Fiat 124 Spider - Page 72

FIAT 124 Spider
Engine Maintenance + Modification
72
The block mounted distributor on Spiders made prior to 1971 has approximately 5
degrees of fixed advance with a maximum of 29 degrees of variable advance. The
advance increases in a linear manner to its maximum at 3500 RPM.
The camshaft mounted distributor on the 1971-72 Spider has approximately 5 degrees of
fixed advance with an additional 24 degrees of variable advance. The variable advance
increases in a linear manner from approximately 0 degrees at 850 RPM to 31 degrees at
4300 RPM.
The 1974 – 1978 distributor has approximately 10 degrees of fixed advance with the first
(starting) set of points and 0 with the second (running) set (at 850 RPM). Normal running
occurs on the first of points, with centrifugal advance to a maximum 36 degrees at 3500
RPM. The running points are activated when full oil pressure is reached and the water in
the intake manifold passages begins to increase.
Dave Voss, a FIAT owner who took the time to disassemble and understand the
differences in the 1979-1985 vacuum advance (electronic) distributors, noted the
following:
Given the age of these distributors, and the high likelihood that swaps and rebuilds have occurred
along the way, your [electronic] distributor could be any one of 6 combinations:
47º total = 33º mechanical + 14º vacuum
43º total = 33º mechanical + 10º vacuum
33º total = 33º mechanical + 0º vacuum (failed or disconnected)
36º total = 22º mechanical + 14º vacuum
32º total = 22º mechanical + 10º vacuum
22º total = 22º mechanical + 0º vacuum (failed or disconnected)
The distributor top plate, under the rotor, is stamped with the degrees of mechanical advance. The
vacuum canister is also marked. Generally speaking the replacement parts available today are for the
49-state version and, unless pinging or knocking occurs during operation, the 49-state is appropriate
for all Spiders. The electronic system also fits earlier models and is often found under the hood of
many older Spiders.
To recap, ignition advance is a crucial concept in tuning. A recommended approach is to
set your engine “by the book” and, as you understand more about your vehicle and your
driving needs, begin to adjust “by the ear” or to the maximum advance. FIAT
distributors interchange easily between vehicles, so the advantages of an electronic
system on an older motor may be appealing, or using a single-point distributor on a mid-
year Spider.
9.5 Ignition Electrical Diagrams
Note: These diagrams are excerpts from the electrical system diagrams I have produced
for each FIAT Spider model year. The diagrams are available online at
http://www.artigue.com/fiat
.