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ratty38coupe

Burning up points.Need help.

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Converted from 6v to 12v and changed polarity (now neg. ground). Burning up points after less than 5 mins useage. Any suggestions??

Thanks.

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You probably need an ignition switch with two positions (start and run). You need a resistor in the run circuit so that you points only have 6-8 volts across them except when starting.

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As said above, did you check the voltage to points, shouldn't be over 6? The resistor needs to be a ballist resistor. And when you hooked up the new coil do you have the negitive side going to points?

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Ratty 38,

I presume when you switched the original system to 12v. that you also changed the condenser which is across the points in the distributor to an appropriate value commensurate with a 12v system? Not to put to scientific an edge on it but all these components are designed for the system in which they operate.

Rodger "Dodger" Hartley

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Some years ago in a discussion about ignition coils I was told there is no such thing as a 12 volt coil. When the auto industry changed over to 12 volts they never redesigned the coil, they simple put a dropping resistor in series with it to drop the other 6 volts. How true this is I don't know but it makes sense. As the other guys have said you will HAVE to put a dropping resistor in ahead of the coils' primary winding because you're putting too much current through the points. The wrong value or open condenser (capacitor) will make some difference in an already working system and cause excessive point burning but over many miles and hours of use. Your fault almost certainly is too low a resistance in the primary winding of the coil and the points are being asked to make and break twice the design current. The easiest place to find a resistor is the so called 'ballast' resistor used in Chryslers of the 60s before transistor ignition systems came on the scene. They were usually hung on 2 metal prongs on the firewall on the engine side of the driver's side of the car. It's a white ceramic square about 4 inches long and maybe 3/4" square. The ignition switch in a Chryco of that period places a short circuit across the ballast resistor when the key is pushed over to 'START'. This places the full 12 volts on the 6 volt coil and gives a really hot spark for quicker starting. When the key is released to the 'RUN' position, the short is removed and the resistor is again placed in series with the coil and drops the excess 6 volts of pressure. You might want to hook something up like this for your own ignition. Good luck.

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If the points are destroyed like you said, theres only two reason:

1. The voltage/current is to high over the points. Take off the plus cable to the coil. Insert an amperemeter. take off the distributor cable (to the coil) and turn the engine. I dont know what it should be on a 6V system but on a 12V about 6-9Ampere. About the same i think. Put the distributor cable back and start. For a 12V it will be around 4-4.5A. The coil must however be about 1,5ohm on the primary coil. You should have two resistors - i think. One for taking down to 6V and another for decreadsing the voltage when driving.

2. Condenser. Should be 0.25-0.35microfarad for 6V. If you have wrong/bad condenser the points will be eaten - if the condenser is dead the car is impossible to run (can be started).

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