Marelli Distributors

[chris_seven]

The early 911T was fitted with a Magneti Marelli S112AX Distributor and later engines has an S112BX distributor.

I can't find any reference in the Workshop Manual that defines which dizzy is fitted to which engine.

I would also like to understand the difference in the two types as the Manual seems to show they have the same advance curve.

[JJ 911SC]

This might help, from a for sale advert on the Early 011S Registry:

1965-69 911 S112AX Distributor for early 2.0, 2.2 and 2.4 and 914-6.

[JJ 911SC]

From my buddy in Montreal (years vice engine type): Marrelli type number?

[Flat6pac]

The shaft size will be different for the 2.4
Bruce

[chris_seven]

Even more confusing

I am not sure any Marelli Dizzies other than the S121B was fitted to a 2.4.

The link to the other thread says that the S112AX and S112BX are identical apart from the curves.

This doesn't seem correct as the Workshop Manual shows the same curve for both types.



It looks as of the AX was fitted to the normal T engine and maybe the BX was fitted to the T-C engine which I assume was emission controlled??

[JJ 911SC]

On this page, they got both the AX fitted to 2.0 and 2.2 and BX fitted to 2.0 Liter but also have the BX fitted to a 2.0: Porsche 911 Distributor - Motor Parts for Sale


These guys refurbish and sell parts for both model, they should know which fit where; https://www.************.com/p-993-distributor-re-build-service-marelli.aspx

[JJ 911SC]

Slow day at the office

Originally Posted by Alan.UK

In case it helps I think that is a 2.4 Marelli. There should be another digit at the end, if there is 1=T, 2=E and 3=S.

The Marelli from the 2.0 & 2.2 do not have a vacum advance. My book says the 69 version is Marelli S 112 AX and from 1970 Marelli S 112 BX.

HTH

Alan

[chris_seven]

It looks as if the AX normally has a condenser fitted and the BX doesn't so does this mean it was used with HKZ boxes ?

The BX seems to be commonly used on the 914-6.

I was, of course, wrong about Marelli Dizzies on 2.4 engine but have never seen one fitted.

The part Numbers used on the 2.4 were:

911T 5 010 974-1
911E 5 010 974-2
911s 5 010 974-3


They were also used in early 2.7 litre engines with the same advance curves and the same manual says they were used on the 2.7 Carrera with a different curve.

[JJ 911SC]

From the PETs, they had 4 versions (last 3 with Vacuum Unit)

901 602 022 00 (69 & 73 PET): 68 911 TU and 70 S, T, SPM,

901 602 023 01 (73 PET) 70 911 T, T-V
901 602 028 01 (73 PET) 70 911 E
901 602 032 01 (73 PET) 70 911 S