Electronic ignition - Revisited after I gave up!

[Arne]

Like the title says, I've given up.

Over the past 2 years or so, I've wasted a pile of time trying to get electronic ignition into my 240Z. And I've failed. I could never get anything working well enough that I could be happy with it.

I've tried two different ZX distributors, a total of three different E12-80 modules, a Pertronix ignitor in the stock 240Z distributor, and four different coils (original 240Z, original ZX, new aftermarket ZX & 3.0Ω Pertronix).

It's worth noting that all three of the distributors I've tried had good vacuum advance units and no slop in the shaft bushings. Good, solid dizzies.

I've fought pinging from bad advance curves, ignition washout at higher revs, and sometime both. I've swapped plugs, wires, cap, rotor, etc. around several times in a concerted attempt to make this work. (It probably doesn't help my confidence in this knowing of at least three E12-80 failures in the past few years around these parts, either.)

Try as I might, I haven't been able to get anything to work as well and trouble-free as the stock points. I'm not an idiot, I've been working on and restoring old cars for decades. But I've certainly failed here.

Yes, I'll concede that a good electronic ignition should be superior to the stock points. But for a weekend GT touring car, the points are probably good enough.

I'll also concede that considering how many people have made this work on their cars, perhaps my car itself is at fault. (Perhaps too much voltage drop at the ignition?)

But on the other hand, there's plenty of threads here with people having issues with electronic ignition conversions, so maybe I'm not alone. At this point I'm not convinced that either the ZX ignition or the Pertronix are the answer. Maybe the Mallory Unilite is better, but that's too much money for a stock L24.

I'm still open to suggestions. I've got a Pertronix Ignitor and 3.0 Ω coil sitting on the bench right now. If someone can give me a clue, maybe I'll try again.

Or not. It's running great on the points right now....

Edited March 28, 2010 by Arne

[73 240Z Man]

Well, I am definately no expert, and I share your frustration when it comes to not understanding certain parts of the car, but I put in Pertronix into my 73 240 without a problem. Maybe its because I have so little experience so I followed the directions to a T, but it works great. No more problems with the points. I think you should give it another try. Pretend you are me and dont know what you are doing. I am happy with the Pertronix ignition.

IMHO, Chris

[Arne]

I think you should give it another try.

Done that, several times.

...so I followed the directions to a T...

Yup, analyzed and followed them carefully. More than once. It's a simple device, not much to screw up there.

No more problems with the points.

I guess that's part of the problem. I've never had any problems with points. They work great, better than the EI systems. Cars used points for decades. They are also simple devices.

[Mikez73]

Wow...I can relate to this .

At least you got yours to run. I can't figure out where I' going wrong. Like you said...it's so simple but...I can't even get spark.

If you're happy with points and don't feel any need to go electronic then by all means put the points dizzy back on.

I'm not giving up. Yet...

What was your reason for wanting electronic ignition?

[jmortensen]

I would suggest disconnecting the vacuum advance and running the car at about 18 degrees BTDC timing at idle and see how that floats your boat. I got really good mileage like that with SU's. Add MSD for even better mileage and you don't have to use the E12-80 module, just run the module built into the MSD.

The one thing I didn't see you mention is jumping the ballast resistor. It should run with the ballast in place but you'll get a lot hotter spark with it bridged. Having used both quite a bit (first Z had points) I wouldn't run a point distributor unless it was absolutely necessary.

[Bonzi Lon]

I will always run the points system on this car. It is the only system I know, its simple and it works. I thought about the change over during the refurbishment but it wasn't plug & play so it was out. Anything to do with wiring is out of my comfort zone.

Bonzi Lon

[alhbln]

Ignition setups can be quite frustrating at times to setup and debug, as those are the only electric circuits in a car (from the seventies at least) which depend on electric signals which change their state rapidly in a short timeframe.

Anything else, including an alternator, can be relatively easy checked and maintainted just using a multimeter or even a test light, but with ignition setups you need to take care of the different signals, voltage/current levels over the time and the timing of signals itself - which is something you can't really see just using an multimeter, so this, IMHO, is the main source of frustration when trying to find a fault in such a setup.

In an ideal world where you would have access to a distributor tester, scope and ideally a current clamp, finding a fault in a ignition system is quite straightforward and not that difficult if you have done it before, but most people maintaining their own car understandably don't have access to these tools.

Still, with a multimeter, spark tester, a digital timing light and a bit of patience you can find most issues, thats the good news! Happy to post general testing procedures if this is of interest.

Points are the simplest solution and the easiest to understand and to fix, if you are comfortable with the maintenance (setting dwell, advance weights etc). The only real limitation is the maximum primary coil current of ~4A and points floating at high RPM (typically starting at 4-5K). As Arne said, not a problem for a weekend GT. But for a high revving sports car this can be a real limitation to get maximum power and full combustion at each cycle. A badly maintained points based ignition setup with undersized wires or the wrong coil type will act as a rev limiter and lead to a sluggish throttle response when accelerating, even if your distributor advance curve is perfect.

A good transistor (electronic) ignition can handle up to 8A easily, so no ignition fading at high speed and with the more advanced constant current (e.g. dwell control) electronic ignition you'll have the base for a reliable combustion at any RPM, air temperature and fuel mix (if air, fuel and timing are ok). Transistor ignitions can be driven by points or magnetic/hall/optical triggers, the later setups adds timing precision but also complexity which can make it hard to find and fix faults.

The Pertronix Ignitor I conversion is quite handy as it integrates the contactless trigger and the transistor ignition in one small unit. Unfortunately, there is no current and dwell control (the type II and III is reported to have this), and depending on the coil you are using the outcome can be quite mixed. IMHO, the Ignitor I is a great unit for converting a non performance oriented car which revs up to 4-5K, but for a sports performance car (such as the 240Z) you might want to consider a different approach or use the Ignitor I as a trigger for an MSD 6A box.

My personal recommendation for a six cylinder engine performance ignition setup is a conversion based on the Lumenition Optronics optical pickup driving a Bosch 0 221 100 137 electronic ignition, this combination has no fading up to 9K RPM and is quite robust. I have installed this setup in quite a lot of cars over the last years, and none failed yet. As the parts are made in Europe they might be difficult to source in the US though.

IMHO, electronic ignitions are more complicated but quite worth the effort.

[reyzcon]

I've been working on Z's for quite a while now and just noticed that the 240Z dizzy #1 position is 60 degrees off compared to the 280Z's so when I switched from a petronix installed 240z dizzzy to a known good 280Z one I couldn't get the car to start till I removed the two scews that limit how far you can turn the dizzy and just turned it till I got it started but I also found my timing mark on the other side of the crankshaft did some research and read something about timing marks on air conditioned vehicles were on the oposite side of the crankshaft.I ended up repositioning my distributor drive to get my dizzy to point to #1 at TDC.If you compare a 240Z distributor cap to 280z you'll notice #1 on one is on the left of the clip and on the other it's on the right which is 60degrees off.I also tried moving my wires 1 post over but in my frustration decided to do it right starting off with everthing at TDC.Hope this helps you out.

[Arne]

What was your reason for wanting electronic ignition?

Just the standard things. Hotter spark, less need for choke, faster starts, and less maintenance. Nothing critical, and nothing that's worth the fussing around that I keep doing.

The one thing I didn't see you mention is jumping the ballast resistor. It should run with the ballast in place but you'll get a lot hotter spark with it bridged. Having used both quite a bit (first Z had points) I wouldn't run a point distributor unless it was absolutely necessary.

Tried with and w/o the resistor in virtually all situations. In all cases, it worked better with the resistor bypassed, but still not as reliable as the points.

Oh, to be honest, I can't say that I won't try it yet again. After all, I already own the stuff, eventually I'll convince myself that there must be a way to get it to work.

But the most consistent problem has been spark wash-out at anywhere from 3500 RPM on up, the exact point it fails depends on what other config I have running at the time. Things like ballast or not, wide or narrow plug gap, which coil, etc.

It's worth noting that while I've seen this failure-to-rev complaint now and again with the Pertronix, I also experienced it with the ZX dizzy. This is what leads me to believe that the root cause is my car, not the ignition per se. The most likely theory in my mind at this point is my car has too much voltage drop at the ignition coil and such.

[Walter Moore]

I've been working on Z's for quite a while now and just noticed that the 240Z dizzy #1 position is 60 degrees off compared to the 280Z's...

I don't know about the 280Z, but the 280ZX distributor does have this characteristic . I pulled the oil pump and repositioned the distributor drive shaft to resolve the alignment issue.

Arne:

There is nothing intrinsically wrong with running points, so long as the distributor bearings are in good condition. As you state, cars used them for years. The only real down side is increased maintenance. If the car isn't a daily driver, and the points are working for you, why switch?

I know nothing about the Pertronix. It wasn't something that I was interested in pursuing.

The ZX distributors typically do have too much vacuum advance, at least in the later years, and since the only breaker plate that is still available from Nissan is for the 83, there is a strong risk that a rebuilt earlier distributor may have excessive vacuum advance as well. So your choices with the ZX distributor are:

1. Mechanically limit the vacuum advance to no more than 15-17 degrees

(at the crank)

2. Disable the vacuum advance altogether.

(See jmortensen's post)

Either approach will prevent the spark knock so common with the ZX "upgrade".

When using the ZX distributor you should jumper out the ballast resistor, and use the ZX ignition coil as well. I also notice that there are after market ignition modules from some of the generic parts stores for $100 - $150 each. If you are going to carry a spare, why not carry a cheap one?

But if your points distributor has good bearings, and the timing is set correctly, the relative improvement from electronic ignition will be difficult to notice.

[vercingetorix]

I would suggest disconnecting the vacuum advance and running the car at about 18 degrees BTDC timing at idle and see how that floats your boat. I got really good mileage like that with SU's. Add MSD for even better mileage and you don't have to use the E12-80 module, just run the module.

Always thought you needed the module to trigger the MSD this sounds pretty trick,how do I do it?

As for the ZX upgrade I dropped mine in and have had great starting and power across the band.

[Arne]

The only real down side is increased maintenance. If the car isn't a daily driver, and the points are working for you, why switch?

That's the point I've come back to now. In fact, I've spent far more time swapping ignition parts around over the past two years than I would have spent maintaining points. After all, I only drive it 3-4000 miles per year. How much maintenance would points take for that period? Not much.

The ZX distributors typically do have too much vacuum advance, at least in the later years, and since the only breaker plate that is still available from Nissan is for the 83, there is a strong risk that a rebuilt earlier distributor may have excessive vacuum advance as well. So your choices with the ZX distributor are:

1. Mechanically limit the vacuum advance to no more than 15-17 degrees

(at the crank)

2. Disable the vacuum advance altogether.

(See jmortensen's post)

Either approach will prevent the spark knock so common with the ZX "upgrade".

Had the detonation issue been the only problem with the ZX for my car, I'd have probably gone this route. But the detonation was only part of the issue. I still experienced the failure to rev out with the ZX ignition - indeed the revving problem was lessened if I retarded the timing so the detonation became a minor issue for me.

When using the ZX distributor you should jumper out the ballast resistor, and use the ZX ignition coil as well. I also notice that there are after market ignition modules from some of the generic parts stores for $100 - $150 each. If you are going to carry a spare, why not carry a cheap one?

Yup, that's how I ran it. Both with a used original and a brand new ZX coil. The spare module I carried in the car came from a 210 in the local pick-n-pull, paid $10 for it. It worked fine, and got my friend back home when his module failed without warning at a Datsun show. I think it is still on his car running great even now.

But if your points distributor has good bearings, and the timing is set correctly, the relative improvement from electronic ignition will be difficult to notice.

My thoughts exactly. At this point I figure I have better things to spend my time on.