I have just installed an Allison XR-700 electronic ignition along with a Delta MK 10B CD unit on my '76 BMW 2002. The results are great! Smooth engine response at all RPMs, especially around town, and quick starts. I also have the advantage of two ignition systems since the CD can be turned off to revert to the XR-700 alone.
The installation was complicated only by the question of where to connect the tach. By trial and error, it turned out to be the point where the black wire from the Allison is connected to the green CD wire. I connected the black wire on the car's ignition harness at this point, making a four-wire connection. The points wire now becomes the tach wire since it connects at the distributor connector for the points which are removed.
The Allison components are well-made, especially the optical sensor which has a built-in wiring harness. The light control disk is especially well-made. It is molded to fit the distributor shaft and will not slip as with the Megaspark disk.
I mounted the CD on the fender well just aft of the coil and the Allison unit on the firewall just outside of the distributor. Since all the wiring can be routed along the existing wires in the body clips, the end result looks very neat.
Author: Dwight P. Glen
When installing any after-market ignition system it is wise to keep the original components with you at all times. An error in installation or defective system might leave you on the side of a lonely road, thumbing through your Friends of BMW . . . You do have yours now, don't you? Tech Ed.
I cannot resist the temptation to answer the Tech Editor's question in response to my item in the November '77 Roundel. Yes, I do have the original ignition components in my car plus a timing light and an accurate tach/dwell tester. As a matter of fact, an error on installation of my Allison unit did put me out of service on the side of a lonely road and cost about an hour on the highway reinstalling the original ignition parts. I still have experienced good service from this unit both on my BMW 2002 and a Luv pickup that also functions perfectly after almost a year of service.
Dwight P. Glen