Caution! Do not use a pointed instrument to avoid damaging or scratching the spark plug threads or the valve seats.
Check the head for damage or scratches and replace it if necessary.
Check there are no mineral deposits or rust in the head water cooled jacket; clean off if required.
Use a checking ruler and a thickness gauge positioned diagonally to the ruler to measure the cylinder head distortion.
- Maximum cylinder head distortion: 0.03 mm (0.0012 in)
Check that the tappet covers and the camshaft toothed wheel cover are not damaged or worn; replace the defective part(s).
Installing the overhead camshaft
The camshaft refitting procedure is described in the "Timing" section.