SOHC engines
1 The valve clearances must be checked with the engine cold. On carburettor models remove the air cleaner.

2 Disconnect the HT leads from the spark plugs and release them from the clips on the camshaft cover.

3 On fuel injection models, unbolt and remove the bracing strut securing the inlet manifold to the right-hand side of the cylinder head.

4 Where applicable, unclip any hoses and wires from the camshaft cover, then unscrew the securing bolts and remove the camshaft cover and gaskets. Take care not to lose the spacer plates which fit under the bolt heads, where applicable.

5 Numbering from the front (camshaft sprocket) end of the engine, the exhaust valves are 1, 3, 5 and 7, and the inlet valves are 2, 4, 6 and 8.

6 Turn the engine clockwise using a suitable socket on the crankshaft pulley bolt, until the exhaust valve of No 1 cylinder (valve No 1) is fully closed; ie the cam lobe is pointing vertically upwards (see illustration).

23.6 Cam lobe correctly positioned for checking valve clearance. Insert feeler gauge as shown by arrow

7 Insert a feeler blade of the correct thickness (see Specifications) between the cam follower and the heel of the No 1 valve cam lobe. The feeler blade should be a firm sliding fit. If not, loosen the locknut and adjust the ball-pin position accordingly by turning the adjuster nut, then tighten the locknut (see illustrations).

23.7a Using a feeler gauge to check a valve clearance

23.7b Adjusting a valve clearance

Allowance must be made for tightening the locknut, as this tends to decrease the valve clearance. Recheck the adjustment after tightening the locknut.

8 Repeat the procedure given in paragraphs 6 and 7 for the remaining valves. With the carburettor/inlet manifold fitted, some difficulty may be experienced when adjusting the exhaust valve clearances, and a suitable open-ended spanner bent to 90º will be found helpful.

9 Check the condition of the camshaft cover gasket, and renew if necessary. Fit the gasket to the camshaft cover ensuring that the locating tabs and dovetails are correctly located (see illustration),

23.9a Camshaft cover gasket dovetails

then refit the
camshaft cover and tighten the securing bolts in the order shown (see illustration),

23.9b Camshaft cover bolts (A) and spacer plates (B)

Tighten bolts in following stages: Stage 1 Bolts 1 to 6
Stage 2 Bolts 7 and 8
Stage 3 Bolts 9 and 10
Stage 4 Bolts 7 and 8 (again)

ensuring
that the spacer plates are in position under the bolt heads, where applicable.

10 On fuel injection models, refit the inlet manifold bracing strut.

11 Where applicable refit the spark plugs.

Reconnect the HT leads and locate them in the clips on the camshaft cover.

12 Where applicable, refit any wires and hoses to the clips on the camshaft cover and on carburettor models, refit the air cleaner.

DOHC and CVH engines
13 These engines are fitted with hydraulic cam followers therefore no adjustment is necessary.