Setting the Ignition Timing

Key slots and keys (wedges) are used in series production by the manufacturers in order to enable precise setting of the ignition timing.

The rotor is not fixed to the crankshaft using the keys which are only used for accurate fixing during assembly! If your PVL rotor does not have a keyway, this is correct from a design point of view and no key is used. Therefore, the rotor can be positioned on the lateral journal in the 360 crank angle range.

With rotors without grooves, it is better to align the stator as accurately as possible with the required position in order to avoid repeated withdrawal of the rotor from the lateral journal (PVL extractor tool required) and to push the rotor onto the lateral journal with overlapping marks only after determining the required TDC position.

A graduated disc or a dead centre measuring device (special tool) is used to set the ignition timing in order to measure the position of the piston before top dead centre (TDC). You can set the ignition timing to the engine by aligning the marks on the rotor and the stator in conjunction with measuring the piston position before top dead centre. If the stator is located approximately in the centre of the available setting range (slots on the stator plate), tighten the stator fixing screws by touch so that it does not move by itself but can still be rotated manually. Turn the crankshaft slowly in the direction of rotation until the piston has reached the required position before TDC (e.g. 1.6 mm).

Prior to rotor installation, clean the rotor bore and also the crankshaft lateral journal with contact cleaner, acetone or another suitable product in order to ensure that they are clean and free from grease, oil or other deposits. Install the rotor on the crankshaft so that the ignition timing mark on the rotor corresponds to the mark on the crankshaft, see recommendations in Table A.
Many PVL stators have marks for both directions of rotation.. Ensure that the correct mark for the direction of rotation is selected for your engine!

The following applies with rotors with grooves:
Put the rotor onto the lateral journal key to fit exactly in the groove. Place the nut by hand on the rotor. If the piston is in the required ignition position before TDC, turn the rotor until the marks on the rotor and stator overlap. Screw the stator down and tighten the rotor nut with the required torque specified by the manufacturer.

The following applies with rotors without grooves:
Put the loose rotor approximately in the position where the marks on the rotor and stator overlap and place the rotor on the lateral journal in this position. Tighten the rotor nut and screw with the required torque.

If the mark on the stator is covered exactly by the mark on the rotor, the ignition timing is set correctly. Check the ignition timing.

Position the piston again in the required position before TDC and check that the marks on the rotor/stator still correspond. If not, simply loosen the stator fixing screws and push the stator so that the marks correspond, tighten the stator screws again correctly.

If the marks cannot be aligned with correct TDC position of the piston, it is mostly due to incorrect rotor position (with rotors without grooves) and the rotor must be removed from the lateral journal using the PVL extractor tool. The setting procedure must be repeated.

It is helpful to put marks on the casing and rotor with a permanent felt tip pen.