49 ford 6 volt positive ground with pertronic ignition

[Habusailor]

This car is really hard to start when the engine is cold. The spark is weak while the starter is engaged but very hot spark once the engine is running. I bought the car with the electronic ignition. I have cleaned the grounds, any ideas from the experts out there?

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[Bill OH]

Using a voltmeter, I would check for voltage drop from the battery negative terminal to the starter terminal and from the battery positive to the case on the starter. The tests will show up bad connections, faulty solenoid switch and cables that are designed for 12v. Make sure you have 6v cables. Find a ammeter that will go over the starter cable while cranking to determine the current draw. If all shows good, you might consider an Optima battery - expensive, but has a long life and will give the starter what it requires. Make sure all of your connections are CLEAN AND TIGHT!!!! I am assuming that the starter is in good condition!!??

[JSeery]

Bill pretty much covered it, while you are attempting to start the vehicle the current draw is so large that there is little left over for the ignition.

[51 MERC-CT]

And of course you have eliminated fuel starvation as the source of the problem??

[Bill OH]

Another thought: I use 5W20 Mobil 1. Maybe your oil is to heavy?

[Habusailor]

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I think I have issues with current draw. Charlie just rebuilt the carb but I will test fuel pump output and vacuum too. After cranking, choking and pumping in different sequences it seems to be flooded. The car has been sitting for many years so I suspect corrosion on the electrical side. Thanks for all the input, this is why I love this blog.

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[JSeery]

I would start by assuring the battery, starter and ground cables are the correct size. It is very common for someone to put a auto parts store cable on these old vehicles and very few of them would carry the correct wire gage. 6v requires about twice the current compared to a 12v system and thus heaver gauge wiring.

[Habusailor]

The solenoid to starter cables are original so the correct size. I did put on a new cable from battery to solenoid that is a 0 or 1. I know it should be 00. First thing I will do is clean more terminals and grounds. I have learned over the years not to overlook the simple stuff and charge into the complex things.


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[50fordcoupeman]

Maybe check the air gap in the Pertronix module.

[4dFord/SC]

Originally Posted by Habusailor

The solenoid to starter cables are original so the correct size.

They may be showing their age.

[drolston]

If there is any green showing on the copper strands entering the connectors, or the copper strands are pinkish, the cable is probably corroded internally and should be replaced, even if it is the proper gauge.

[flatheadmurre]

Check voltage at the battery while cranking to...may be that the battery can´t put out enough amps and then the voltage drops...just saying before you tear the car apart.

[WABOOM]

Originally Posted by Bill OH

Another thought: I use 5W20 Mobil 1. Maybe your oil is to heavy?

You use 5w20 in a flathead?

[Bill OH]

Yes, I have used 20W since 1950 in a flathead and never tossed a bearing. Also used it in farm tractors, farm truck(59AB) and combine. And I used it in a 1980 Olds Diesel that ran to 119K when a collision did it in. Bought it by the barrel.

[JSeery]

5w20 is not the same as 20w. The "w" stands for "winter" rating, so the 5w is rated at the winter temperature rating and the 20 at the normal high temp rating.

[bullrunmotor]

My 6 volt pertronix on my crab distributor ran much better when I replaced the copper core wires with silicone and opened up the sparkplug gap another .005 . pertronix is not telling folks to replace the copper ignition wires for higher capacity silicon/carbon sires.

[BUBBAS IGNITION]

Six volt and positive ground can be pretty touchy with electronics, system has to be perfect to work and have NO voltage drops.......especially while cranking......I would suggest changing back to points on this situation ...

[tubman]

Originally Posted by BUBBAS IGNITION

Six volt and positive ground can be pretty touchy with electronics, system has to be perfect to work and have NO voltage drops.......especially while cranking......I would suggest changing back to points on this situation ...

Finally! Somebody said it. I've been holding my tongue. Thanks, Bubba!

[Habusailor]

Thanks to all and for sure bubba. My first step will be check cables and contacts, then go back to points and condenser. It's cold in Fargo but I can work in a heated shop but can test in cold temps.

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[Mike51Merc]

What coil are you using?
I have a 6V pos gnd Pertronix and had ignition troubles for a long time until I finally got the 0.6 ohm Pertronix ignition coil. Runs great, and sorry Bubba but I'll never go back to points and condensors!