Changing the valve guides

• Calculate the clearance between valve guides and stems and check that they are within the specified limit, if not change any worn parts.

Changing the valve guides

1. Remove the worn valve guides using puller tool N° 1.821.176.000 (A.3.0641).

• Check that the outside diameter of the valve guides and of their seats on the head are within the specified limits and that interference is within the specified tolerance.

1. Insert the new valve guides using tool N° 1.821.207.000.

NOTE: The guide valves are supplied also with a 0.2 mm oversize on the outside diameter.

• Ream the inside diameter of the valve guides to calibrate the holes to the specified diameter.

Checking the valve springs

• Check that the "free" length of the valve springs is within the specified limits.

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

1. Using a torque meter, check that the characteristic data of the springs are within the specified limits.