Regarding the ignition system ballast resistor and associated system.
I’ve spent way too much time studying and tracing the various DC circuits in our ’64 300K, but I thought it may be useful to some to try to explain and identify the ignition switch (IS)/ballast resistor (BR)/coil (C ) system. The wiring diagrams for our 1964 300K may be found at dual member John Holst’s most excellent website at: http://www.jholst.net/wiring/wiring.pdf The wiring codes below refer to that wiring diagram.
The object of the BR is to reduce the Voltage to the coil while the engine is running, thus extending the life of the ignition “points” and prevent their oxidation. Wiring and a separate power source are provided to route full Voltage to the coil while the engine is cranking. This facilitates a start, even with the lowered battery Voltage which occurs while the starter is engaged. Voltage drop across the BR will vary with engine speed with only one Volt, or so, drop at idle and more at running speed.as the required current increases. The resistance of the ignition resistor is specified at 0.5-0.6 Ohms so a 10-Amp coil current would produce a 5-6 Volt drop. The Ignition system current draw is specified as 1.9 Amps at idle.
· +12V power is hard-wired (through the bulkhead connector) from the battery to the IS at all times—no fuse or circuit breaker.
· When the ignition key is twisted to the “Start” position, the full +12V is sent from the “IGN 2” lug on the IS to a connector on one end of the BR (via J3-an 18-gauge Brown wire). The full +12V is then routed via a second wire attached to the same connector (J2A 14-gauge Dark Blue) from the connector to the + terminal on the coil. This provides the full +12V to the coil while cranking.
· When the engine starts or the key is no longer twisted to the right, power to the coil is routed from the brass “IGN” lug on the IS to the connector on the other end of the BR via a Dark Blue 16-gauge wire. A second wire (R5-Dark Blue, 18-gauge) is routed from this same connector to the “IGN” lug on the Alternator Regulator as a reference Voltage for controlling the alternator outlet Voltage while the engine is running.
While it does not matter which of the two connectors described above is fitted to which of the two brass lugs on the square-section white ceramic BR enclosure, the varying lengths of the two pairs of wires extending from the wiring harness will route each pair of wires to one or the other of the brass lugs on the BR. One of the two pairs of these ignition system wires consists of an 18-gauge Brown wire plus a 14-gauge Dark Blue wire. The other pair consists of one 16-gauge wire and one 18-gauge wire—both Dark Blue. Colors of the insulation on the wires lose their intensity and identity over the years, especially under the hood.
On air-conditioned cars there is a somewhat similar white ceramic-encased resistor within about eight inches of the BR. This resistor is used to provide low and medium speeds of the blower fan and has the same size connection lugs as the BR. The big differences between the two resistors include the blower resistor being a round, hollow, cylindrical ceramic case which has a single Brown 16-gauge wire (C4A and C4B-- http://www.jholst.net/64-service-manual/air-conditioning.pdf) connected at each end. These two Brown wires are not included in the main wiring harness but protrude, along with a light-blue 18-gauge wire for the A/C compressor clutch, through a separate grommet on the firewall. I measured the blower resistor’s resistance at 12 Ohms. It would take no great effort to mix the wires to the blower resistor and the BR. Don’t.
During my research, several interesting data surfaced. The 1964 Service Manual specifications show two different coils for Chryslers of that year: 2444261 on 361’s and 383’s. and 2444263 on basic 413’s. 413/390’s had 2444242 and 413/360’s had 2444241. This indicates there was some fine tuning of turns ratios and impedances for different engines. The Parts Manual shows the same coil on all MoPar cars except hemi’s 2495531. What’s sitting on top of your K engine? The 1963 Parts Manual shows the same coil across the board while the 1963 Service Manual shows four different coils with two different sets of spec’s. There is also a dichotomy regarding spark plugs. Ranging from J9y to J12Y and including an XJ9y and Xj10Y—but that subject could ignite another too-long thread. Sounds like the bean counters were doing the ignition engineering. Plus, the coil specifications are poorly presented and coordinated between the Service and Parts manuals. Interchange info: all Champion plugs with the X prefix: RJ12YC. Without the X prefix: j12YC. Informative magic decoder ring for Champion plugs: http://www.federalmogulmp.com/en-US/Technical/Documents/Champion%20Spark%20Plug%20Symbols%20Definitions.pdf or: http://tinyurl.com/zatv56a
Brentwood, CA (Rainy!)
John and Marshall,
Posted by: "Rich Barber" <c300@xxxxxxx>
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