4. DISASSEMBLY, INSPECTION AND REASSEMBLY OF ENGINES 4.2.5 Parts inspection and measurement (1) Cylinder head Clean the cylinder head, mainly the combustion surface, valve seats and intake/exhaust ports, remove carbon deposit and bonding agent, and check the surface state. (a) Appearance check Check mainly discoloration and crack. If crack is suspected, perform color check. (b) Combustion surface distortion Apply a straight-edge in two diagonal direc- tions and on four sides of the cylinder head, and measure distortion with a thickness gauge. mm (c) Valve sink Measure with the valve inserted to the cylin- der head. mm (d) Seat contact Apply a thin coat of minimum on the valve seat.
Insert the valve in the cylinder and push it against the seat to check seat con- tact. Standard: Continuous contact all around 82E-5 – 98E-5 SERIES 4-19 Standard Limit Distortion 0.05 or less 0.15 Standard Limit 3D82AE (2-valve head) Intake 0.35 – 0.55 0.8 Exhaust 0.30 – 0.50 0.8 4D84E (S)3D84E 3D88E 4D88E (2-valve head) Intake 0.30 – 0.50 0.8 Exhaust 0.30 – 0.50 0.8 S4D84E 4D94LE (S)4D98E (4-valve head) Intake 0.36 – 0.56 0.8 Exhaust 0.35 – 0.55 0.8