The 903 is still in process, but I wanted to share with you all what I am up to.
In order to install the 903cc engine from a Fiat 850 into a Fiat 600 you have to reverse the rotation of the bottom end. The top ends rotate the same direction. Chris Obert wrote a pretty good guide. The easiest way, I think, is to replace the timing chain with timing gears. The gears can be purchased from Exotic+Raceparts here or from Fiat Plus here. You will also need a spacer because the timing gears are thinner than the chain sprockets, which you can have a machine shop make or purchase here. Also, you’ll need to replace the front and rear main seals with non-directional or clockwise seals. Continue reading →
The 767cc engine and transaxle are ready to go back into the car. I’ve left them mostly stock; saving most of the modifications for the 903cc engine going in later. However, I will share with you what I’ve done to get them ready to go.
First, you’ll remember in Part 2 that I had done some work already to the 767. I added the oil pressure sender and gauge from a Fiat 850. I had the cylinder head cleaned and decked, replaced the Solex carb with a Weber 28 ICP 1 that I rebuilt, and replaced the 600’s distributor with one from a Fiat 850. Then, at the end of part 2, when I removed them, they were both covered in a 1/4″ or more of hardened oil and road grime.