Early versions are painted black and can be identified by the single Marelli logo label in yellow, later versions also had a red type label with a production id as well as a round warning sticker labeled "90º C - MAX - 194º F. The rev limiter had its own yellow Magneti Marelli label. Last versions featured a blue Magneti Marelli label similar to the one used on the AEC104BK.
Next to the race type there was also an OEM version in unpainted aluminium finish and featuring a Raceplex label on the rev limiter. This version seems to have been sold as an aftermarket item.

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Magneti Marelli Distributor S125

Cars:
Dino V6 based cars with a Magneti Marelli AEC 101 or AEC 103 ignition

Variations:
 S 125 A - 15° (1967-1968): 3 cams, two sets of contacts, early Fiat Dino 2.0 Spider and Coupe
 S 125 AX - 15° (1967-1968): 3 cams, two sets of contacts, early Ferrari Dino 206 GT
 S 125 BX - 15° (1968-1972): 3 cams, two sets of contacts, Ferrari Dino 206 GT and 246 GT, Fiat Dino 2.0/2.4 Spider and Coupe
 S 125 C (1972-1975): 6 cams, two sets of contacts, Ferrari Dino 246 GT/GTS, Fiat Dino 2.4 Spider and Coupe, Lancia Stratos HF

The Magneti Marelli S125 was the default distributor for the Dino 2.0l/2.4 V6 engine, the 15° degree number after the type number denotes the maximum cam shaft advance. S125 A type distributors are the earliest type and were installed in early Fiat Dinos with a points and coil based ignition before the Dinoplex was introduced. S125 AX type distributors were installed in eary Ferrari 206 GT's. S125 BX are the most common type of all S125 distributors. The later S125 C also featured a 15° maximum advance, but this was no longer mentioned on the type label.

The S125 rotor turns counter clockwise. Turning the distributor clockwise will advance the timing, turning it counterclockwise will retard the timing.

S125 A, AX and BX type distributors have a three lobe cam with two adjacent set of points wired in parallel to reduce point scatter and enhance dwell at high RPMs.

S125 C type distributors have a six lobe cam and feature two independent sets of points for emission control equipped cars. In the emission control setup, the first set of points (R1) was always active, and the second set of points (R2) could be added by switching ground to R2 via a microswitch (which was installed on the left Weber carburettor) when no throttle was applied.When idling this setup retarded the idle advance by 5.5° (camshaft) for better combustion and cleaner exhaust gases.
S125 C distributors have the same body as S125 BX distributors but are easily identified by the second hole for the additional R2 contact terminal on the left of the distributor body.

For supporting the points based emergency mode in a Dinoplex AEC101/AEC103 setup, a 0,25uF capacitor was installed on the S125A/AX/BX body (two on the S215C) and wired to the points. The Dinoplex ignition itself does not require a capacitor wired to the points as it uses the points setup only to trigger an ignition. The original capacitor supplied by Magneti Marelli came in a brass colored metal enclosure which was embossed with the Magneti Marelli logo, a production code (as example CE29T, ES29S) and the specification 0,25uF and 500 Volt.

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