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Discussion Starter · #1 ·

The above linked thread starts with and explanation of options to replace the Marelli ignition systems (twin distributors, Digiplex and Microplex) with more adjustable, reliable and easy to service options. It is followed by a great discusssion and pictures. Electromotive HPX ignition systems are also mentioned as well as the dreaded tachometer issue.

Discussion Starter · #2 ·
Here's the post, since the

Here's the post, since the link does not work:

Since there has been some interest, here is some of my research on ignition replacement options for 308s and 328s. Will cover distributor based systems first

First it's important to know a few differences between the cars.
Early Euro 308s - Single distributor with twin points driving twin coils. Basically two distributors sharing a common cap. Late in the run there is a version of this single distributor with an electronic pickup (rare, sought after, and expensive).
American 308s - two 4-cyl distributors run by two sets of points in each distributor. One is specifically set to modify the timing for emissions purposes at slow running. Many folks simply disconnect these as they are not neccesary to run the car and can be a poop to set.
Fuel injected cars - here we go to Marelli electronic ignition driven by magnetic flywheel sensors. The 2v and qvs have 'Digiplex' systems with two seperate electronic control units (ECUs) firing a coil for each bank, which is partitioned out to the sparking plugs via a cap and rotor on the intake cams of each bank. The 328 and Mondial 3.2 updated to 'Microplex' with a single ECU driving both coils.

Aftermarket replacement issues:
This focuses on the little cam plug on the intake cam that will either drive a distributor as in the early V-8s, or three different rotor drives on the Digiplex/Microplex ignitions. It is important to note that the cam must come out for this plug to be changed. The 2v mounts a post drive for a now near extinct rotor (read $$$$) while the qv rotor post is different and the rotors somewhat more available (read $$). A popular option for 2v guys is to convert to the qv rotor and driver. The 3.2 liter engine is the most funky with the rotor held on by 3 screws into the plug on the end of the cam (TRs are similar). The caps on all of the electronic ignitions are the same.

Options out there:
1. The single Euro distributor pretty much bolts on I'm told to the same distributor drive as the US cars. These are available, but a bit dear, especially the Euro electronic triggered version (purchase sources: Steve Ahlgrim, Dennis McCann)
2. A popular addition which increases the life of points and improves the spark on distributor engines are boxes like Multiple Spark Discharge (MSD) units. These work to lower the current across the points giving them a much longer life, and yield longer sparking duration improving idle and performance.
3.Many points have been converted to optical triggers (e.g. Pertronix), replacing the points and usuall combined with an MSD or other driver. It's important to use a ballasted resistor with the coil if not using an MSD, as ALL optical triggers (Pertronix, Mallory, etc) are sensitive to voltage spikes.
4.The Ben Millermon Single Distributor Conversion Tampa resident Ben Millermon has pioneered a custom single distributor using a standard Mallory optical trigger with readily available caps and rotors (Search archives for details) There are many of these on 2v cars replacing the dual distributors and owners say they work quite well. These clamp on where the cap was and use the stock rotor drive post. Development problems centered around driving the tach, but he has a custom tach driver now. Cost around $500 without an MSD. While not yet commonly available for the funky 3.2 rotor mount, it is in development.
5. Norwood Performance Single Distributor. This Dallas Texas based Ferrari shop converts 2v distributor to an electronic trigger and somehow uses a Chevy cap. I think the cost is also around $500. They do not do these for 3.2s
6. Mallory Unilite distributor and Norwood adaptor. What Norwood will do for 3.2s is make an adapterkit for the Mallory Unilite electronic distributor for a flathead V-8 Ford. This plate bolts on to the head and attaches an offset drive dog to run the $238 Mallory distributor. The kit costs about $550 - $600

Distributorless Ignitions
If you want to keep your fuel induction but go to a distributorless electronic ignition, Electromotive make a unit for the Ferrari available from Nick's Forza Ferrari. It uses a magnetic sensor mounted on the front of the engine reading pulses from a ring that is machined onto the front pully or damper. Cost is about $1500 before installation. Nick sells the unit already modded for the Ferrari tach drive.

Tachometer drive
While we are on the subject, the Ferrari tachometer in the V-8 cars mentioned is really a 4 cylinder tach that is run off of one cylinder bank's coil or ECU. This is important if you are going to a single coil set-up. If you are unable to use the original sensors and ECU to drive the tach (will let you know in a couple of weeks) then you need to get a converter from Ben Millermon or have a reputable tachometer place convert the tach to a single coil signal.

Please let me know of any corrections or additions as this could all be wrong. Hope this helps.

UPdate #1
so here is update #1 to the original tome:

The Crane unit falls into the optical trigger category much as the Pertronix.

Here's the link to the new and improved Norwood website on the single distributor:
This includes an MSD, harness, block off plate and tach conversion - pretty much a straightforword parts swap for carb'd 308s with a couple of wires. Total price is $1495 + shipping. Installation would be 2 - 3 hours I'm guessing.

Ben Millermon's unit is much less expensive at $500. Same installation time, maybe a bit less. Not as clean as the Norwood installation, but simpler. Ben does not include a block off plate for the unused side. Adding an MSD 6AL box with an 8000 rpm limiter ($200) puts the whole she-bang at about $800 with incidentals I'm guessing.

Nick used to have more info on his website on the electromotive which I copied to my other computer - will try to get that for you if I can find it. The people that have it really like it, and it does give you the ultimate in control of the spark. Not sure how robust it is, there are some threads in the archives of those that have used it. It has a three dial-set pre determined break points and can have a MAP sensor for extra $$. The only mechanical concern I have is the mounting of the sensor and trigger wheel in the front as it looks pretty home made and can look pretty ricy if not done well (I may take some arrows for that, but why did they make it electric purple for Pete's sake?). Not sure of the costs over and above the $1500 purchase, would guess a few hundred bucks to install the trigger wheel. So I'm guessing total soup-to-nuts on this if someone else installs is about $2K.

Something I forgot to mention is you can drive the ignition with a programmable Motec ECU with input from multiple sensors and coil per plug setup, but I think the juice for the squeeze is getting pretty low for just ignition replacement ($$$$$$). This is one of those that is great if your'e getting some entertainment value from it. Personal opinion only here.

As to what's best for you - depends on what you want to do

As far as what's right for you, well it depends on what you want to do. If you're going racing, would opt for the Electromotive. If you are a street guy and want to increase reliability with a stock look would go with Norwood. If you are going for reliability, cost-effective simplicity and non-stock appearance is ok, the Millermon is the way to go.

Lenz Katronic:
I did not previously mention this $4K system as it actually replaces and combines the Kjet and ignition ECUs (keeping the existing twin coils and caps), but it does use the existing sensors:

This is just all my ranting here, and I'm happy we as Ferrari guys actually have some options. hope all of this research is springboard into making an educated decision

Discussion Starter · #3 ·
Mallory Unilite Single Distrib

Mallory Unilite Single Distributor / MSD installation on a 3.2 liter 4 cam

Well after waiting for months for the Elgin cams that never came, went ahead and installed the Mallory adjustable advance curve Unilite distributor using the adapter worked up by Norwood's (those guys rock). Placed an MSD 6AL system with 8000 rpm rev limiter in the trunk. Used new Taylor wires.

The reasons were 1. Reliability (the Marelli has gone single bank several times) 2. Ease of DIY maintenence (MUCH simpler to maintain and parts plentiful and inexpensive) 3. Ability to tune the advance curve (the Marelli is not user adjustable - max advance at WOT is 32 degrees).

Some lessons learned -
1. need to reverse the advance rotation for this particular distributor - Mallory, Inc did it for $25. The whole distributor, cap and rotor cost $250 (less than one OEM cap)
2. An MSD coil is not compatable with a Unilite trigger, but is compatable after MSD trigger box installed.
3. The original Marelli Microplex ECU will run the tach with the coils disconnected - how cool is that? No futzy tach adapter needed! Hooray!

Before I got there, Gary at Grand Touring (brilliant mechanic) took it out for a quick spin and said Jeez - this thing is too fast. Upon re-checking the advance, he found that it had inadvertantly slipped to almost 40 degrees by 3500 rpm. Yee-haa. He did not feel any problems, but discretion ruled the day and the advance is now set at an idle of 12 and max advance of 34 - 35 at 3500 rpm. He re-drove it and while it did not feel as fast as before, it was still quicker subjectively than when he had driven it with the stock Marelli Microplex. Then I got in to drive.

Wow! A different personality all together. It really wants to rev and rev!! Feels like it revs much much quicker and freely than before. Of course, will dyno next week to tweak and quantify what is really happening.. Maybe I should sneak it up to 36 degrees advance - I'm only running a 9.2 CR. There is a bit more advance brought in earlier, so perhaps that is what the difference is along with more total advance. Also, I have NOT opened up the plug gaps yet as recommended.

The pictures below show the raw installation - hasn't been prettied up yet as this was the development part. It's a bit messy right now, so work with me a bit... promise it will look better. The adaptor is the same red powder coat crinkle as the cam covers, the shade difference is that it is fresh - should mellow to match after some use. Have also included a wiring schematic. Will dress it up next week and take some better photos.

Original thread and photos:


best to all
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