Reply to "Duraspark Ignition Question"

Scott,

Duraspark modules are identified by the color of the plastic wire "strain relef" where the wires exit the aluminum module housing.

I have never run across a Duraspark module with a black strain relief (they all had black connectors). The Duraspark II modules I am familiar with all utilized a "ballast resistor" in the form of a resistance wire in the primary ignition circuit. Not the coil. It was part of the cars wiring harness.

The Duraspark I modules had a red strain relief and had no ballast resistance anywhere.

The Duraspark I coil had a primary resistance of 0.5 to 1.5 ohms in 1977, 0.71 to 0.77 ohms in 1978.

Duraspark II coils had a primary resistance of 1.0 to 2.0 ohms in 1977 and 1.13 to 1.23 ohms for 1978 and later.

The ballast resistance for Duraspark II systems was 0.7 to 1.7 ohms in 1977 and 1.05 to 1.15 ohms for 1978 and later.

This info should be good for Duraspark modules having strain reliefs in the following colors: red, blue, yellow, white, brown.

Modules with a green strain relief are pre-Duraspark modules installed in 1975 and 1976 vintage Ford autos.

The Duraspark I module is the most robust module, it produces the fattest spark. However the Duraspark II module with the white strain relief featured a "cranking retard" mode which is ideal for cars equipped with hot camshafts that rquire a lot of ignition advance at idle.

your friend on the DTBB