Valve Seat Inserts; Valve Guides - Isuzu Trooper II 1986 Manual

Remove valve cover. Starting with outer nuts and working
inward, loosen rocker arm shaft brackets. Disassemble rocker arm
shaft assembly by removing springs from shafts. Remove rocker arm
brackets and rocker arms. Keep parts in order for reassembly.
Inspection
1) Place rocker arm shaft on "V" blocks and check runout at
center of shaft. Maximum runout should not exceed .008" (.20 mm). A
slight amount of runout can be corrected with a press. DO NOT apply
heat. Replace shaft if runout is greater than .016" (.41 mm).
2) Measure rocker arm shaft diameter at 4 rocker arm
locations. Replace shaft if diameter is less than .801" (20.35 mm).
Measure inside diameter of rocker arms. If clearance is greater than
.008" (.20 mm), replace either rocker arms or shaft. Replace rocker
arms if valve stem contact area is scored or worn.
Installation
1) Reassemble rocker arm shaft components in original
positions. Cylinder number on upper face of brackets must point
toward front of engine. Longer rocker shaft must be installed on
exhaust side. Punch marks on rocker arm shafts must face front and
point up.
2) Coat rocker arm shaft, rocker arms, and valve stems with
engine oil. Install rocker arm shaft assembly on cylinder head. Align
camshaft mark with mark on No. 1 rocker arm shaft bracket. On turbo
models, apply silicon gasket material to No. 1 rocker arm bracket
mounting surface on cylinder head.
3) Starting with inner nuts and working outward, tighten
brackets in steps. Adjust valve clearance and install valve cover.

VALVE SEAT INSERTS

Inspection
With valves installed in cylinder head, check depth of valve
head below cylinder head surface. If depth is more than .067" (1.70
mm), replace valve seat insert.
Removal
Weld a bead at several points on inner face of valve seat
insert, away from aluminum alloy parts. Allow cylinder head to cool
for 2-5 minutes. Loosen valve seat insert by striking beads. Pull out
inserts.
Installation
Clean valve seat insert recess. Heat cylinder head with
steam to expand insert area. Chill valve seat with dry ice and press
insert into head. Interference fit is .0031-.0047" (.079-.119 mm).

VALVE GUIDES

Inspection
Measure valve guide and corresponding valve for wear. If
stem-to-guide clearance is greater than .008" (.20 mm) on intake
valves or .0097" (.246 mm) on exhaust valves, replace valve guides
and valves as necessary.
Removal
Working from combustion chamber side of head, use Valve
Guide Driver (J-26512-1) to drive guide out of head. Remove lower
spring seat.
Installation
Lubricate outside of new guide with engine oil. Working from