Morgans wrote:
"mindenpilot" wrote


We do all kinds of little tricks like putting a notch in the crankshaft to
use as a phase reference.
Then we can determine at what point in the cycle an anomaly occurs, which
can lead to different diagnoses.


How does the notch help in telling the rotational position?

It adds a known vibration to the system? ;-)

Presumably, it gets used as a timing mark of some kind. I guess that
monitoring the spark time to the No 1 cylinder would almost give you the
same. "Almost" because of course the spark can be advanced/retarded.

Frank