Bang for the buck, the Duraspark II
is hard to beat as a triggering device for an electronic ignition system.
Coupled with either the stock ignition box or an aftermarket control box,
it is a tough, readily available, reliable distributor.
Ford began using electronic ignitions
in 1973 and introduced the Duraspark II system in 1976. The biggest
change, apart from the control box redesign, was the large distributor
cap to handle the increased spark energy. The system consists of
a magnetic reluctor and pickup in the distributor, and an ignition module
to trigger the coil. Typically, the distributors have both mechanical and
vacuum advance mechanisms. The curve is reset by using inexpensive springs
and adjustable advance units. They are found on both 200 and 250 engines
and are interchangeable.
They are a direct fit on older 200/250
engines built after 1964 with the 5/16" oil pump driveshaft. Pictured above
is a Duraspark from an '81 Fairmont 200 ci engine, installed on a '73 Maverick
250 ci engine. If you want to get one from the auto parts store,
make it easy on the clerk and just ask for a distributor from a '78 or
'79 Fairmont.
The GM Module
The Duraspark can also be very simply wired
to a GM 4-pin module for a very clean and easy setup. The black wire
from the distributor is no longer used. The module has to be mounted
on an aluminum or steel plate dissipate heat. Ground the mounting
plate by bolting it to the engine block or chassis.
You can use a cheapo $9.95 module or
a good aftermarket module for better spark. Any of the early mid
seventies to early eighties GM cars have this module.
This is an incredibly easy way to add
a Duraspark!
The Stock Duraspark Ignition Module
The stock ignition wiring diagram looks
daunting but all of the wiring is contained within the harness. This leaves
only two connections which have to be made: a red wire which is connected
to a switched 12V source and a white wire which goes to the start terminal
of the ignition switch. The white wire is optional. When used it retards
the spark a couple of degrees to reduce the load on the starter (an enterprising
hot rodder might hook this up to a nitrous switch to retard the spark when
the juice is on).
When selecting the module, the one to
ask for is the one with a "blue strain relief" or the "49 state" module.
Using an Aftermarket Control Box
The Duraspark distributor is
easily wired to an MSD or other aftermarket ignition system. The MSD can
be used as a stand-alone or in conjunction with the stock module.
Wiring with stock module
Wiring the MSD as a stand alone
Tuning
Spark plug gaps may be set much
wider with the Duraspark. Using the stock module, set plug gaps between
.045" - .060". With an aftermarket module, check the manufacturers recommendation.
On my coupe, I am using the MSD6A as a stand-alone with plug gaps of .054".
