I have always read that the 27degrees advance mark is the RED one (I have a 914 1,7 -72) and was happy to find it at once when timing my engine for the first time. However the car run badly, bad idle and bad response. After a lot of work and re-timing I discovered a second RED timing marg 4,5 fan blades from the first one. Both marks are visible only at the rear of the timing hole i.e. hardly impossible to see.
After re-timing to the new mark my now car runs perfect - you never stop learning...

/Lars S

1st red timing mark found


2nd red timing mark found

Some have a zero and 27, others only have a 27 and others only have zero! You MUST quantify this, it can melt an engine!

The first looks like it is only a paint mark. The second looks like a notch that is also painted.

The 2.0 fans I have seen had a "0" stamp (not that deep) at TDC and the red-painted notch at 27 BTDC.

--DD