I have a fair amount of experience with the ignition systems on older Ferraris, Maseratis and Lamborghinis. I don’t really have much of a problem with breaker points ignition systems and have found that many attempts to up-grade from breaker points bring other problems. Correctly set-up ignition points can last 5,000 and even 10,000 miles. Also, using the points as “signaling” devices only, doesn’t deal with many other deficiencies with the distributor.
We have an old Sun distributor testing machine. It’s about 50 years old but it’s an indispensable aid in setting up distributors. Most of the older Lamborghinis that come in for “tune-up” work have, at best, improperly set-up distributors and at worst totally worn-out distributors. Most of them have incorrect or non functioning ignition advance mechanisms and the dual ignition points ( 4 points sets in some) rarely share the same dwell angle settings and are usually not synchronized correctly. You can tinker with electronic ad-on systems but if the advance curve or points synchronization are not right you are wasting your time, effort and money. We have become convinced, after over-hauling many distributors that had no signs of previous disassembly, that many of the Marelli distributors left the Lamborghini factory with incorrect springs and related parts in the ignition advance systems, The cars often had “flat-spots” when accelerating which was blamed on the carburetors.
Another problem with attempts at upgrading parts of the ignition system is that often the energy from MSD-type components is too much for the rest of the old style ignition parts causing rotors, distributor caps and spark-plug/coil cables to fail. One solution is to replace the whole system. We have modified MSD Billet Distributors to fit. In that case you can run all compatible parts such as rotor, cap, coil, amplifier and spark plug cables. MSD even sells an electronic adjustable ignition advance computer so you can disable the advance weights.
Even with the full MSD ignition system though, there are still problems. One is that above 3,000 RPM, MSD ignition amplifiers revert to single spark ignition. Except for emissions testing, what good is Multiple Spark Discharge if it goes back to single spark discharge just when you start driving on the fun side of the tachometer? Also any change or fluctuation in cam timing or lash in a distributor gear-set directly affects ignition timing control.
The best system to use is a crank-fired set-up such as what Electromotive sells. The long duration spark is initiated by a rigidly mounted trigger wheel on the end of the crankshaft. The spark goes directly from the coil pack to the spark plug and a fully programmable computer controls timing and spark duration. (Plug or cover the hole and throw the distributor on the shelf with your other relics.) All you need is a lap-top to make adjustments. Some time on a good chassis dyno would help to get the maximum performance out of your ignition system.
by Wil de Groot
Next tech tip=>MAINTENANCE