E12-80 ?'s

[Weasel73240Z]

I found a 79 280ZX in a local boneyard. It has the E12-80 dizzy that I want to install this winter to upgrade from my original points ignition. The car has been sitting without running for about 12 years. The owner of the yard (who I've know for my whole life) says the car was driven to the spot that its sitting in. Any concerns with these dizzy's "going bad" from sitting too long? Also, can I use my existing coil/ballast resistor set-up with the ZX dizzy, or should I buy a new one meant for the E12-80 ignition?

I know this isn't electrical, but.......

The parts car also has a 5-speed that I'm thinking about buying. Its a NA 1979 280ZX. I don't think this is one of the really desirable Borg-Warner tranny's, but if I can pick it up reasonable, it would still be a major upgrade over my original 4-speed, correct?

BTW, I am planning on doing a rear diff. swap this winter also, to either a 3.70 or 3.90, so I need to do the 5 speed swap. So do you think I should wait for a BW 5-speed to come along, or go with the one in the parts car?

[a7dz]

Paul;

Make sure you get the base from the ZX. It is different then your points dizzy.

[Arne]

Dizzy - I think I'd want to disassemble it for cleaning and lubing, and also to make certain that the bearings under the base plate are still good. Other than that, it should be OK.

Also, there is no need to use the ballast resistor with this ignition, you should bypass it instead. No harm in using the stock coil, although a generic aftermarket coil to ZX specs may provide a touch hotter spark, and shouldn't cost more than $15-20 for brand new.

Trans - I see no significant benefit to using the BW T5 for a mostly stock 240Z. The ratios might be a touch better, but not enough to worry over for normal use. The 5 speed from the ZX will be a very simple bolt-in for your car, whereas there are several mods needed to install the T5. I'd take that ZX 'box as long as you can get it affordably enough, and have some assurance that it's in decent shape.

[jmortensen]

The ZX distributors won't "go bad" from sitting in my experience. There are two common problems with them in my experience. 1. The vacuum advance goes bad. This is true of every ZX distributor I've seen, except one. So you can plan on fixing that if you want the vacuum advance to work. 2. Much less common is the module going bad. They do go bad from time to time and they are relatively expensive to get a new Nissan unit. Your options are to get a new one or to wire the distributor to use a different module, like the GM HEI. I have the general impression that the HEI tends to go out with more frequency, but you can get a new one at any corner auto parts store for $20.

On the trans I think the BW trans is the wrong way to go, especially if you don't have a turbo. It MAY be marginally stronger, depending on who you ask, but it has very wide gear ratios. The 80-83 NA ZX 5 speeds have much closer ratios, which is a lot better for performance driving use. Of course, you really need the diff to take advantage here, because if you get the tall 1st gear and have a tall rear end, you're going to end up slow off the line. I like a 3.90 with the later 5 speed (that's what the ZX's came with) or a 4.11. I had a 3.70 with this combo in my car for years, it did fine, but it was noticeably tall to me and gave a theoretical top speed of 170+ mph, which wasn't going to happen in my car unless it was dropped out of an airplane.

Distributor rebuild info:

http://www.jrdemers.com/280ZX/distributor/distributor.html

[EScanlon]

I've heard that the ZX dizzy works best with the ZX coil... don't know the difference involved just that it was a recommended swap also. My car came with the ZX dizzy already installed.

I've had one module go bad after being swapped from my car into another vehicle for testing purposes then returned to my car, but only after a 60 mile drive. (Just as I was entering the Canby Fairground for the Canby show.... talk about embarassing!) The module was 7 + years old (I bought the car in 01). Thanks to Arne who rescued me, I was able to get home.

FWIW

E

[zbane]

I think I'd want to disassemble it for cleaning and lubing, and also to make certain that the bearings under the base plate are still good. Other than that, it should be OK.

Just be sure to use care when disassembling the dizzy-the magnetic ring (pictured) is fragile.

Also, if it's been sitting for a while, don't plan on just opening it up. You will most likely have to hit it with penetrating fluid and let it work for a bit...

[blue 72]

I've also got a '79 ZX dizzy on my car. It is pretty simple and straightforward as long as you can follow the instructions which are available on a few sites. As far as coils go, most people put a hotter coil on to take advantage of the electronic distributor not using a ballast resistor, so it takes a full 12 volts all the time. The cars with non electronic coils only provide 12 volts on startup, while the rest of the time they were choked down with the ballast resistor.

I too have had an E12-80 unit go out on me. Luckily it was a progressive failure, and I was able to limp it home. Now I carry two spares in my glovebox. I've currently got an E12-93 module running mine. Everyone says they aren't worth anything, but they just don't know how to wire them correctly.

I've got a local junkyard with 3 E12-80 modules still in cars that I'm going to pluck next time I'm out that way. You never know when they might come in handy.

[jmortensen]

I too have had an E12-80 unit go out on me. Luckily it was a progressive failure, and I was able to limp it home. Now I carry two spares in my glovebox. I've currently got an E12-93 module running mine. Everyone says they aren't worth anything, but they just don't know how to wire them correctly.

Is there a way to wire them so that they don't pull timing out? That is the issue with them...

[blue 72]

The progressive failure apparently is not an uncommon thing when these let go. They shut the car off, but after letting it sit for a minute, the car starts back up and runs a while before dying again.

When that happened to me, I went to a junkyard to find a replacement. Luck wasn't with me that day, so I grabbed a couple of E12-93 modules from some later ZX or Maxima junkers.

Upon returning home, I realized my mistake, but didn't feel like doing any more junkyard scrounging immediately. I started some extensive web searching instead.

I had tried simply installing the module in place of the E12-80, but the timing retarded quite a bit. No amount of timing adjustment (turning the distributor body) would get the car to run like it should.

Based on the experiences of some members over on the HybridZ boards, and reading from a few other web sites, I found out what those little prongs on the side of the E12-92/3 ignition modules are for.

For example, let's quote Bryan Little (http://www.datsunzgarage.com/engine) for a second.

* E12-80 1 top plug (2 terminals). Used on 1979-7/81 ZX, Maximas, B210.

This module works best on carbureted motors. The dwell curve is preset into the module, it only needs the distributor and coil to function.

* E12-92 1 top plug, 1 side plug. Used on 8/81-83 ZX's, Maximas.

I found when using a E12-92 in place of a E12-80 it automatically retarded the timing 8 degrees. Even setting the time up 8 degrees made my engine feel sluggish, so I don't recommend it on carbureted motors. According to the shop manual, the 2nd plug on the side is for a spark advance signal from the brain and other sensors. Some claim this module is identical to the E12-80. Not on my engine unfortunately.

"Okay, so substituting an E12-92 or E1-93 module pulls off timing, but the prongs on the side get signal from the computer to advance timing? Right? Did I read that correctly?" I thought to myself.

Easy enough to theorize what happened next. All I had to do was run a wire with 12 volts (spliced from positive post on coil) to one of the pins on the side of the E12-93 module, and gained back 5º of timing (iirc). It's wired to the I pin, but the W pin does the same thing.

After that, I simply adjusted the distributor to give me 18º btdc @ idle, and it has run flawlessly for over 1,500 miles. Pulls cleanly to 8K RPM too (although I do have the head and cam to make it there).

Well, there you have it. Now anyone can run the E12-92 or E12-93 modules which have been completely worthless up until now.

Edited October 6, 2008 by blue 72

[jmortensen]

If that works then good job.