A Quick Word About........Flywheels and Timing Marks

Back in 2002, having dropped in a new three-finger clutch, Mick Groombridge had wondered whether my 'clutch snatch' problem might be down to the clutch being married to the wrong type of flywheel. By this time he had reassembled the car and it was too late to check again!

When I'd brought the DX2 engine back home, one of the first things I did was count the teeth on the flywheel: 95 This was VERY useful information........

From October 1969 (so for the 1970 model year), the flywheel was changed from 95 teeth and from then on had 123 teeth. 95 teeth on the flywheel, told me that either:

• the DX2 engine was pre October 1969 - i.e one of the first DX2s from 1968/9  (which from other clues I doubted) or;
• that, in dropping the DX2 in the DS instead of the DX, whoever did it had gone to the trouble of re-fitting the original 1968 flywheel. (This was far more likely).

95 teeth also told me that (once re-assembled) inserting a pin......... 

The hole for the timing pin is under the alternator mounting point

.........in the timing notch in the flywheel........... 

Timing Notch In The Flywheel

.......would show the firing point for number one cylinder i.e 12 degrees before TDC (top dead centre) *.

It was very helpful to know this for sure - especially as I am going to have to set the timing up from scratch.

Something else it was useful to be able to confirm: a 95 tooth flywheel marries to a starter motor with a 10 tooth pinion. Since my car had it's original Ducellier 6182A with 10 tooth pinion, it was good to know it was being used with the correct flywheel!

Told you it was all useful!

* Something to note if your DS is 1972 model year or later: initially - after the flywheels changed to 123 teeth - the timing notch continued to show 12 degrees before TDC. However, Manual 814 Op. 210 notes that the flywheel changed after July 71: from that point the notch in the flywheel corresponds to TDC i.e. zero degrees. 

Parts Manual 604 concurs:.the part number for the 123 tooth flywheel changed from 5 413 852 to 5 414 483 from 6/71 onward with the annotation that the timing mark is now 0 degrees.......