Suzuki Engine 2002 GRAND VITARA SQ420 Service Manual page 338

• Valve seat repair :
A valve seat not producing a uniform contact with its valve or
showing width of seating contact that is out of specified
range must be repaired by regrinding or by cutting and
regrinding and finished by lapping.
1) EXHAUST VALVE SEAT : Use valve seat cutters (1) to make
two cuts as illustrated in figure. Two cutters must be used :
the first for making 15° angle, and the second for making 45°
angle.
The second cut must be made to produce desired seat
width.
Seat width for exhaust valve seat
1.1 – 1.3 mm (0.0433 – 0.0511 in.)
2) INTAKE VALVE SEAT : Cutting sequence is the same as for
exhaust valve seats.
Seat width for intake valve seat
1.1 – 1.3 mm (0.0433 – 0.0511 in.)
3) VALVE LAPPING : Lap valve on seat (1) in two steps, first
with coarse size lapping compound applied to face and the
second with fine-size compound, each time using valve lap-
per according to usual lapping method.
Cylinder Head
• Remove all carbon from combustion chambers.
NOTE:
Do not use any sharp-edged tool to scrape off carbon. Be
careful not to scuff or nick metal surfaces when decar-
boning. The same applies to valves and valve seats, too.
• Check cylinder head for cracks in intake and exhaust ports,
combustion chambers, and head surface.
ENGINE MECHANICAL (G16 ENGINE) 6A1-47