New Coil vs. Old Coil - Replacement Ignition

If ign wire goes to distributer then the - wire goes there

If ign wire goes to distributer then the - wire goes there

sorry forgot to put brackets round -

If ign wire goes to distributer the the (-) goes there.

as you seem to have problems reading if the wire called ignition now goes to the distributor then this wire is the negative one as its going to ground via the distributor.

the wire that left well i suppose this one must be the (+) wire.

is this better??????????????????????

I think you missed the answer.

Depends on the replacement ignition circuitry you've installed to replace the 6V system. If you're staying semi-original and retaining the points and capacitor then these ignition contacts get connected to the negative lead of the coil while the positive lead connects to the positive lead of the battery, often through a ballast resistor and the contacts of the ignition switch. (Notice that both wires can be referred to as ignition signals.) If instead the points trigger a capacitive discharge ignition module, then you must refer to the company's paperwork.

I had totally forgotten about those old ballast resistors! Those old cars would use a resistor to reduce voltage to the coil during run, and give full battery power to the coil during start, when the starter was drawing the voltage down. If you ran the coil on full power all the time, something would go wrong, the coil probably would overheat.

You're right - something would go wrong - you would drastically shorten the life of your points. Coil would probably be fine at 12v all the time.

You do not say if you converted to 12V ignition coil and neg earth. What is the resistance of the coil primary winding, does the coil have an outside ballast resistor, Have you rewired the the ign system from the ign switch to the distributor, are you using a distributor with points ? What is the trouble you are having?

If you tell us the above, I can give propper advice.

jurie

no major problems, the system is 6volt neg. ground. the truck runs but this past winter decided to rewire under the dash and replacing all ignition parts such as coil, voltage regulator, starting solenoid, starter cable, plugs, plug wires etc. a major tune up, including rebuilding the carburator.

Mike

It doesn't matter.The coil is simply a transformer,with the primary and secondary ends attached to the case.I would however, match the capacitor to the coil used, to ensure proper spark, and install a ballast resistor in series with the coil, unless it has one built in (some do).

Some people might appreciate more dope, for instance, the old 6v coil is actually made for 4v and must have resistance in lead from ign switch. Using a 12v coil on the same wiring wil lead to hard starting but 12v coil that is supposed to be used with ballast resistor should not have resistance in wiring. I have come accros coils that were marked wrongly in the factory. To make sure, let the spark jump from coil HT lead to soft pencil-tip to ground. If the coil is correctly wired. the spark will flare out on the earth side of the pencil tip. By means of a simple relay you can cut the ballist resistor out while the starter is working to get much better spark while the starter is causing a voltage drop. Let us hear from the person who asked the question if this is any help.

jurie

I noted you posted in AACA , his answer was spot on.

yes he was, As usual some long winded explanations tend to turn me off. I wish people would read the questions twice before writing their disortations.