 1973-78 FiatSpider
From 1973 through 1978, Fiat utilized a dual point Marelli distributor on the 124 Spider and the 131/Brava. Unlike more performance oriented dual point setups, the Fiat system operates only one set of points at a time. The purpose of this system is to provide different ignition timing under different circumstances. When the engine is cold, the advanced points are energized, providing a timing specification of 10 degrees BTDC. Once coolant temperature reaches approximately 60 degrees F, the thermoswitch closes, providing ground for the ignition mode relay which then diverts the flow of electricity to the retarded points. These provide a timing specification of 0 degrees. The wiring diagram below shows how the system is circuited:
According to the Fiat factory service manual ""This arrangement allows for compliance to emissions standards while providing for good operation during starting and cold running"". What we have in fact found is that if emissions are not a primary concern, these cars run much better if the timing is a constant 10 degrees BTDC. They start easier, idle better, make more power and get better gas mileage. This can be achieved by converting to single points, a very simple process. The following wiring diagram shows how the ignition system is circuited after modification:
The process is as follows: Remove distributor cap and rotor. Disconnect the wire that leads to each set of points. Tape the two wires back to the harness so that they are out of the way. Remove one of the two sets of points (it does not matter which one; flip a coin) and its attendant condenser, and discard. Now, with an 18 gauge piece of wire and the appropriate crimp-on wiring terminals, connect the wire of the remaining set of points directly to the negative terminal of the coil. Start the car, and using a stroboscopic timing light, set the timing to 10 degrees BTDC. Congratulations, you've just converted your Fiat to single points. Simple eh? And remember, this modification is legal only for racing vehicles which may never be used upon a public roadway.
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