Set Valve Clearances
Setting valve tappet (Cam followers) clearances on the Perkins 152 motor.
Tools required :
1/2 open ended spanner
9/16 open ended spanners * 2
Turn the crankshaft pulley in the normal direction of rotation until the followers 1 & 3 protrude to their maximum height from the cylinder head face. Adjust clearances on followers 2, 4, 5, & 6 to a gap of 012″ (0.30mm) when engine is cold. (If warm 010″ / 0.254mm)
Make a mark on the crankshaft pulley and timing cover. Turn the crankshaft one complete revolution until the marks line up again (Turn clockwise if looking from front of engine). Set clearances on followers 1 & 3
Before setting clearances the following should be observed. Your motor has been running for many years. The face of the rocker becomes worn (Indented) from repeatedly opening a valve. Carefully machine the surface to it’s original profile.
Check the condition of the setting bolt thread (3/8″ UNF) & replace if worn – stretched. If you use a standard high tensile bolt be sure to machine bolt head markings until flat.
After fastening lock nut ensure clearance is correct as the gap tends to get smaller. Run engine until warm and recheck settings. If the rocker shaft is removed replace using a hardened flat washer under fastening nuts (3/8″ UNF).
Torque to 60NM.
Refit the rocker cover. Using a good quality contact adhesive, glue the new gasket to the cover. Use a good quality gasket sealant between the gasket and cyl head face. Use sealant conservatively. Exess sealant causes havoc with the engines oil feed system. Inspect the cover fit and knock high spots down for a uniform fit.
Ensure that both the rocker cover breather outlet & breather pipe are clean & free of obstruction to avoid what appears to be exessive blow-by through the engines dipstick.
After installing rocker cover seal the two nuts with a gasket sealant to prevent oil leakage