Hydraulic tappets - operation check

Engine in-car repair procedures / Hydraulic tappets - operation check

3 Run the engine until it reaches its normal operating temperature. Switch off the engine, then refer to Section 6 and remove the camshaft cover.

4 Rotate the camshaft by turning the crankshaft with a socket and wrench, until the first cam lobe over cylinder No 1 is pointing upwards.

5 Using a feeler blade, measure the clearance between the base of the cam lobe and the top of the tappet. If the clearance is greater than 0.1 mm, then the tappet is defective and must be renewed.

6 If the clearance is less than 0.1 mm, press down on the top of the tappet, until it is felt to contact the top of the valve stem (see illustration). Use a wooden or plastic implement that will not damage the surface of the tappet.

10.6 Hydraulic tappet operation check

7 If the tappet travels more than 0.1 mm before making contact, then it is defective and must be renewed.

8 Hydraulic tappet removal and refitting is described as part of the cylinder head overhaul sequence - see Chapter 2C for details.
Warning: After fitting hydraulic tappets, wait a minimum of 30 minutes before starting the engine to allow the tappets time to settle, otherwise the increased stroke may cause the pistons to strike the valve heads.