Fiat Dino series 1 Timing Chain Sprocket bearing replacement

Been a while since I have done one but do not recall any special tools needed.
"Special tool" is a term that has different meanings for different people. Have a picture of the problem in question?

 

Picture says a thousand words.

 

A six-point ring nut. Never saw one before. Ferrari tends to use various 4 point ring nuts for which there are plenty of special tools.

I suggest you make one up from a six point socket and grind the material away to fit the 6 point ring nut. My experience says it won't last long but enough for one job.

 

Its been on and off several times with a hammer and punch and or chisel. Do the same. Once off the bearing retainers can either be cleaned up with grinder and file or replaced and then it will also be easier to either find a socket or fabricate one as described.

I am betting based on how it was done they are not super tight.

If you use a propane torch on the alloy around the diameter of the retainer it will make the job easier.

 

Ferrari and Fiat loved using 4, 6, 8 slot ring nuts. Many sources for them. Considering those nuts are rather important to the engine living I would get new nuts and order the proper tools. Superformance will have them you just need to measure up the size you need.
https://www.superformance.co.uk/246/accessories.html

 

They may have been installed with locktite. Heat from the torch will break down locktite.

 

If a dedicated socket is very expensive, a Walton tap extractor might work. It’s hard to judge the diameter of the nut from the photo. My largest extractor is 1-inch; the ID of the steel fingers is about 15 mm. A 3-finger extractor would work for your nut.

 

The largest Walton tap extractor is for a 38 mm tap (1-1/2") which is too small for your nut. You may want to try the suggestion given above of grinding 6 fingers on a socket with a matching outside diameter of the nut. It's not uncommon to fabricate a special tool for these unusual fastners. I'm sure Fiat made a tool for this nut; the problem is trying to find the tool today.

 

These are called ring nuts if that helps with your search.

 

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A 50-44mm ring nut tool might be be the correct size for you application. Unfortunately, the Ferrari tools that are available are all for 4 slot ring nuts.

 

One final comment; there is a 46mm 4-finger Ferrari ring nut tool: https://www.ricambiamerica.com/rnt-46-ring-nut-tool-46mm-1.html

If you grind off 2 opposite fingers; it would fit on your 46mm 6-finger ring nut.

 

Harbor freight 3/4 metric socket set has been quite useful for similar purposes, reduce the OD for bolts in a deep pocket, grind the entry bevel completely flat for low profile nuts, grind out tabs for ring nuts, machine off 70% of the socket to fit in low clearance application, seal and bearing race driver when you don't have the one that fits exactly, the possibilities are endless.

 

looks conventional righty tighy” from pics

 

You might also be able to use a vintage ~2" Williams hook spanner. That's what I use on the big locking nut on 458 coil overs; might work here if you need to get some leverage.

Ray