Pertronix installation, X-flow

[DavidL]

Can anyone comment on the best way to install a Pertronix electronic ignition in a Lucas distributor?

 

I'm the second owner of my 1990 Caterham, 1700 Super Sprint X-flow, with a Lucas distributor. As far as I can tell, the car was originally equipped with the Pertronix (the car was originally purchased from Chris T. at Sevens and Elans), but the old one failed because the wires to the Hall-effect sensor were abraided inside the distributor. The wires from the sensor have to do do 180-degrees around the inside of the distributor before exiting through a rubber grommet. The wires were pinched at that exit point by the plate the sensor sits on, and may have been worn down by vibration. The wires may have also been rubbed by the rotating magnet sleeve.

 

Has anyone run into this? Possible improvements would be to file a relief in the sensor plate for the wires, and to somehow clamp them down to prevent them touching the rotating parts. From staring at diagrams, I'm assuming that the centrifugal advance does not move the top plate of the distributor, but rather the cam, is that right?

 

Thanks for any advice, -David

[11Budlite]

David - I run an Aldon-modified Lucas distributer in my '64 MGB with a Pertronix Ignitor electronic ignition. I'm not sure how similar the setup is in your car but maybe this can help. The top plate is controlled by the vacuum advance assy and the cam is controlled by centrifugal advance weights and springs. Here's a photo of my distributor showing the location of the wires, sensor, etc. There is enough slack in the wires to account for the movement of the plate with the change in vacuum. Note that there is a ground wire that goes from the brass screw in the upper center of the plate to the lower left hold down screw.

[DavidL]

Hi Bruce,

Thanks, that's really helpful. My wires run around above the top plate and exit at about 1:00 o'clock on your photo. I don't have a vacuum advance, so I think all the advance is via rotation of the cam, not the top plate. I'll also call Pertronix.

[bball7754]

Dave - Believe your Pertronix was installed incorrectly. I recently replaced the sensor unit in my Lucas distributor (also for a Crossflow), and my wires were routed the same as Bruce's for his MG distributor.

 

It really doesn't make much sense to have the wires up top - just asking for trouble with the rotor spinning around.

 

Steve

[DavidL]

To update this thread... after much head scrtatching, and help from this community, I figured out that the base-plate in my distributor was installed 180-degrees out. I flipped it, and then the Pertronix unit installed the right way around, now looking like the pic from 11BudLite. Because there are 4 magnets on the spinning magnet sleeve, and the baseplate moved 180-degrees, the timing did not change (would not have been true with points). Thanks everyone.

 

However, the timing, measured with a timing light, is wacky. It idles (600 rpm) with 20-degrees of advance (way too much), and doesn't move much with wider throttle. I checked that the timing marks were right by finding TDC on #1 by sticking a plastic tie wrap into the cylinder with the plug out. Hmm, maybe the advance mechanism was also installed incorrectly.

 

Thanks for the help, -David