Mallory Rev Pol Distributor


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By Richard - 3 Years Ago
I have a Mallory Rev Pol (reverse polarity I think) and the coil for it.
It runs two condensers to two separate coil polls. Inside the distributor is a four cam lob instead of eight.  I think it gets dual points.
To me it’s a bit confusing on how it works, and why was it considered high performance in its day. Any comments appreciated.
I would like to run it on my Y Block for nostalgia, I’m under no pretense of its lack of superiority to modern ignition, just wanted to be different and Ole School. 
I’m currently running a Mallory dual point, no vacuum advance, Mallory coil. Runs great.
By Ted - 3 Years Ago
Mallory Rev Pol distributor
The idea behind two sets of points and only four lobes was to increase the dwell time or saturation time for the coil which is advantageous in a high performance application where a higher rpm is expected.  One of the drawbacks of such a setup is that both sets of breaker points must be synchronized in their openings so that the ignition timing is indeed the same for all eight cylinders.  Having one set of points opening at a different rate will have four cylinders firing at a given crankshaft timing event while the other four cylinders will be having that timing event occurring either earlier or later depending upon the point gap setting.  A distributor machine would be the optimum way to set up one of these distributors.
 
FOOD  FOR  THOUGHT.
The one thing I have come across on one of those Mallory Rev-Pol distributors was one lobe being slightly off as compared to the other three.  What eventually led to this discovery was doing some detective work on an engine that was not running at its full potential.  The messed up lobe was ultimately found by checking the ignition timing on several different cylinders and then reaffirmed when putting that same distributor on a distributor machine.  Even when both sets of points were set exactly the same, there was still two cylinders having a different firing event than the other six.  At that point, the distributor was replaced with a different distributor and the engine performance picked up accordingly.
By Richard - 3 Years Ago
Thanks Ted,
I have a friend that can set this on his distributor machine I’ll save your comments.  If I understand your input then each set of points must be set upexactly right, the lobes should all mic out the same. I also think the distributor shaft needs to be dead straight, any wobble will change the timing.
defiantly not something to just put in place without seeing how it behaves on the distributor machine. 
Richard