5-speed compatability

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Steve124
Posts: 8
Joined: Mon Aug 08, 2022 4:43 pm
Your car is a: 1972 Fiat Spider

5-speed compatability

Post by Steve124 »

Are all the spider 5-speed trans the same? I have a 1995cc motor and trans in my 1972 spider now and want to put back in the rebuilt original 1608cc engine. I have the original trans but not sure if the 1608 motor will mate up with the 1995 trans.
18Fiatsandcounting
Posts: 3780
Joined: Fri Mar 15, 2019 11:23 pm
Your car is a: 1969 and 1971 124 spiders
Location: San Francisco Bay Area

Re: 5-speed compatability

Post by 18Fiatsandcounting »

The outer dimensions and general layout of the transmissions are all the same, although there are minor differences in the gear ratios across the model years. Five different sets of ratios as I recall. The potential issue is the size of the bellhousing. There were two different sizes of bellhousings, one for the earlier 1438 engines with the 200mm clutch and another for all later models with the 215mm clutch. Why it matters is how the starter motor is positioned relative to the ring gear on the flywheel.

However, in your case, the bellhousing for a 1608 and a 1995 should be the same in terms of dimensions, and the starter motor location in the 2L bellhousing should be right for the 1608 flywheel. In other words, your plan should work. There are some added features on the 2L bellhousing such as the threaded hole at the very bottom for the bracket for the exhaust downpipe, but your 1608 engine shouldn't need this unless you have a 2L exhaust system. Probably an easy fix if something is needed.

In case you are wondering about swapping flywheels, the 1608 engine has 10mm flywheel-to-crank bolts, while the 2L has 12mm bolts. So, the bolt holes in the flywheel are different sizes.

-Bryan
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