Perkins 103-06 Workshop Manual page 19

d. Valve to valve-guide clearance
Check the clearance between the valve and
valve guide. If the clearance exceeds the
allowable limit, replace.
Intake valve
Standard clearance
0.025-0.052mm
(.001-.002")
Exhaust valve
Standard clearance
0.045-0.072mm
(.0018-.0028")
C. Valve seat
a. Valve seat contact width
If the contact width of the valve seat is more
than allowable width, check wear condition
of the valve guide first.
Using the seat cutters of 15° 45° and 75°
correct the seat.
103-09/10/Perama M25/M30
Standard width
1.7-2.1 mm (.
067-.082")
103-06
Standard width
1.59-1.80mm (.
0626-.0709")
Allowable limit
more than 0.2mm (
.008")
Allowable limit
more than 0.25mm
(.010")
Clearance
1067
Allowable limit
2.5mm
(098 )
Allowable limit
2 5mm
( 0 9 8 )
150"
b. Recess of valve seat
If the recess is more than allowable limit,
replace the valve seat (if fitted).
103-09/10/Perama M25/M30
Standard recess
1 8mm
0.85-1.15mm (
( 071 ')
.034-.045")
Depth
103 06
Allowable limit
Standard recess
0.70-0.90mm (.
1.8mm
0276-.0354")
(.071')
Replacement of valve seat insert (where
fitted):
Either 1. Using gas burner (700 to 800°C),
heat diagonally across the valve seat insert.
Leave in air for 3 to 5 minutes and remove
the valve seat insert by light tapping (
ensuring the head is not damaged).
Or 2. Machine the insert out taking care not
to damage the head.
Clean up the insert bore and fit new insert
using a press (1,000 to 1,500kgf) and a suit-
able smooth surface tool. To assist process,
chill the valve seat insert with liquid nitrogen
etc or heat the head to between 60 and
100°C.
Contacting
width
1068
Allowable limit
1069