I wanted to add the procedure that I followed to refit the 4S6471 (Wico XH2836S) to my buddy's D4 Traxcavator in case it's helpful:
1. Set the pony at TDC on #1 cylinder on the compression stroke (left side as viewed from operator's station) with the valves NOT rocking. Mark the visible tooth through the mag mounting opening at 12 oclock for easy refererence
2. Remove the distributor cover and distributor rotor from the mag
3. Set the magneto with the M mark on the drive gear at the 6 oclock position. I used a paint pen to mark the tooth opposite along with a matching mark on the mag body, very easy checking that the gear was not out of position
4. Fit the magneto, using the distributor drive gear on the end of the magnetic rotor to tweak the rotor to engage the main drive gear with the camshaft gear
5. Turn the crankshaft in the direction of rotation in order to center the distributor drive gear bevelled teeth at the 12 oclock position
6. Install the distributor rotor with the timing mark on the rotor periphery at the 6 oclock position, meshing with the drive gear teeth
7. Install distributor cap, and plug in the spark plug wires with the # 1 cylinder on the lower left 7/8 oclock position. The cap is marked with the #1 cylinder on the top right side but this is inconsistent with the procedure above, unless the distributor rotor is installed with the timing mark at the 12 oclock position in Step 6