If your distributor has 4 lobes on the point cam, then its a double life, if there's 8 then its a standard dual point. It doesn't matter either way, pull the dist. and set each set of points VERY carefully to .018-.019
re-time the engine, throw you dwell meter in the bottom drawer of your tool box, and DRIVE. The dwell will allways be in spec, if you set the points as described. Ya'll have a nice day ,Dave
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From: therichardsonfamily@xxxxxxxxxxx
Does my dual point Mallory use one set of points to fire only 4 cylinders, and the other set for the other 4 cylinders? That would double the point life, right? Or does one set fire all 8 cylinders, and the other set fire all 8 - just alternating between each other? I just don't get how the dual points work.
It almost seems that the Chysler dual point in the FSM, has both points firing the same cylinder at the same time. That would be the reduction in current flow through each, right? At the same time, allowing a higher current flow on each fire. That set-up would also allow one set to be insulated while you check the dwell on the other with the engine running, right?
My Mallory looks as though one set opens when the other is closed. That would not allow a dwell check with one set insulated. Am I seeing that correctly? That is why I'm asking if one set fires only 4 cylinders.
I assume the advantage in pulling the distributor when setting the points, is that you can turn the shaft to be exactly on the lobe, thus getting a more exact gap. I'll need to open them up a bit, I'm at .014 while checking it installed. How many miles can I expect to get out of a set of points?
As always, thanks for all the help,
Dan Richardson
300L Family Heirloom
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From: sosmi@xxxxxxxxxxx
The dual point distributor, was designed for HI-PO applications. The Chrysler dual point, had 2 sets of points to handle high RPM, and reduce the current through one set of points, they also ran higher spring pressure to prevent point bounce at high RPM. Mallory came up with a distributor called Double Life, it also had 2 sets of points, but they fired alternately, and also" Doubling" point life. After many years, of racing and performance tuning, I've found, the best thing is remove the distributor, and adjust each point set to.016-.019 I prefer going on the high side, because the point rubbing block wears, and you loose the spec. quickly. Checking dwell, is a waste of time, because the point gap will allways be between .016-.019 The other thing you could do, is convert to electronic, with a pertronix kit.Ya'll have a nice day, Dave.
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From: therichardsonfamily@xxxxxxxxxxx
Hello everyone:
I have a '67 440cid Imperial motor that has a Mallory Dual Point (#ZC365HP) distributor on it.
Question #1 - exactly how does a dual point work? Does one set of points deliver spark to 4 cylinders, and the other set to the other 4? What is the high performance advantage to a dual point?
#2 - I don't see a way to adjust the dwell when the car is running - is that correct? I check the dwell, shut it off, pop the cap, and guess at the adjustment?
#3 - I thought the FSM said to insulate one set of points while checking the dwell on the other. If one set runs 4 cylinders, that won't work out so well. How do I check & adjust the dwell on this Mallory distributor? What am I missing here?
#4 - Do I set timing first, then the dwell? What are the correct steps?
This one is right up Uncle Rodger or Dave's alley (two guys that seem to have forgotten more than most of us will ever know about these things)!!!
Thanks in advance,
Dan Richardson
300L Family Heirloom
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