OSCA 1600 GT Flywheel

OSCA 1600 GT engines are approaching 50 years old and shared many common Fiat parts of their era.  Thus, the metal fatigue and often poor servicing on these cars has produced many engines needing refresh.  One of the most important replacement parts is the flywheel and it can be confusing as to which flywheel version to use.

There are two types of flywheels. See SGR 3 of the Fiat parts book:

1. 1959 to 1961  Fig 8/ 4045614  (A =66mm hole spacing for flywheel bolts)
2. 1961 to 1964 Fig 8A/ 4063348 (A = 64mm hole spacing for flywheel bolts)

The type  1961 to 1964 has bigger mount holes for the bolts that have sleeves, see Fig 10A /4063299 — while the 1959 to 1961 does not Fig 10/ 4046078.

The correct flywheel for the OSCA 1600GT is the 1961 to 1964 version (64mm hole spacing for flywheel bolts).  I STRONGLY urge all 1600GT owners to replace the flywheel bolts and save the original FIAT stamped bolts.   We have found that the flywheel bolts will stretch/bend over the decades and pose a potential safety issue.  The bolt specifications are: 9mm x 1.0 (thread) x 20 mm long.

The picture in the lower right is the flywheel WITHOUT the ring gear pressed onto the flywheel.

Leave a Reply