View single post by Tom Bradley
 Posted: 02-08-2020 02:19 am
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Tom Bradley

 

Joined: 07-15-2013
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discogodfather wrote:
Finally got around to pulling my distributor yesterday. Seems like it's a Lucas 25D that's had its vacuum advance converted to a Centrifical.

The original distributor was a 25D that had centrifugal advance and vacuum retard (at least with the Stromberg carbs). This one looks like it had the vacuum retard removed by the PO, which is very common. If this is the original distributor, then it also had some extra stuff inside the shaft that kept oil from leaking out when it was mounted sideways in the 907 engine. As far as I know, nothing else out there has that. It looks to me to be in good shape, so I would say keep it. As long as it is not leaking oil or the advance is not working, it should not need rebuilding. Just replace the o-ring and lubricate the advance mechanism if it seems to need it. Then check that the total advance is 17 degrees going from 1000 to 2500 RPM.

It has the Petronix ignitor.
I know not use the ballast resistor in coils that are 3 ohms, is that correct? The ballast resistor is only used with 1.5 ohm versions?


The ballast resistor and higher-ohm coil was to keep the original mechanical points from burning out. If you have a Pertronix 2 or 3 ignition, then you can go to as low as 0.6 ohm coil and get rid of the ballast resistor. If you have the Pertronix 1 version you probably need to keep the ballast resistor and a higher-resistance coil. Since I have the 2, I am not sure the exact numbers. If you check their web site, they should have specs for this. If you can afford it, I would switch to the 2 if it is a 1. Just fewer potential problems.

One thing to keep in mind is that, if you have the original tachometer setup, going to a low resistance coil will probably make the tach read high. So be sure to use an automotive engine analyser with a tachometer function to do the tune-up.