agree ! — wow Carl , that is REALLY valuable info from a guy that has obviously been there . I did not know the relationship of points opening and rotor position varied so much within the body machining of various distributors ( and thus the clip location and in turn which tower is #1 ! I have encountered this in many flavors over the years and blamed myself ( must be oil pump drive is off one tooth etc) — and you really do not want to revisit that , so moved wires . Maybe why mopar had the red end (!) Not always the same tower across distributors…
On another related front , I have been working for a year on an electronic circuit that “ closes the points “ electronically , right after the spark far faster than the second set in a dual point . So single point (or dual with second removed ) will gain dwell ( and 1000 + rpm more before falling off—- , improved due to dwell increase at high rpm ,( ,why the 300 has dual points- they had same goal ) Are you aware that all electronic ignitions lose 1 volt in transistor, so net V to coil set up is say 12V instead of 13 , but energy in coil goes as 1/2 L I sq . 12 sq is144 , 13 sq is 169 , huge difference (the max current follows voltage) . Points make a hotter spark than any electronic (!) by a lot . Why John commented it runs great on single point , and rams pre JK no point going over 5 k . But single point spark energy starts dropping at about 3500,,still ok , but dropping as dwell time shortens But hemi another story , loves hi rpm hp , needs the spark . Had duals in 51! The problem with points is dwell is getting too short at high rpm for coil to “ fill up “ ( takes about .002 sec) . We are gonna fix that Better than dual points , while still keeping points ( so no punting common to full electronic either )
Most 300 dual point are not set right in my experience (in my own 300’s)
really hard to get right with gap measuring it moves as you tighten it , HAVE to use old style dwell meter . ( sears on e bay) Get it wrong it runs awful . Fighting with that hassle in back with hemi is my motivation ( aka dropped screw)
Hope you do like the idea! will fix all single point any brand.
soon , little box outside dist ! 6500 rpm no problem w single points , and no arc when they do close ( circuit is already closed!) No electronic pickup or mods either On Aug 1, 2025, at 9:16 AM, John Nowosacki <jsnowosacki@xxxxxxxxx> wrote:
Thanks for this explanation, Carl! Earlier this Spring I removed the dual point tach drive disty from my G to send away for rebuild, and purchased an inexpensive single point unit off of Rock Auto to use temporarily. I was being very careful noting where the rotor was pointed and at which spark plug wire tower as I switched distributors. I was surprised/confused while making the swap when I noticed I would have to have the plug wires 'offset' by one tower on the replacement single point unit as compared to the original dual point. I didn't bother to try and understand why, so I just put the wires where they needed to be and the engine fired right up and ran fine. I'm going to have to reverse the thought process when switching back to my now rebuilt original distributor. I must admit I've had my original back for some time now, but the car is running so well on the cheap $99 Rock Auto replacement (came complete with points/condenser/rotor/cap installed for that price), I haven't rushed to put it back in. Part of the procrastination was in trying to remember the direction of the 'offset' when I made the original swap, and not wanting to mess up and possibly go in the wrong direction going back to the original. Your post explains what I encountered and has helped to refresh my memory so I can more confidently go about re-swapping. ;-) It will be nice to see my tachometer working again in the console.
Didn't work as in doesn't start? Tach drive distributor (F I assume?). Still breaker points, correct? I have found that on this dual point distributor the #1 wire would go on the distributor cap tower that is the second one clockwise from the clip that holds the cap on. Looks like it's attached one tower clockwise (like a single point distributor or an electronic ignition, which has the vacuum can at a different angle than on the dual point). The engine actually doesn't care where the wires are on the cap, as long as the firing order is correct and aligned with the rotor properly. With the tach drive distributors you have to get the vacuum advance can aligned such that it is somewhere between the ram and the radiator hose. -if you are off by one tower in either direction (but correct firing order), the vacuum can will either be way back by the ram (retarded) or cocked way over to the right (advanced) and maybe hitting the radiator hose or the tach cable stretched too tight.. So, once you get the rotor in proper position for #1, figure out which is the best tower to start with #1. Sometimes two towers clockwise from the clip works best for positioning #1, but YMMV. Also, if someone installs a Pertronix electronic module inside one of these dual point distributors it will change the timing a lot and may require moving all the wires one tower clockwise. Make sure to set timing with vacuum advance disconnected and plugged - makes huge difference! - on G vacuum advance all in at idle!
Carl B. G and J
------ Original Message ------
Date 7/31/2025 1:42:08 PM
Subject Re: {Chrysler 300} Elementary ignition question
Well, that didn’t work. Grrr
I put my timing at top dead center so I could look at the rotor and see where cylinder #1 is. From that, I placed plug wires popped off #1. Going on the rotor turning counter clockwise, I placed plug wires #8 to the right of #1. Then followed the rest of the order according to the manual. The only difference is that I have a NOS cap on. What could I have wrong here. I am pointing to where I placed #1 wire.
Thanks for any guidance
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