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....

[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 lol.
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.

[Arne]

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.

Oh, I know myself so well. Today I put it all back.

Decided it was time for a minor tune-up today. So as part of that I decided I'd try it one more time, and give it every possible chance to work.

So I installed new plugs (NGK BP6ES), new wires (not that the old ones were bad, but I'd couldn't handle those bright blue NGK wires under the hood of my red car any more), cleaned, tested and lubed the advance mechanism, installed the Ignitor and matching 3.0 Ω coil, bypassed the resistor, and built a new, heavy-gauge power wire to the Ignitor. Set the timing to 8° BTDC, vacuum advance still hooked up.

So far, so good. Seems to pull smoothly to 6000+ in first and second, didn't drive it anywhere I could try it in the higher gears. So I'll give it another try for a while. Updates will be posted when/if things change.

[turbo 260]

Arne,
Glad to hear it's running. I had a friend who had someone else put in his electronic ignition, actually it was a Z shop, and they never bypassed his resistor. He drove from Tampa to dallas and back. He stopped by my place to see if I could figure it out. Once we bypassed the resistor the car ran noticably better. I set my car to 10 degrees BTDC with the vacuum advance disconectted ( I am running fuel injection though). May I also suggest NGK 5632 which is BCPR6E-11. The "C" means it's the smaller socket size. Drppoing the "S" changes from a standar tip to a V groove and the "-11" increases the gap to 1.1. These are a standard honda plug, so everyone usually has them in stock.
Jim

[GreenZZZ]

I dropped the Mallory Optical Distributer/Coil/Ballast in, added some beefy ground wires, set the timing and it was plug-n-play...

http://www.classiczcars.com/photopos...4&ppuser=14083

[Babalouie]

I had problems with my ignition too, and the more I "improved" it with upgraded parts the worse it got. In the end it turned out a few of the connections on the keybarrel were dodgy. Just to be sure, now I run a relay with the coil +ve getting a direct feed of juice from the battery.

Do Zs run a relay?

[barth4567]

Oh, I know myself so well. Today I put it all back.

Decided it was time for a minor tune-up today. So as part of that I decided I'd try it one more time, and give it every possible chance to work.

So I installed new plugs (NGK BP6ES), new wires (not that the old ones were bad, but I'd couldn't handle those bright blue NGK wires under the hood of my red car any more), cleaned, tested and lubed the advance mechanism, installed the Ignitor and matching 3.0 Ω coil, bypassed the resistor, and built a new, heavy-gauge power wire to the Ignitor. Set the timing to 8° BTDC, vacuum advance still hooked up.

So far, so good. Seems to pull smoothly to 6000+ in first and second, didn't drive it anywhere I could try it in the higher gears. So I'll give it another try for a while. Updates will be posted when/if things change.

Arne: I put my Pertronix in over three years ago and it still works just fine. Running the same Ngk plugs you are,Beck Arnley Cap,Rotor,and Beck Arnley 7mm wires. Left the stock coil in as well as the Ballast Resistor and really changed nothing out. Timing is about the same as yours. My distributor is the original,far from completely tight, and probably needs to be rebuilt. Original Motor has over 250k and is using some oil. Still runs fine. I do run premium gas from Chevron. Only problem I have ever had is pinging once in awhile. And yes this was after two E-1280 failures. Anyway I try to keep things as simple as I can and it works for me. I am a shadetree mechanic at best. I know how particular you are about your car. Just cannot understand why it won't work for you. Gary and Roger helped me and I have never looked back. I am planning on putting a New/Oem/ Rebuilt distributor in this summer,and having my original rebuilt. No magic here. Alot of guys seem to run different types of ignitions and if they work for them I say very cool. If you like your points and are happy that is all that really matters is it not? Or not. Just my opinion.

[Arne]

Well, my best guess as of now is that the Pertronix will work fine in most cars, but only if everything else in the ignition is good also. The differences between what I have installed now and working fine (so far) and what was failing to rev past 4500 RPM when I last went back to points are two small things: 1.) I replaced the older BP6ES plugs with a fresh set; and 2.) I made up a new power supply wire to run to the Ignitor that was much larger gauge wire than the previous wire, hoping for less voltage drop to the Ignitor.

That's all I did differently, yet this time it's running fine. The jury is still out on this, as I don't yet trust it to stay this way.

[Bruce Palmer]

I think I've mentioned this before but a great source for electronic distributors in Portland OR is www.philbingroup.com. Rebushed, recurved for points motors, NEW advance plates, ready to plug and play. Under $200 if memory serves......

[motorman7]

Wasn't sure whether to add this here or put it under the what I did this weekend thread. Seems it would be most appropriate here.

This weekend I went to the pick your part place in Oceanside and snagged a 280ZX dizzy to replace my Petronix/standard dizzy. I too had the 4000 RPM stall and was hoping this would fix it. At 4K, it seemed like the ignition was cutting out and I could actually get a gas smell, so I was thinking it was an ignition issue.

The change out was pretty easy since I already had the Petronix. I pulled the old dizzy and mount, noted the rotor location (cylinder 2) and installed the new 280zx dizzy and mount and started the cabling with rotor location being cylinder number 2.

This worked great, started right up. Odd thing was the RPM's would go up much higher than my other dizzy. Had to break out the Unisyn and lower idle speed. The thing that is odd here is if my earlier dizzy was optimized, and I think it was, why would a new dizzy bring the RPM's higher?

Anyway, I have the dizzy dialed in and I love how it runs. No more 4K stall and maybe just me, but car seems much smoother. I will keep the old dizzy just in case, but for now, it seems like a nice change. So for my Yellow '71 240 Z, I am now running a 280 alternator and 280 dizzy on a 260 motor. Talk about a hybrid.

[alhbln]

This worked great, started right up. Odd thing was the RPM's would go up much higher than my other dizzy. Had to break out the Unisyn and lower idle speed. The thing that is odd here is if my earlier dizzy was optimized, and I think it was, why would a new dizzy bring the RPM's higher?

A higher advance at idle will lead to a higher idle RPM.

[jmortensen]

This worked great, started right up. Odd thing was the RPM's would go up much higher than my other dizzy. Had to break out the Unisyn and lower idle speed. The thing that is odd here is if my earlier dizzy was optimized, and I think it was, why would a new dizzy bring the RPM's higher?

I agree with the above. Double check the timing at idle. If you are going to run without vacuum advance (which I suggest) then start with the timing at about 18 degrees BTDC and adjust a little back or forward from there as necessary. If you are going to run the vacuum advance I would guess that you will probably have too much total advance. Depending on which ZX distributor you have you will get 17 to 18 degrees of mechanical advance out of it by about 2500 rpm, plus whatever you get via the vacuum advance. Those vacuum units are almost always broken too.

[Arne]

Me three. I ditched my ZX dizzy because I didn't like the advance curve. Knowing what I know now, I'd have just ditched the vacuum advance instead.

[motorman7]

I will give that a try. Right now I have the vacuum hooked up. It will be interesting to see how it does with the vacuum removed. Will try and set that up tonight when i get home. Thanks for the input.
Rich

[motorman7]

OK, I am now running the 280ZX dizzy without the vacuum input. This is a good set-up. I get less or no ping under load than when I had the vacuum hooked up. Also, motor freely revs to 7K, which is great. No more 4K flat line. Afraid to take it over 7K as I think the tach has a slight lag and could be at 8K during a rev.

So I am doing about 75 MPH at 3K RPM. Theoretically I could do over 150 MPH in this thing before redline now. May have to try that someday to see what it could really do.

[alhbln]

How is your idle RPM now after disconnecting vacuum?

[motorman7]

How is your idle RPM now after disconnecting vacuum?

No change.

I pulled off the hose, plugged it with a 1/4" bolt and that was it. No other changes.

[alhbln]

Do you have a timing light to check whats the current idle advance is? I would second Jon's recommendation to start with 18º and then continue from there.

What is your idle RPM right now? If its between 800-1000 RPM i wouldnt worry too much about it.

[Zedyone_kenobi]

I have a european dizzy on order right now and I plan to add my experiences with it when I get it installed and dialed in. The main difference as far as I have been told is that the euro dizzy can run far more static advance as its centrifugal advance is much less than my stock 71 dizzies. I think it still has about 11 degrees of vacuum advance built in.

We will see,

my thanks to Walter Moore for the education on the types of dizzies I can run.

FYI, currently I have a stock 240Z dizzy with a pertronix unit with a flamethrower 3 ohm coil, resistor bypassed and running 5° BTDC. Basically just like Arne.

[motorman7]

Do you have a timing light to check whats the current idle advance is? I would second Jon's recommendation to start with 18º and then continue from there.

What is your idle RPM right now? If its between 800-1000 RPM i wouldnt worry too much about it.

Actually, I don't have a timing light. I have always done it by feel. I usually advance as much as I can until I get engine ping under load. Then I back off just a bit, so just a trace of ping under load. I plan on buying one some day soon here.

The idle is about 800-900.

Funny, last time I called Pep Boys for a timing light the youngster on the other end thought it was a device to turn your house lights off and on. We are dating ourselves here.

[Z train]

Actually, I don't have a timing light. I have always done it by feel. I usually advance as much as I can until I get engine ping under load. Then I back off just a bit, so just a trace of ping under load. I plan on buying one some day soon here.

The idle is about 800-900.

Funny, last time I called Pep Boys for a timing light the youngster on the other end thought it was a device to turn your house lights off and on. We are dating ourselves here.

Go hit some pawn shops.There are screamin' deals to be had these days.

[jmortensen]

If you want cheap, Harbor Freight sells a regular timing light and one with advance:
http://www.harborfreight.com/xenon-t...ight-3343.html
http://www.harborfreight.com/timing-...nce-40963.html

[motorman7]

Will see about picking one up before the Laker game tomorrow. There is a harbor freight about a mile from me. Will pick up on way home. Thanks for the tip.

Rich

[Zedyone_kenobi]

Just to keep this thread full of useful insight. I took out my gal for a spin last night, after being parked for well over a month. She had a horrible time getting past 5000 rpm. Two months before at a track day she screamed to 6500 with NO hesitation.

Certain things come to mind, as I did not change anything:

1) Ethanol, ethanol. I wonder if the gas is going south after sitting for well over a month.

2) I had a very low battery after sitting for so long, car barely started, and I noticed that my amp gage was reading very positive which to me means the alternator trying to charge the nearly dead battery back up. That low voltage may have been hurting my pertronix output

What I am going to do to try to solve this.

First the easy stuff. Check timing (that solved all my revving problems before)
Second, tune up, new plugs, cap/rotor, fuel filter
Third 60 amp alternator upgrade from MSA
Fourth, Fill up with fresh ethanol free gas

I will let you know of the results

if I keep putting these small projects in front of my tranny swap I will never get it done. But that is how these things happen

[Arne]

Can I recommend/ask that you do these steps one at a time to see which one clears the problem?

Last time I had this issue, I replaced the plugs with a fresh set of NGKs and that took care of it.

[Zedyone_kenobi]

Actually Arne, with my energetic 2 year old running the roost lately, I will HAVE to do them one at a time! HA HA

[Arne]

Don't know which is worse to have in the house - energetic 2 year olds, or hermit 25 year olds...

[Zedyone_kenobi]

If I ever make it back up to Oregon, I will have to come by and we can compare war stories. I bet you will win though.

[ktm]

2) I had a very low battery after sitting for so long, car barely started, and I noticed that my amp gage was reading very positive which to me means the alternator trying to charge the nearly dead battery back up.

That is one way to shorten the life of an alternator. Try to keep the battery charged using a battery tender, otherwise you'll be out a battery and an alternator at some time.

[Zedyone_kenobi]

Noted. I think I will pick up a battery tender.

[duffman]

Harbor Freight, $3.99

[mlc240z]

Don't know which is worse to have in the house - energetic 2 year olds, or hermit 25 year olds...

2year olds.
25 year olds you can just open the door and throw in some raw meat.
They'll survive.

Energetic 2year olds you have to catch and then try to feed.

[Arne]

That was a long time ago - I've forgotten what that is like to have 2 year olds in the house.

[d240zx2]

2 year-olds are a ton o' fun. Spoil 'em like crazy, then send 'em home.

[d240zx2]

Zedy, if you know where to get ethanol-free gas, let me know, will ya?

[Zedyone_kenobi]

Nothing anywhere I have found near us Frank. Need to keep as little of that crap in the tank as possible. I think if I can fill up more often, I can at least keep fresh gas in the tank.

[Zedyone_kenobi]

UPDATE:

Yesterday I had some time to fiddle with the Z. First I checked my timing. Still about 5-7 degrees at 800 rpm static, so I am happy about that. I think it should be more stable, but it will do for now. First thing I did was change the plugs/cap/rotor. (plugs looked a beautiful light brown, she is burning cleeeaaaannn) 15 minutes later, I was out the garage and yup, still had my popping and spitting at 5000 rpm. Pulled back in. Next I changed my fuel filter. Out the garage I went for the second round, and the car immediately shot to 6500 rpm when I floored it in 1st and 2nd gear with no drama at all. I was starting to smile. Did some driving and again, no issues pulling very hard all the way to yellow line.

I was very pleased. I still need to hook up my 60amp alternator and plug in module (nice instructions Arne), but I was happy. One thing I did find out is when I rev the car very slowly in gear, meaning I do not floor it, just part throttle and I creep up on 5000, it will still pop once or twice until I put the pedal down to the floor. Perhaps I am still running a bit rich. Judging by the plugs I would say that is not really the case.

Anyway I went from hitting a wall sputtering and spitting at 5000 rpm to smooth pull to redline with a fuel filter change and tune up. I have to physically try to make it pop now and it is not easy. I am going to try to check my wiring to my coil like Arne did, maybe run a larger wire, and install my 60 amp alternator next. If I can still find a way to make the engine hesitate, I will resync my carbs. I have not touched the air/fuel on the bottom of the carbs since I got them installed from Ztherapy. I turned each of them half a turn and ended up putting them back to where they were. And they were balanced spot on in 10 minutes. LOVE my carbs.

Although, I did balance them with the air cleaners base plate with the horns not on it, and I think I need to balance it again with that part on the car. I figure you should balance the carbs in as close to running condition as possible.

[mlc240z]

Had hit the 4500rpm wall also.
Already have the alternator upgrade in place.
Still have to recheck the timing, pulled the plugs and even tho I felt it was running a little rich, light brown....all 6 look good.

Only thing I did different was in the past few trips to get gas, have been putting in the mid-grade 89 octane, not regular 87. Yesterday splurged and put in 6 gals of 91 (all Sunoco).
Coming home from a drive (not sure if it had enough time to reach the 89-91 mix), punched it thru and now up to 6 grand before it started to stumble/plateau.
I'd guess the octane made a difference, but a little clatter prior to the 91 makes me think I need to recheck the timing.
I'll try re-balancing with the back plate on. Don't know if it'll make any difference, but what the hell.

[Zedyone_kenobi]

Installed my 60 amp alternator today with custom plug. Could not be easier. Great instructions Arne!

Took the car out for a drive. MY old alternator was only putting out 12.4 volts, my new one gets 14.5 volts. Very strong. I am getting almost 13.89 volts to the hot side of the coil, versus 12.2 volts. Car runs liquid smooth now. I cannot make the car hiccup or bog, or pop or sputter. Ran strong all the way to 6500 and even was smooth under all combinations up to that magical 5000 rpm band. I am very pleased. I swear the extra juice makes the fan blow stronger, but it is probably my imagination. I do wonder if it will effect my headlights since my old alternator was so marginally charging.

[motorman7]

I swear the extra juice makes the fan blow stronger, but it is probably my imagination.

Increased voltage in DC motors makes them run faster. Increased amps improves available torque (assuming it's needed). It's not your imagination...assuming you are running an electric fan.

[Zedyone_kenobi]

I get the engineering behind it and all (BS in MCHE), I was alluding to the fact that I am not sure I can actually feel 1 extra volt.

[GreenZZZ]

It felt like I got 5-10% more horsepower after the alternator upgrade even though I didn't hit an RPM wall prior to the upgrade. I run 92-93 octane with an E31 head.

[Arne]

So today, not quite five months after I put it all back in, I took it back out again.

To recap - back in April (at 70,500 miles) I re-installed the Pertronix Ignitor and 3Ω coil, along with a good old-fashioned tune up. New plugs, wires, valve adjustment, cleaned and lubed the advance mechanism, and new wiring to the Pertronix. This seemed to work. For a while.

But as the Summer has gone by, I've noticed an increasing tendency for the ignition to washout. At first it was just a bit if I ran it up over 6000. So slight, and I run it that high so seldom, that I wasn't sure it was happening. Then I started noticing it over 5500. Recently, it became noticeable just over 5000 RPM.

So I went back to the used points and original 39 year-old coil. No other changes at all. Runs perfectly all the way to redline again.

So during the driving I have done this Summer, something has changed/worn just enough to cause a return of the problem. It's worth noting that I have driven it a total of 1000 miles since putting the Pertronix back in. That's not much wear. Perhaps I could fix it with another fresh set of plugs. But plugs every 1000 miles? I'd rather change points once every year or two.

I had hopes that doing it all correctly back in April would have been enough, and the initial results were encouraging. But in the end, it certainly appears that for whatever reason, my car is simply not a viable candidate for electronic ignition.

[alhbln]

This might be a problem with the Ignitor overheating, i had similar effects with an Ignitor installation where the engine would start to run rough above 5000 RPM, then gradually it got worse until i let the engine cool down, and everything would be fine until the engine heated up again. Did you notice the same issues with a cold engine?

The overheating issue seems to be a design fault with the Ignitor. The Pertronix Ignitor uses an IGBT transistor for driving the coil, which lowers the coil current for circuit protection when the temperature rises considerably.
Up to 150ºC internal temperature everything works nice, then the current drops progressively up to 175ºC where the available current is below 1A.
The round mounting plate of the Ignitor is the heat sink of the IGBT, but as the engine (and thus the mounting plate) easily heats up to 80-90ºC, the IGBT can't cool down and warms up even further, up to a point where the coil current is so low the ignition starts to cut out.

You could either use a points or Pertronix Ignitor setup to drive an external (robust) transistor ignition, as example a MSD 5900 or convert to an optical pickup and transistor ignition such as the Crane XR700.

Good luck,
Adrian

[Arne]

This might be a problem with the Ignitor overheating, i had similar effects with an Ignitor installation where the engine would start to run rough above 5000 RPM, then gradually it got worse until i let the engine cool down, and everything would be fine until the engine heated up again. Did you notice the same issues with a cold engine?

Not temperature related, same thing hot or cold. I still tend to think it has to do with voltage. If I make a change that reduces the resistance to spark (i.e. new plugs), or to decrease the resistance/voltage drop to the coil it gets better. I'm currently highly suspect of the wire to goes to (and then returns from) the early four-wire tach.

[alhbln]

Sounds like the supply power wiring if its not temperature related, but then the symptoms would be the same when changing to a points ignition setup, as the supply wiring itself does not change.

The symptoms you mentioned could indicate a defect Pertronix coil. If there is a broken wire or short in the secondary (output) winding of the coil, the output voltage would be quite low and barely sufficient to create a spark, especially at higher RPM. You could run the factory coil and resistor with the Pertronix ignitor as a test, the combination is equal to a 3.2 Ohm coil.

[Arne]

Sounds like the supply power wiring if its not temperature related, but then the symptoms would be the same when changing to a points ignition setup, as the supply wiring itself does not change.

The symptoms you mentioned could indicate a defect Pertronix coil. If there is a broken wire or short in the secondary (output) winding of the coil, the output voltage would be quite low and barely sufficient to create a spark, especially at higher RPM. You could run the factory coil and resistor with the Pertronix ignitor as a test, the combination is equal to a 3.2 Ohm coil.

I've tried that. My notes tell me that it was much the same with the OE coil and ballast, better (i.e. higher RPM before it stops revving) with the stock coil and the resistor bypassed.

[alhbln]

That leaves the Ignitor, which seems to have gone bad, or the magnetic shim had a bit of play and started to vibrate at high speeds but i guessed you checked that already.

I don't think its a problem with the supply wiring as your points setup is ok and the Ignitor is merely an electronic version of the mechanical switch, so your wiring seems to be fine.

[soundmasterg]

In 2 years I've had three Pertronix units....one was my fault but the other two developed the same problem you mentioned Arne. I swapped them under warranty and the one I am using now is perfect and has been in there for over a year. The first one would get hot and the car would flat out quit, usually when idling. The second one got too hot also and would miss at high rpms. I found out that I needed a new gasket between the distributor and it's mounting point on the block. Just replacing that gasket reduced the heat just enough to where the new one has behaved fine. The third one that was my fault failed because I had it disconnected, and reconnected the wires backwards by accident. Woops.

Overall I am happy with the Pertronix as my distributor was a bit worn and didn't work well with points at all....cutting out about 5000 rpm. The Pertronix works fine up to the redline and the car is faster too. Eventually I am doing a turbo swap and will use coil packs and get rid of the distributor.

Good luck with yours!

Greg

[alhbln]

Eventually I am doing a turbo swap and will use coil packs and get rid of the distributor.

Speaking of coil packs :-) Looks not really out of place as the spark wires are coming from the same location.

[Arne]

Well, I can't seem to leave this alone.

I did some testing a few weeks ago that indicated the Pertronix Flamethrower 3.0Ω coil was not up to spec. I put it in the car for testing and it actually failed. No start, no run.

OK, a totally failed coil I can understand. As a replacement I bought a Crane PS20, which is rated at 1.4Ω and includes a matching resistor in the box. Thought maybe I could get it to work this way. (When will I learn?)

Still failed. In fact, the combination of Pertronix Ignitor with the Crane coil & resistor may have been the complete low point of all my testing through the past 3-4 years. It was hard pressed to rev much beyond 3000 RPM that way. Bypassing the resistor made it drivable, but still washed out at 4200 or so. Total waste of time.

And here's the part that always gets me - while my car runs fine on points with the stock (40 year-old) coil and resistor, it does NOT run fine with those same points firing one of the other coils. I could get it to run pretty well on points with the Crane coil if I bypassed the resistor, but with the resistor in place (as it really should be used with points) I got much the same result as with the Pertronix Ignitor in place.

In other words, my car only runs right with all its factory ignition parts. Change any one of them for something "better" and the car won't rev out. This is troubling to me - someday that 40-year old coil will die, and nothing I've tried to use in its place so far has worked.

So far I have tried:

Distributors:

• Factory 1971 240Z distributor (D612-52) with stock points
• Factory 1971 240Z distributor (D612-52) with Pertronix Ignitor
• Factory 280ZX w/E12-80 (two different examples, each tried with more than one module)

Coils:

• Factory 1971 240Z coil (1.6Ω)
• Factory 1982 280ZX coil (used)
• Aftermarket stock replacement 280ZX coil (new)
• Pertronix Flamethrower coil (3.0Ω)
• Crane PS20 coil (1.4Ω + included resistor)

The only config that works flawlessly is all stock with points. The Ignitor/stock coil/bypassed resistor is close, but I dislike not running the resistor because I fear the increased voltage through the inductive loop on the tach could possibly hurt the tach over the long haul, plus I don't know how that coil might hold up at full voltage all the time either.

It would be interesting to try a ZX dizzy again, as I've learned a bit more about my car's behavior now. But I sold that stuff long ago, and I am really getting a bit tired of spending money chasing the ideal ignition, when what I already have now is good enough.

[soundmasterg]

If you're interested in a backup Arne I have a NOS in the box coil for a 240Z. Let me know via PM (or I may forget to check here) and I can bring it to the show tomorrow if you want to look at it.

Greg

[alhbln]

The Bosch red coil/ballast resistor (0 221 119 030) works well as a replacement for the factory coil, it has the same primary resistance and will even give a bit more output.

[FastWoman]

Arne, I really don't run my engine up in the 6k range, so perhaps I haven't really challenged my ignition a lot, but I've been very happy with my stock '78 distributor, an MSD Blaster II ignition coil (no resistor), and a GM HEI ignition module with a big heat sink on it. It's not very sexy, but it's worked great for a year now. The HEI module was CHEAP -- $11, as I recall. There are more expensive ones for higher performance, as I understand.

[Arne]

Thanks for all the suggestions, everyone. I still don't know where I'm going to go on this. I don't really NEED to convert - the points and stock coil work fine for my purposes. But it nibbles at me, and eventually I have to take another try to make it work.

Obviously, there are far more options available than I have used thus far. But I am - as always - hampered a bit by my desire to maintain either stock or period-correct appearance, even under the hood. That desire eliminates a whole lot of choices...

[Arne]

Tried something new today - re-installed the Crane coil only, left the points and factory resistor in place. But I bypassed the tach. Went from the "resisted" end of the ballast straight to the positive terminal on the coil. Took the tach and that long run of wire out of the loop. Result? Same as before, started cutting out at high RPM. Re-installed stock coil, all is again well. So that looks to eliminate the tach circuit as a cause.

I think I'm fighting two different issues on this. One of them still seems to be insufficient voltage to recharge a higher output coil quick enough at high RPM. This is what gives the problem with aftermarket coils when used with my points.

But I also have issues with the Pertronix when used with the stock coil. And there I believe that the dwell time on the Pertronix is too short - again leaving the coil insufficient time to recharge before the next spark is required.

Which is why combining the two (Pertronix and hi-output coil) typically works so badly.

Will probably do some voltage checks at the coil with the engine running later today.

[Arne]

Well, there goes one more theory.

Checked voltages.

Ignition on, engine off:

• At battery - 12.8v
• At hot side of resistor - 11.2v
• At resisted side - 5.9v

Aha! Looking like I may have an issue.

Until I checked with the engine running:

• At battery - 14.5v
• At hot side of resistor - 14.0v
• At resisted side - 11.2v

Back to the drawing board...

[steve91tt]

Did you try the voltage measurement as a function of RPM? Maybe my logic is incorrect but I'm thinking more RPM means more current and therefore the potential for voltage drop as the components could become resistive with higher current draw. You might also jump straight from the battery to the resistor with a fresh wire, temporarily, for testing purposes.

[240dkw]

Arne: Have you tried replacing one or both of the capacitors.Your High-output coil problem could be caused by a faulty capacitor, I copied this from another web site." When the points open the capacitor is connected in series with the coil. The voltage/current generated by the collapsing magnetic field charges the capacitor. This is the voltage/current source that is induced into the stepped up secondary winding. A coil opposes current flow while a capacitor enhances current flow. The enhancement of the capacitor balances out or cancels the opposition of the coil. The result is a faster collapse of the magnetic field and the highest possible voltage generated in the primary circuit. It's true that the capacitor reduces or prevents arcing at the points but its main function is to provide a circuit path for the coil after the points open and to speed up the collapse of the magnetic field."
Dan

[Arne]

Hmmm. That's a thought. I normally have not been hooking up the condenser on the dizzy when I try the Pertronix in it, but I have been connecting the condenser on the coil, in all cases. I seldom use the radio, perhaps I should try the Crane coil without?

[Arne]

Well, apparently the condenser/capacitor/whatever that connects to the negative terminal of the coil is a required part. The car will barely run w/o it. And since it is original, I'd like to replace it. It does not show separately in the factory parts book, appears to come only as part of the "Ignition coil assy." Any ideas on where to source the correct part?

[Walter Moore]

Interesting... you have a capacitor between the negative side of the coil and the frame? Is that shown in the FSM? I never had a capacitor there, even when I was running points. Now that I have the S130 distributor (and a stock S130 coil) I have no capacitors in the ignition system at all. (Except as they may exist inside the E12-80, but those can't be very large if they exist at all)

[Arne]

Interesting... you have a capacitor between the negative side of the coil and the frame? Is that shown in the FSM?

I find no mention of it in the FSM, but it does appear to be in the parts drawing, but has no separate number listed.

I tried disconnecting it, but the car was obviously not at all happy without it, missing and coughing badly even at idle.

[240dkw]

Arne: That's Odd, mine is on the positive side. The sticker on it reads "ncc nc-47ct-a2 150v.47m" I bought this car in a non-running state so I can not tell you if mine is correct.
Walter: There are a total of three on my car, + coil, points & voltage regulator.
Dan

[Arne]

My car has the same three, but the one at the coil has always been on the negative side to the best of my knowledge. It has the exact same label as yours, Dan. As I said, it doesn't like to run w/o it.

[Zed Head]

I have seen where people have attached the HEI module to the bottom of the distributor. Maybe this is an option for retaining the stock appearance, but getting the advantages of electronic ignition. It would require a ZX distributor with a VR, but might be worth the effort. The more I read of the HEI module's design and function, the more impressed I am. They really packed a lot of function and durability in to a small, simple package.

[240dkw]

Arne: I did some quick reading as to what the Capacitor/condenser (same thing) is for on the coil and it looks like it is used to boost the voltage of the primary windings. I wonder if the newer hi-output coil would work without it?

[Arne]

I wonder if the newer hi-output coil would work without it?

The Crane PS20 does not.

Did your reading confirm whether the negative or positive side?

[Zed Head]

I mis-wrote in my previous post. A 280Z distributor would give the VR, that would work with the GM HEI module, and more stock appearance without the big box of the ZX on the side.

My 280Z has an inline capacitor that runs back to ground at the distributor. I don't know where the other end goes. Otherwise the coil does not have one attached to either post, and nothing is shown in the wiring diagram for the ignition circuit. I think that for EMF noise reduction the capacitor just needs to be attached to the line that's being protected from the noise. But I don't think that the electronic ignition coil uses one because the "dwell" and coil charging is controlled by the ignition module.

And I just took a quick look at the ignition circuit in the Engine Electrical section for 1972 (because I need to know now) and it shows the condenser connected to coil (-) along with the points.

[Arne]

1.) I don't think trying yet a third type of EI is worth pursuing at this point. Both the Pertronix and ZX ignitions are well-known quantities and work fine on many (most?) 240Zs. Trying something else without discovering the root issue seems like a waste of time and money to me.

2.) My '71 FSM shows a single condenser connected to the points as well. But I can find no documentation on the OTHER condenser mounted with the coil. Since the car does not even want to run at all without the one at the coil, and both condensers appear to be original to the car (and therefore ~40 years old), I think it'd be prudent to replace them. If I could only find the one by the coil listed somewhere....

I still have to assume that I'm missing something here, something quite basic. So I'm going to leave the Crane coil in place for now and replace all the rest of the points ignition parts. I need to start fresh.

[240dkw]

Well, apparently the condenser/capacitor/whatever that connects to the negative terminal of the coil is a required part. The car will barely run w/o it. And since it is original, I'd like to replace it. It does not show separately in the factory parts book, appears to come only as part of the "Ignition coil assy." Any ideas on where to source the correct part?

Arne: I measured a couple of capacitors that I have and they are a .47 uF , so the part number ncc nc-47ct-a2 150v.47m equates to a 150V dc, .47 uF capacitor. (.47M, .47 uF, .47 micro Farad are all the same thing) If you want see if it is the cause of any of your problems you can this size of capacitor at any electronics store. It would not look correct, but will work for troubleshooting. As well, I was wrong about what the cap is used for. as near as I can tell, it is there for the reason you first eluded to, noise suppression for the radio. Which does not explain why it will not run without it? I dug through my part boxes and found 6 coils and 4 have it on the + terminal and 2 have it on the - terminal. Dan

[Arne]

Time for systematic testing.

Baseline config:

• Points (~12k miles)
• Condenser at dizzy (unknown age)
• Cap and rotor (~12k miles)
• Wires (~1k miles)
• NGK BP6ES-8 plugs, ~3k miles, great shape, 0.8mm gap (.032")
• Original coil
• Original resistor connected
• Original condensor at coil connected to negative terminal on coil
• Timing 5° BTDC (factory spec)
• Dwell angle 38° (factory spec 36-41°)

Results and notes:

• In this config, the car runs fine throughout the rev range.

[Arne]

Test #1

Changes from Baseline:

• Replaced original coil with Crane PS20 (1.4Ω)

Results and notes:

• With no changes other than the (presumably higher output) coil, the car runs as before until over 5000 RPM, where the spark appears to begin to break up and miss.
• Car will not run well at all if the condenser at the coil is disconnected. Hard to start, very bad idle, won't rev. Since I believe this condenser was intended only for radio noise suppression, this seems wrong to me.

[Arne]

Test #2

Changes from Baseline:

• Crane PS20 (1.4Ω) from Test #1
• Installed fresh points and condenser at dizzy
• Dwell angle 40°
• Disconnected condenser at coil

Results and notes:

• Car runs fine throughout the rev range again.
• Car would not even start with the coil condenser connected to negative terminal, but started immediately when I disconnected it. I wonder if the correct connection to suppress interference may be to the positive terminal of the coil. Connecting it to the negative terminal may have been a stopgap to compensate for a bad condenser at the dizzy?

Hmmm. I wonder if that condenser at the coil may have been the root cause of all my issues. I'm not going to jump the gun, will continue to step through this sytematically.

[Arne]

Test #3

Changes from Baseline:

• All changes from Test #2
• Replaced original resistor with the new one that shipped with the Crane PS20 coil

Results and notes:

• Car runs cleanly throughout rev range again. No change from the results of Test #2.

[Zed Head]

Have you checked the condenser/capacitor for proper function? Maybe it is wearing out, has turned in to a resistor and is hindering your coil charging. As I understand things they usually die completely but if the dielectric material started to break down it might leak current slowly. Many multimeters have a capacitance measurement function, but at the least the condenser should show infinite resistance.

FWIW, I have a condenser on my negative post but only for noise reduction to the tachomoter. I installed a Z31 coil and my tachometer stopped reading correctly, until I added the capacitor. I put it on the negative side because that's the side the tachometer sees. But that's another story, my point is that I have a condenser on my coil (-) post and everything works fine. This is a 280Z with the stock ECU , GM HEI module and a Z31 coil.

[Arne]

Test #4

Changes from Baseline:

• All changes from Test #3
• Re-installed Pertronix Ignitor.
• Timing set to 5° BTDC as before.
• Pertronix dwell angle checked at 35°, non-adjustable.

Results and notes:

• Car runs cleanly throughout rev range again. No change from the results of Tests #2 & 3.

Note that the only difference between this latest test and the test run w/Pertronix immediately after the arrival of the Crane coil (where the car ran bad enough that I actually pulled over and bypassed the resistor just to get home) is that the condenser at the coil is disconnected. I hear no radio interference, the motor runs great, and all seems good.

Now we'll have to see if it holds up this time. But I'm optimistic about this for the first time in a long while.

[240dkw]

Arne: this does look promising, are you going to try the positive side of the coil or leave it alone if it works well.
Dan

[Arne]

For now, I've completely removed it. I'll do some research eventually to figure out where it should/would have been connected from the factory. Still want to try one more test - wide-gap plugs. Will do that in a few days.

[sparrow6190]

any update? every time I ever had an ignition problem it was a "doh!" moment lol, its actually quite simple on every year except they made every year a little different...! ugh lol

oh, and as for running a zx dizzy and having problems like you said earlier (the autos have a 9* t-bar, and i think lighter springs, manuals have the 8.5 and a bit stiffer springs i think, but ive seen all different kinds...), the closest zx dizzy to an actual 240Z dizzy you could get would be an automatic with no vacuum advance hooked up, but you still would have very minimal mech advance so it would not be any sort of upgrade from the original points lol, not if they are working fine.

[Arne]

No change since test #4. Still working fine. I now suspect that the pair of condensers (one bad, and one possibly mis-connected to compensate for the bad one) was the cause all along. I still want to try a set of wide gap plugs (preferably BP6ES-11, as other than the gap those are identical to what is working now), but I haven't gotten around to picking a set up yet.

[240zdave]

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.

Jon, when you say bridge the ballast resistor, do you mean get rid of it entirely? I race a 240Z in ITS, and I'm running a Pertronix, MSD 6AL, an MSD Blaster coil, and the distributor vacuum advance is disabled, with no ballast resistor at all. I took my 240Z street car down to John Williams in Atlanta to get the same setup, and we had a hard time getting the thing to run. The final setup includes the ballast resistor, but basically using it (I think) as terminal posts for termination/connection of some of the wires. I wanted to try taking out the ballast resistor to match the setup in the race car, but it was getting dark, and I had to get back to Nashville, so I have not tried that yet. The car runs great, but I don't know if I giving up some performance with the ballast resistor still there.

[SteveJ]

If you want to run without a ballast resistor, you need to get a 3 ohm coil. The resistance has to come in somewhere.

[Arne]

Test #5 (Final)

Changes from Baseline:

• All changes from Test #4
• Installed new NGK BP6ES-11 spark plugs, pre-gapped at .044" (1.1mm)

Results and notes:

• Car still runs cleanly throughout rev range. Can come off choke much sooner.

This was the last piece to implement. The wider-gap plugs give better spark, which is definitely noticeable in the need for less choke when cold.

It seems quite apparent now that my issues from the beginning were related to the condensers. The condenser at the coil is still not connected.

[jmortensen]

Jon, when you say bridge the ballast resistor, do you mean get rid of it entirely? I race a 240Z in ITS, and I'm running a Pertronix, MSD 6AL, an MSD Blaster coil, and the distributor vacuum advance is disabled, with no ballast resistor at all. I took my 240Z street car down to John Williams in Atlanta to get the same setup, and we had a hard time getting the thing to run. The final setup includes the ballast resistor, but basically using it (I think) as terminal posts for termination/connection of some of the wires. I wanted to try taking out the ballast resistor to match the setup in the race car, but it was getting dark, and I had to get back to Nashville, so I have not tried that yet. The car runs great, but I don't know if I giving up some performance with the ballast resistor still there.

Sorry, missed this. You will increase the voltage to the coil without the ballast. The resistor is there to lower voltage so that the points last longer. You don't have to remove it, just run a jumper wire from one side to the other.

[dhoneycutt]

When I installed the Crane ignition (XR3000 with PS91 Coil) in my 72, I was instructed to jumper the ballast resistor. I have not had any issues since I installed it a few years ago. I hope you get it all figured out Arne.

[mlc240z]

Good to hear, Arne.

How is your tach? Does it still show rpm's thru to 6-7K? Does it bounce around after 4K?
Are you running the original '71 tach?

[Arne]

When I installed the Crane ignition (XR3000 with PS91 Coil) in my 72, I was instructed to jumper the ballast resistor. I have not had any issues since I installed it a few years ago.

Whether or not you should jump the resistor varies depending on the coil, mostly. In my case, the Crane PS20 coil not only said a resistor is required, but it actually came with its own matching resistor in the box.

How is your tach? Does it still show rpm's thru to 6-7K? Does it bounce around after 4K?

Throughout the entire process, my tach has worked perfectly. No issues in any config. Specifically, no bouncing, and runs with the revs all the way to redline.

[240zdave]

Sorry, missed this. You will increase the voltage to the coil without the ballast. The resistor is there to lower voltage so that the points last longer. You don't have to remove it, just run a jumper wire from one side to the other.

If you're talking about the points in the distributor, I'm running with a Pertronix, so no points. Race car setup is MSD6AL, MSD Blaster II coil, NGK Iridium plugs gapped to 0.050, a Pertronix, and vacuum advance disabled on the distributor. Street car is similar, with MSD6A, MSD Blaster II coil, NGK Iridium plugs gapped to 0.050, a Pertronix and vacuum advance disabled on the distributor. No ballast resistor at all on the race car, but still have it on the street car. I'm at work right now, and so can't tell you which wires are connected to the ballast resistor on the street car. My point is, if it works on the race car, it should work on the street car. The street car seems to be running fine, although I rarely rev the engine beyond 4500 RPMs.

[jmortensen]

I was pointing out why the ballast resistor was there in the first place. If the points are gone and you're running the Blaster II, jumper wire across the ballast will give a hotter spark.