Rev limiter, or other features like Two Step or Boost retard,  there is really no need to got to an MSD or Crane box.

[Zed Head]

On 3/19/2016 at 3:48 PM, CDL1542 said:

Looks like my e12-80 matchbox is fried on my ZX distributor. To the Stroker guys out there: Should I go with another ZX one or is there something better I can go with?'  Thanks!

"stroker" is irrelevant.  Unless you only want to talk to guys who have one. 

The ZX distributors have other weaknesses though.  Why do you think it's the module?  The stator magnets seem to break a lot, and they actually sell a replacement bushing for the dizzy shaft.