Turning of valve seatings

Turning of valve seatings

• If necessary, turn the valve seating using a suitable tool as follows:

• turn valve seatings with grinder at a 44° 30′.

• turn valve seatings with grinder at 20° and at 75° as indicated in the figure until the prescribed value "L" is obtained.

• After turning, grind each valve in its seating as follows:

• spread the stop limit surfaces "A" and "B" of the valves and seatings with abrasive paste (SIPAL A-REXONS Carbosilicium for valve).
• lubricate the valve stem with engine oil.
• Fix the lower surface of the valve head to the suction cup "C" of a pneumatic lap.
• insert the valve into the respective guide and grind.

• after grinding, clean both the valves and their seatings thoroughly.

Valve springs

• Check that the "free" length of the valve springs falls within prescribed limits.

NOTE: The planes must be parallel to each other and perpendicular to the axis of the spring with a maximum error of 2°.

1. Using a dynamometer, check that the spring's characteristics fall within prescribed limits.