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Installing MSD Blaster 2 coil with points ignition


Guest orange_mini

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Guest orange_mini

If you are thinking of installing an MSD Blaster 2 coil into your old school ride that has points ignition it is very important to read on.

When looking at your ignition system there is a bit of theory to look at also.

The ignition system runs on 12volts and has roughly 3ohms of resistance in it (1.5 ohms being the stock coil and the other 1.5 ohms being the ballast resistor). Using ohms law (voltage = current (amps) x resistance (ohms)). This makes the current of your ignition system 4amps.

You will notice your MSD Blaster 2 coil has an internal resistance of approximately 0.8ohms (my coil had this value) of resistance. When replacing the stock coil with the MSD item, the total resistance in the circuit then drops to 2.3 ohms making the current in the circuit 5.2ohms which is too high. If using the MSD Blaster 2 coil and MSD ballast resistor the total resistance is a mere 1.6ohms making the current 7.5amps which is too large and will cause the coil to heat up and make your vehicle run like a pig. [My vehicle would back fire and hardly run at the same point on the expressway whenever I drove to tech, which must have been when the coil had reached its limit temperature wise).

The correct way I found was to use the MSD Blaster 2 coil, with the MSD 0.8ohms ballast resistor and an aftermarket 1.4ohm ballast resistor which made my total circuit resistance 3ohms (coil: 0.8ohms, msd ballast: 0.8ohms, aftermarket ballast 1.4ohms = 3ohms).

This was then reinforced by the Technical Support at MSD Ignition in the USA when I wrote to them explaining the problem I had.

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