Issues with a 6 volt system

5

53_mercLuke

Member
I'm having issues with my 6 volt positive ground system on my 53 mercury. I plan on upgrading the entire system when I have the funds but for now I'm keeping it 6 volt. Anyways I wired up the car, not using a wiring harness, and the engine cranks but won't start so I checked for spark and got nothing, I looked at 3 different diagrams to see if I missed something but by the looks of it, its all in the right spot. If I hook up the distributor to the coil I have power to the ignition switch but still no spark. Since its positive ground the engine block has power to it when I checked just the spark plug in the block, it makes sense since the positive post is connected to chassis ground. Everything in the distributor is new, the coil is new and the plugs and wires are new. This is my first time dealing with a 6 volt system and definitely my first positive ground system. If I can get any help on why I'm not getting spark at the plugs that would be great. Not sure of i did hook something up wrong even though I traced where everything when on the diagrams. Thanks
 
The "+" post on the coil will go to the distributor. Us a temporary jumper and connect the negative battery post to the "-" side of the coil. If the engine starts, you have a problem from the battery to the switch, or from the switch to the coil.
 
53_mercLuke said:
If I hook up the distributor to the coil I have power to the ignition switch but still no spark. Since its positive ground the engine block has power to it when I checked just the spark plug in the block, it makes sense since the positive post is connected to chassis ground. Everything in the distributor is new, the coil is new and the plugs and wires are new.
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From reading this it seems like you may be a bit confused on positive vs negative ground. For all practical purposes it makes very little difference as long as everything is consistent throughout the system. With the positive ground system the power is still considered as coming from the battery through the ignition switch to the coil/distributors/plugs and back to the battery via the grounds. When testing voltage you need to be sure you are keeping the polarity correct. On the voltmeter, the negative probe is the power source and the positivity probe is the ground when checking a positive grounded system. Don't let the polarity issue confuse you!
 
When dealing with positive ground, the only practical difference is battery installation and ignition coil wiring. Battery + goes to the frame, and the coil "power" wire goes to the coil "-" terminal, and the coil "+" goes to the distributor. Everything else is exactly the same.
 
So I hooked up the distributor to the "+" side of the coil and the power wire to the negative side of the coil and still have no spark. I did the jumper wire from the negative battery post to the negative coil post and nothing, I know it shouldn't be this complicated but it sure is giving me a headache
 
53_mercLuke said:
So I hooked up the distributor to the "+" side of the coil and the power wire to the negative side of the coil and still have no spark. I did the jumper wire from the negative battery post to the negative coil post and nothing, I know it shouldn't be this complicated but it sure is giving me a headache
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At this point something is not right, you either have a bad coil or there is a problem inside of the distributor.

Have you checked the points to assure they are opening and closing?

Have you checked the resistance of the coil to see if it appears to be ok? (this will not assure you that the coil is in operating condition, but it will show you if it has a major internal problem).

These cars have a very simple ignition system, if there is power to the coil and the coil is functional, opening and closing the points should create a spark. You can take the cap off of the distributor and manually open and close the points with a screwdriver with the plug wire from the coil near a good ground and it will spark if the points and coil are working and electrically connected.

The condenser could also be a problem, but the coil should still throw a spark even with a bad condenser.
 

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How long since the car last ran? Has the distributor been opened or disturbed since it last ran? With the jumper from the battery still hooked to the coil "-" terminal, measure the voltage from the coil "+" terminal to ground and let us know what it reads.
 
Not sure when the car last ran, when I got it the engine was out an tore apart and the car only has 14,000 miles on it according to the odometer. I will try that tomorrow evening, I'll have to bring my multimeter home from work, so I will post what I get. And I have taken the distributor a Nd replace the cap, condenser, and points, everything spins freely.
 
It is probable that the points have a glaze or corrosion on them. When they close they don't ground the coil and allow it to function. Replacing the points will probably clear it up. If you have already removed the distributor there is no need to run the tests unless it doesn't start afterward.
 
Some new parts are crap or not designed for low voltage systems. Make sure your distributor rotor is seated and stays in place. Make sure your distributor is properly timed to the engine. The condensers now days are problematic. Some are open circuit right out of the box. The Echlin brand sold through NAPA were the best buy at one time but are all under the Standard Motor Parts banner now and could be Hecho in Mexico. I buy two or three just to get one that works now days.
 
I tested resistance between the + and - on the coil and have 0.4 ohms and then tested from the + to the tower in the middle and only came up with 9.2 ohms, is that what it should be reading? I know 0.4 is at the low end but alright.
 
I'm assuming that the readings are 0.4 ohms on the Primary and 9,200 ohms on the Secondary sides. I am not very familiar with 53 ignition systems, but thought they did not use a ballast resistor. The resistance needs to be around 1.5 ohms in the primary circuit, so it needs a 1.5 ohm 6v coil or around a .7 ohm 6v coil with a 1.0 ohm ballast resistor. But, that would not prevent the coil from generating a spark, it would just burn out the points much quicker (and possibility the coil as well). However it would not be the short term problem. There is most likely a problem with the points themselves or the wiring associated with them.
 
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