Installation of Marelli Distributor Questions

[Chipps]

I have found quite a few discussions of distributors, but none answer the questions I have.

First, how do you determine the correct orientation for the rotor so it is pointing at the number one cylinder position for the installation of an original Marelli distributor in a 1973 Spider? Everything I have read says to find a tick mark, an indentation, on the lip of the distributor body when the cap is off. I see no such mark. The only photograph I found shows some other model distributor. It has the mark.

Second, I am told that the key at the bottom of the shaft of the distributor is offset. In other words, one side of the shaft is thicker than the other. When I measure this, they seem the same to me.

Third, how do I know the distributor is all the way down? In other words, so the key is completely seated at the bottom.

[GTV4EVR]

It isn't that one side is thicker than the other, it's that the key isn't in the center.

[Chipps]

Perhaps I phased it poorly. That is what I meant. However, when measuring it does not seem so. Is the difference very large?

[Roadtrip]

I believe the distributor will only seat fully against the block if the keyway engages the oil pump drive. The body of the distributor should be initially positioned with the black wire from the coil going into the dizzy body towards the rear of the car. If oriented correctly, the rotor should point towards the front of the car when hitting the #1 cylinder cap terminal.

[ghnl]

The offset is not huge so it does require close observation to make note of it. It may be more obvious if you look at the drive piece in the block (it is driven by the oil pump shaft which is driven by a gear off the crankshaft).

Below is a picture I snagged off the web from this page. I think you can make out the offset in the drive gear shown (it is a Bosch distributor).