Re: 12 volt conversion on 1940 110 coupe

Posted by HH56 On 2019/5/17 19:01:42

I believe the 40 temp gauge is mechanical so not an issue but if the oil gauge is electrical it and the fuel gauge probably need a reducer. A Runtz device would be better than a straight resistor as it provides a more stable output voltage but downside is each gauge needs one of those. Heater motor needs a resistor and for the best coil efficiency, you want the terminal connected to the distributor to be the same as the ground. In other words, if you have 12v negative ground you want the negative terminal of the coil connecting to the distributor. If the coil was changed to a modern type 12v coil it is easy to do but if it is the old style coil with the armored cable it is difficult and the increased efficiency may not gain that much when running 12v for the amount of effort. There should also be an added ballast resistor in the wire feeding voltage to the coil if you are running 12v. Modern coils can either have the resistor built in or else an external resistor needs to be added in order to protect the life of the points.

A suggestion would be that you might think about having the starter itself converted to 12v. The 6v motors do turn fast so engines start quickly on 12v but there have been some who have done the conversions and kept the starter motors stock and then came back on the forum to report their starter motor had been damaged when the nose casting cracked or was completely broken off. Consensus is the increased torque and speed of the starter running on 12v causes the pinion to slam into the end of the casting with such force that the casting eventually gives up.