BMW 502 Race Preperation

Home
Map
Service
Sales
People
Performance
News
Conversions
Articles

<< 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 >> 

Electrical System---Engine Electrics

We started this project with three old but functional starters for the V8 and all three failed during the development work. Careful examination of these starters and comparison to starters from modern BMW engines lead us to the observation that the M10/M30 starter was very close to right. The bolt pattern for mounting to the engine was the same, the starter drive teeth appeared to be the same, spatial configuration of the solenoid seemed to be close enough that it might fit---everything, in fact, looked good except that the throw of the starter drive was a few millimeters too much. A simple 6mm thick spacer between the engine and the starter took care of that problem, and an M30 1.2 horsepower starter from an '80s era 5-, 6-, or 7-series bolted right on and it now cranks faster than the original ever did.

The stock distributor is another known problem area on the original car. It's two sets of points supposedly work together to give plenty of dwell time for spark build-up. In fact, a dual-point system takes a marginally reliable single point system and makes it half as reliable through the addition of another set of ready-to-go-out-of-adjustment contact points. Fortunately, the BMW Bosch distributor is similar enough to the Bosch distributor for a 60's Mercedes V8 that the Crane electronic ignition pointless conversion made for the Merc works perfectly in the BMW. No more points means much better reliability and easier tuning.

Electronically ridding ourselves of ignition points brings us halfway to a modern reliable hi-energy ignition system. Next we began work on the hi-energy part. The state of the art in racecar ignition systems these days is the Multiple Spark Discharge (MSD) high-energy system. I elected to use the MSD system and a matching coil, but, in a fit of insanity, I went further and we built a complete double system. We now have two complete MSD and coil systems that can be switched from inside the car. My meager rational for this extravagance was that with two systems we could switch from one system to the other for test purposes if we ever had an ignition problem. No diagnostic delays necessary. Call me crazy.  Hi energy plug wires and new cap and rotor from the Mercedes distributor complete the ignition system.

<< 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 >>