Crane Cam XR7000

[MAX]

I'm a novice regarding ignition systems and am thinking of replacing the standard points ignition on my 73 240Z with an electronic ignition system.

What advantages does this provide?

And I have been considering using the Crane Cam XR 7000.

Aside from the fact that the Crane Cam unit allows you to replace the points with a non contact electronic method to control the coil what other functions does it provide? ie what else does it do? Does it change the spark characteristics for starting vs running, etc.

Lastly, In reading through some of the archives I've come across some a couple achronyms like "dizzy" and "MSD". What do these mean?

Many thanks

MAX

[montoya_fan01]

I'm a novice regarding ignition systems and am thinking of replacing the standard points ignition on my 73 240Z with an electronic ignition system.

What advantages does this provide?

And I have been considering using the Crane Cam XR 7000.

Aside from the fact that the Crane Cam unit allows you to replace the points with a non contact electronic method to control the coil what other functions does it provide? ie what else does it do? Does it change the spark characteristics for starting vs running, etc.

Lastly, In reading through some of the archives I've come across some a couple achronyms like "dizzy" and "MSD". What do these mean?

Many thanks

MAX

dizzy = distributor

msd == an aftermarket brand of ignition systems (Multiple Spark Discharge, i believe)

i put a pertronix ignitor system in my car to replace a Crane XR700 which was causing me no end of problems. it was cheaper and in my car it performs 100% better. No points to bounce at high RPM, engine pulls harder and revs higher than it did with either the points or the Crane system, AND it was less expensive & easier to install.

as for the benefits of Crane or Pertronix, and/or MSD system, I'd suggest checking out the websites for Crane and Pertronix for a comprehesive list of the claims made by the manufacturers and compare that to the opinions you get here and elsewhere.

[chema32]

i havent used the xr-700. but i do have the xr-3000 and it performs excelent my car started allot easier and ran allot better...the only bad part is that if one of the wires ever comes loose any bit it will melt due to the high voltage. it has melted my distributor cap from the connection and also a bit off the coil. but i also had 8mm wires so that was the cause. all i did was snip off the coil wire boot and plug it directly into the coil and distrubutor.(the boot was making the wire disconect)

[240ZMan]

Disclaimer: I am oversimplifying the details of how the various components of an ignition system operate. To those who already are familiar with this, please "cut me some slack" - I don't want to write a term paper

The job of the ignition system is to generate a spark at each plug at the correct time. To accomplish this, two things have to happen:

#1) The distributor has to determine when to fire the coil that generates the spark

#2) Energy must be applied to the coil at that moment.

In the early Zs, mechanical points were installed in the distributor and they opened/closed every time another spark plug needed to receive a spark. The points were moved by 6 eccentric lobes on the distributor shaft. This both controlled the timing as well as applied the energy (voltage from the electrical system) to the coil. It was simple and reasonably reliable, but it was difficult to adjust and since the points were handling a large amount of current across an inductive load (the coil), the points would wear out. This resulted in cold start difficulties as well as poor spark at high revs.

Electronic ignition systems still have to perform the 2 functions above. In the case of later 280Zs, the points were replaced with a sensor and magnets. The magnets are on the distributor shaft inside the distributor and rotate in front of the sensor. As they pass by it, the sensor generates a very small voltage. This accomplishes #1 above. The voltage is then sent to the ignition module which can be thought of as a simple amplifier or switch: it takes the small voltage from the sensor and then switches a larger voltage across the coil to make the spark. This accomplishes #2 above. The advantage is that there are no contacts (points) to wear out and the system is more stable at high revs. Note: the voltage generated by the magnets/sensor is far too weak to directly drive the coil. That's why a separate ignition module is required.

For a mostly stock Z, the stock 280Z/ZX ignition system is quite adequate assuming it is in good condition. For those with an early points Z, there are various approaches to replacing the points:

a) retrofit the later Z/ZX system (distributor and ignition module). This works well and can be done economically.

use a self-contained after-market system. Pertronix is the best known example. It is a small module that is installed in place of the points. It performs both #1 and #2 above. Because of its small size it is limited in how much current it can safely handle, so it should only be used with the stock coil, or one that is just slightly more powerful (as measured by its resistance - with coils, "lower resistance" means "more powerful").

c) use a modular after-market system such as MSD or Crane. These devices only address #2 above (applying energy to the coil) and rely on something else to provide them the signal for #1 above. The advantage of the MSD and Crane is that they are physically larger so can handle greater loads and hence more powerful coils. They also have a temporary energy storage circuit so they provide additional energy to the coil beyond what the car's electrical system can provide on its own. MSD goes further and provides several sparks in a row to each plug for each signal from #1 above. The idea is to help with combustion at low revs. By about 3k rpm there is no longer enough time to generate multiple sparks and the system reverts to a single spark per trigger from #1. In practice, I found some small benefit with triple webers (always rich), but none when I switched to fuel injection. Keep in mind that the MSD/Crane box can be triggered by the stock points, a Pertonix device, the stock electronic distributor, or after-market distributors.

A note on coils: a coil takes a low voltage (14V) source at several amps and converts it to a high voltage (10k+ volts) at several milliamps. More aggressive/powerful coils have a lower resistance on the low voltage side meaning they pull even more current than a stock coil, and are thus able to generate a more powerful spark. In practical terms, the stock points as well as Pertronix units cannot handle these low resistance coils.

The main benefit of a more powerful coil is that you can run with a larger spark plug gap and still maintain a strong spark. For a non-racing engine this is of theoretical benefit, and my own informal testing did not show any observable benefits when I increased the gap. I'm not saying that some people won't find benefits on the street, but if you're looking for areas to improve the performance of your Z, this is one with very limited return.

Having said all that, today I'm running with a stock 280ZX distributor with an MSD 6AL (the L means it has a rev limiter that kills spark above a preset rpm). If I were to build another car, I wouldn't bother with the MSD and instead would use the stock electronic ignition module, or the GM HEI modification (others have done excellent write ups on that so I won't cover it here.) I'd take the money saved and use it to buy better tires or brake pads

[240ZGL]

I have the Pertronix 2 in a Mallory dual point and it uses a low resistance coil, .6ohm.

[xray]

I have the Pertronix 2 in a Mallory dual point and it uses a low resistance coil, .6ohm.

I checked the Pertronix site, and they didn't list an Ignitor II for the 240Z, but had one for the Nissan Patrol..is that the one you got?

Where'd you pick it up?

Thanks,

Steve

[red_dog007]

I haven't installed it yet, but I went the 1980zx distributor with the E12-80 (or is it E80-12?) module. Going to be buying a flamethrower coil to go with it. Should be a nice little upgrade.

Spent a little over $120 all together on this I think, and got a very nice rebuilt distributor.

In 3 weeks or so I can let you know how it does though.

I thought that the 240z only had the Ignitor I?

[ozconnection]

What a great summary Daniel (240Zman)! There isn't much more to add to this except that I have used the Crane Cams XR700 conversion kit and had great success with it. It was the first unit that I used to replace my stock points setup which were regularly mucking up.

I too am running a 280ZX electronic distributor with an MSD 6BTM which has a rev limiter as part of the unit. This is an advantage in that it prevents an engine over rev. by dropping out random sparks to the spark plugs. Different 'pills' are available so that you can determine how high the rev. limit is set. The other advantage of using the MSD in the ignition setup is that there is a whole range of products that can be used with it. I bought a window switch so that things can be turned on and off via the 'pills' that you install into it ie water injection,intercooler fans, water pumps etc etc etc.

Have a look at the MSD website or order a catalogue and have a look. The book is a great read and will teach you a little more about ignition systems and what's out there.

Cheers

Mark.

[240ZGL]

The Pertronix 2 that I have is not in a stock 240 Z distributor, it's in a Mallory dual point distributor. I wanted a top notch distributor which would be a Mallory but without the UniLite trigger. I don't trust the UniLite tigger. There sensitive to voltage spikes and can blow out. Besides I'm going to be running triples and we all know that the vacume

advance is useless with that setup and I'm not just going to disconnect that advance and try to work around it. I have mechanical advance, magnetic trigger, and a well build distributor housing. I have used Pertronix in cars with really beaten up wiring systems and have never had one fail.