1970 240z, I have started removing all the tape from the wiring harness and finding all sorts of things under the tape. This thing is wired between the coils Pos. terminal and the one of the two terminals on the side of the alternator, the alternator has been upgraded to the 60 amp.

I can't get your picture to open up to get a closer look, but if I am right, it is a wire wound resistor the "box" should be ceramic and there should be an ohm rating printed on it, and possibly a voltage rating. That looks like a wire wound resistor-probably there to drop the added power from the upgraded alternator. I would have mounted(and probably arranged a clamped and compounded heat sink) it better than taping it into the harness-the nature of a wire wound resister is they get hot.

Edited July 29, 201212 yr by hls30.com

Can you post what is written on the device? From the glare/lack of clarity, I can only make out that it's rated for 10 Watts.

Also, if you have an ohmmeter take two measurements. Put the positive lead on one side and the negative on the other, then another reading with the leads switched.

Edited July 29, 201212 yr by SteveJ

Upon further review, it kind of looks like a diode on the right side of the picture in series with the resistor.

I completely missed the diode in the small picture-but there it is in the bigun!

It is ceramic and there is a diode to the right, 10w is all I could make out too even with a magnifying glass the rest has worn off.

P/O assured me the resistor had been removed (I guess not)and it was a modern Pertronix system, the distributor does have the Pertronics pick up and the coil is a 3ohm Flamethrower, and the car does run very well.

Electronics aren't my strong suit, so I would have to get an after market ignition system like MSD or Crane to upgrade from the resistor?

Thanks,

Chris