Technical End float / End play on 479CC Rebuild?

[ChiapC]

Well, I got lucky and the timing chain fits very snug!! Though it all has to come apart again. As I now have a parts book, I ordered NOW front bearing insert for the crank, so I'm not reusing my old one. Not that it was bad, I'd just prefer to do it right the first time!

 

[TeleSpeed]

Interesting conversations here! In my very lay person’s opinion, the front is the timing chain end.

For the record, my replacement front bearing did come with the grooves cut out for the timing chain and the recessed screw cavities. I had to specially order the screws after the fact, as my original bearing had the original FIAT bolts still.

Turns out, I won’t be using MOST of the parts associated that I purchased. Possibly including a timing chain, which may be another issue in itself. I also had to order a new cam sprocket, as mine was pretty worn, per my engine builder friend. I found an original new one, so I’ve got that going for me.

I bought my parts through FD Ricambi, who was adamant that there have never been any issues fitting these parts to a 479 engine. Now I need to send proof back. They are substantially different. See the attached pics!

 

[TeleSpeed]

View attachment 401431

This is the camshaft timing sprocket from my 1959 500N, series 2. I am certain it is original to the car because it only has 17k original miles and it is very obvious that the engine has never been apart previously. I assume that Fiat changed 500N timing sprocket sometime during production because it is thicker than the 14.14mm thick sprocket photographed earlier in this thread. Is this 15.87mm thickness the same as the 500D sprocket?