Vintage Lambo Ingition Systems

This, posted by Doc on the big list, is so good I want it here to refer to.Thanks Doc! >> I don"t often post on this board, but I think there may be a few problems with this statment. First, Bakelite (named after the inventor, not the process) has an excellent dielectric strength, and if not used in too high a temperaure environment, without cracks or oil saturation, can provide excellent insulaton in high voltage applications. Hence, it"s use in the ignition system of many autos. The Phenolic compounds of the "70 are quite different from those developed pre-war, but let"s not get into that. Caps and rotors are injection molded and can be produced quite cleaply. What"s gone wrong with the Lambo (Marelli) market is limited demand=limited supply, and when a run of caps and rotors are made, I think (opinion here) that they keep the production run low to keep prices up. Same as the Muira, there was never enough to meet demand, even during the production days. Now, if you "load up a plug" I think that means oil fouled, but it could me fuel fouled (carbonized) too, which is rare these days. That would lead to a low resistance path from the coil, through the cap, rotor, back to the cap, out the high tension lead, to the spark plug and across the fouled portion of the insulator to ground. Electricity will always take the path of least resistance, and would not travel back up the wire toward the cap and rotor. If, on the other hand, there were a complete open in the circuit, then the voltage would travel back where it came from. This is know as reflection, and is studied as Time Domain Reflectometry. While this can sometimes cause touble for ignition systems, if the rotor was developed correctly, the reflection will be routed back through the high tension lead to the coil, and possibly ruin it, or at the least get it quite hot (gotta dissipate those calories somewhere). Marelli did design the rotor well, and reflections rarely cause cap failures, provided there"s no pre-existing cracks, or accumulation of dirt/carbon. The worst will generally be some carbonization of the contacts on both cap and rotor from additional heat during the reflected signal. I bought a Lambo V12 that had been running with an open lead for quite a while. I repaired the open, cleaned the contact on the inside of the cap, adjusted the points while I was in there, an replaced the spark plug. All is well and no permanent damage. I"ve also found similar situaions on GM HEI systems, that don"t do damage if the cap is not cracked. That system puts out a pretty good spark, but nimrods that have ignition problems have often installed the coil in the cap, then dropped the cap and put an invisible crack in it. The crack gets filled with debris that is a better conductor than phenoic (and air) and a "short path" is found for the spark. This leads to misfires. Summary: Keep your fire engine clean inside and out, don"t drop your cap or rotors (yes, they"re old, many heat cycles), maintain the ignition like the book says (or pay to). I use a Tektronix o-scope with a high voltage probe to do my own ignition analysis. If you find someone with a top of the line "Suntune" analyzer, have him hook up the ignition scope and look at the output. Reflectometry is an interesting science, and you can literally see the pulse and dissipation of the spark to each plug. May find a bad coil, wire, resistive plug cap or plug. Doc