Distributor Rotor Question

You wrote "set screw", but the SPC shows a small headed bolt that passes thru that hole and threads into the cam end? Don't think that you have to worry about it falling out, but rotating relative to the cam is another issue. Is there any feature in the ID of the new black one (or on the male cam end) that would set the angular position (like some sort of flat)? (Although that new black one does seem to be what MCP is also supplying as 119396 = 115520, and they are the "official" older F part supplier.)

 

There is an indexing notch. You are correct, the screw threads into the cam extension.

The rotor was heavy enough a spring clip was not trusted. The factory installed rotors were even glued in place.

I guess the Chinese manufacturer forgot to drill the hole.

Mike, I would have no particular fear of drilling it. Just measure carefully. Might want to notify the supplier though. If they tell you to drill then they have some responsibility. I assume you have no drill press? If not find a wooden dowel that fits the rotor ID, clamp the dowel in a vise and carefully drill it. Have an assistant hold the rotor still.

 

Falling off is obviously not the concern.
The company in Italy has many if not most of their vintage products made in China.
Taking the advice of a parts man who has little Ferrari knowledge or experience and no hands on experience isn't a good idea. They cannot even fill my orders correctly. I am sure not relying on them for technical advice but hey.....good luck.
Ferrari did not screw them and glue them on for no reason.

 

Thanks for the pic -- is there an identical feature in the old green rotor ID? If the new rotor has a physical feature to set, or limit, the angular position = definite goodness, but I'd still tend to vote with Brian to drill the hole and use the screw. Doesn't have to be super-precise hole (although I'd use a brad point drill bit to minimize any potential "splitting").

 

I fully agree with this keen advice.

I lost a bank in the middle of a long drive years ago due to (as I eventually discovered upon getting the car home) one of these set screws backing out and rattling about free inside the distributor cap. Once free, this screw eventually got caught between the end of the rotor and one of the extending plug terminals. Since the cam continued to turn regardless, this impact force sheared off the internal molded shaft key of the rotor, as is clearly shown in the picture for post no. 10 above. Upon my discovery, the rotor was free-wheeling on the end of the camshaft.

In hindsight, I had always been nervous before over the potential for this screw to crack the (thought to be) fragile plastic rotor due to over-tightning. So, I had only been tightening this screw "snug" but intentionally not too tight. No more!

I now tighten the screw much more so than before, along with a dab of Lock-Tire on the threads. And whenever I am poking around that end of the engine, I'll habitually pop the distributor caps and double-check that they both remain tight.

(As an aside, I do wish that the 2Vi rotor design carried over to another 308 variant, or else to a common Alfa or Fiat, or whatever. The fact that they are unique to the 2Vi, combined with the laws of Supply and Demand, make these buggers to be much more expensive than they would seem to be worth).

DM

 

Yes, that certainly looks very compatible (and those extra notches not a problem), and the "crack" on the old rotor maybe shows you shouldn't overtighten the screw -- was there evidence of some threadlocker on the screw threads? I guess I just like having a place for the screw to be so it doesn't go missing forever .

I believe even F realized that they sort of made a mistake on that one as a note on the MCP website says that some of the late 308i-2V went to the 308QV rotor (which went back to the more conventional 308 carb rotor attachment).

 

Should have been. Over tightening is what cracked it.

 

That sucks that they aren't making them anymore with the hole... I mean yeah you can drill it, but sigh.

I just had mine off to replace the distributor seal and there was no evidence of any kind of sealer used on it, just the allen bolt.