Perkins 103-06, Workshop Manual

Page: 19 / 80

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
0.025-0.052mm
(.001-.002")
Exhaust valve
150"
Standard clearance Allowable limit
more than 0.2mm (
.008")
Contacting
width
Standard clearance
Allowable limit
0.045-0.072mm
(.0018-.0028")
more than 0.25mm
(.010")
1068
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
0.85-1.15mm (
.034-.045")
Depth
Standard recess Allowable limit
1 8mm
( 071 ')
Clearance
1067
1069
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
103 06
Standard recess Allowable limit
0.70-0.90mm (.
0276-.0354")
1.8mm
(.071')
Standard width
Allowable limit
1.7-2.1 mm (.
067-.082")
2.5mm
(098 )
103-06
Standard width
Allowable limit
1.59-1.80mm (.
0626-.0709")
2 5mm
(098)
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.