Asking for a friend, seriously.
Engine with a four year old 6 volt Pertronics ignition suddenly starting to misfire only while running headlights.
Anyone have any experience with this or diagnostic advise? Thanks

 

I thought all Petronics came with a misfire or would work till you need it bad. The major issue it seems with Petronics is their modular taking a dump, but I haven't heard anything much on 6 volt systems. And when that does happen it's like a toggle switch has turned the juice off completely What you describe sounds like you may be having a low voltage issue, might check your coil or condenser or even the negative ground wire... Tedd

 

My money is on voltage drop with the lights on. Do you still have a generator? I would suggest checking input voltage at the Pertronix with the headlights (and other power draws, like heater fan) on.

 

Yup, lack of electron flow. Check the generator output.

 

OK guys, thanks for the quick suggestions. Gonna have to do some more testing.
Still running a gen., those are fun to diagnose.

 

Speaking from experience with pertronix (2 of them actually), I would throw the pertronix in the trash and put a good set of points and condenser back in it.

 

That was my suggestion on the outset, but he proclaims that it ran perfectly for 4 yrs. w/Pertronics. It would be nice to find the culprit in case the electronic ignition is not the problem, but yeah I agree.

 

While I'm no fan of Pertronix, if the car runs fine except when there's a large voltage draw (as in the headlights are on), then the Pertronix is not the problem. Changing things that are not the cause of the issue is a great way to unwittingly introduce new and creative failure modes. Find and fix what's wrong FIRST. Low voltage with points will still make the car run poorly.

 

That is what I am thinking, to find the problem, ground issue whatever, as it does run with the Pertronics.
But I also agree that the points ignition is what I would be running in a flathead Cadillac.
I will report back with the results, make take a while. Geezer speed here and all that goes with that - doctors, stubbornness, aches & stiffness etc

 

A lot of those old voltage regulators can be adjusted for voltage, as well as amperage.
The Cadillac shop manual will tell you how.
Does he have a shop manual?

 

Keep a set of points in the glove box!

 

I have messed with 6 volt regulators when I went to an 8 volt system on a 46 Chevy pickup and though it will work, I had a hell of a time adjusting the regulator to 8 volts, very touchy or I was very inexperienced and young at the time...Tedd

 

Of course you had " a hell of a time" adjusting the 46 Chevy regulator to 8 volts.
That regulator was meant to be set at a maximum of 7.2 volts.
8 volt batteries were meant for Ford tractors, not Chevy pickups.

 

Pretty common practice in the sixties when old cars with 6 volt systems were everywhere and most of them had poor electrics by then. The old motor manuals showed the fix by adjusting the spring tension on the regulator. We did a lot of half *** repairs because of cost and necessity of just getting by...Tedd