Mack E7 Service Manual page 126

5-101.bk Page 36 Friday, March 17, 2006 11:05 AM
VALVE SEAT INSERT COUNTERBORE
Refer to Figure 5-45.
Valve seat at counterbore depth (3):
— Exhaust: 0.376–0.372 inch
(9.55–9.449 mm)
— Inlet: 0.364–0.360 inch
(9.246–9.144 mm)
Inlet valve seat insert counterbore
diameter (4): 1.8295–1.8285 inches
(46.4693–46.4439 mm)
Exhaust valve seat counterbore diameter
(5): 1.6885–1.6875 inches
(42.8879–42.8625 mm)
1
5
Figure 5-45 — Valve Seat Insert Counterbore
Dimensions
1. Exhaust valve guide
2. Inlet valve guide
3. Valve seat at
counterbore depth
INSPECTION
Refer to Figure 5-46.
1. With valve seat insert removed from cylinder
head (2), clean surfaces thoroughly with
wire brush.
Page 5-36
200 BENCH PROCEDURES
2
4
3
200302a
4. Inlet valve seat insert
counterbore diameter
5. Exhaust valve seat
counterbore diameter
2. Check surface finish for smoothness. Check
counterbore diameter with an inside
diameter micrometer (1). Refer back to
specifications listed in Figure 5-45.
Figure 5-46 — Checking Counterbore Dimensions
1. Inside diameter 2. Cylinder head
micrometer
VALVE SEAT INSERT INSTALLATION
Oversize inlet and exhaust valve seat inserts are
available in 0.005, 0.015, 0.031, 0.047 and
0.062 inch sizes if counterbore requires
machining.
1. If required, machine the inlet and exhaust
valve seat insert counterbores using tool
HT77136.
Refer to Figure 5-47.
2. Position valve seat insert (1) over
corresponding counterbore. Install inserts
using valve seat insert installation set
J 38586 (2). Use driver handle J 8092 (3) to
drive valve seat insert into counterbore.