Page 69 - Mechanic Diesel - TT

MECHANIC DIESEL - CITS

• Place head on head stands and put it on a shelf in solvent tank
• Install valves in the ports
• Fill the combustion chambers with solvent and check for leaks
Reassembling the Head and Valve Guide Seal Installation

• Clean head before reassembly
• Thoroughly clean the guides
• Lubricate all valve stems
• Valve guide seal installation
• Install guide seals before installing springs on all but O-ring seals

• Check instructions in gasket set regarding placement of seals
• Lubricate seals before installing them
• Positive seals: often supplied with a plastic sheath
Install the Valve and Spring Assembly
• Some springs have coils more closely spaced at one end than at the other

• End more tightly coiled IS positioned against the cylinder head
• Compress spring just enough to install keepers
• Inspect each keeper for wear
• Use grease to help hold keepers in place

• Newer engines may use been hive-shaped springs
• One end of coils smaller in diameter
Pushrod Engine Rocker Arm Service
• Stud-mounted rocker arms
• Not serviceable
• Replaced when worn

• Cast rocker arms that are shaft-mounted
• Can be reground
• Thoroughly lubricate rocker arms
• Before installing

Inspect Pushrods and OHC Camshaft
Inspect pushrod ends and surface of socket where it pivots on rocker arm
• Look for pitting or other unusual wear
• Roll pushrods on a bench to see if they are bent
• Overhead camshafts often have oil galleries and holes drilled in cam lobes for direct lubrication

• Small oil holes are prone to plugging
• Check that oil holes are clear before installing
Reassembling OHC Head
• Important steps

• Reinstall camshaft in the head
• Check to see camshaft cap alignment bushings are installed and positioned correctly

56
CITS : Automotive - Mechanic Diesel - Lesson 11 - 14