Kohler RH255 Service Manual page 49

Assemble Cylinder Head
NOTE: Engine utilizes a valve stem seal on intake
valve. Always use a new seal when valves are
installed in cylinder head. Never reuse an old
seal.
1. Install valves into their respective positions.
2. Install a new valve seal on stem of intake valve.
3. Install valve springs and retainers into their
respective locations in cylinder head. Using hand
pressure, compress each valve spring and slide
each retainer onto valve stem to lock in place.
Install Cylinder Head
1. Check to make sure there are no nicks or burrs on
sealing surfaces of cylinder head or crankcase.
2. Rotate crankshaft to position piston at TDC on
compression stroke.
3. Install dowel pins into recesses around lower
cylinder head bolt holes and install a new cylinder
head gasket.
4. Install cylinder head and start screws. Tighten
screws initially to a torque of 12 N·m (106 in. lb.) in
several increments using sequence shown. Tighten
to a fi nal torque of 24 N·m (212 in. lb.).
Install Push Rods and Rocker Arms
NOTE: Push rods should always be installed in original
location.
1. Install push rod guide plate, aligning holes for rocker
arm studs. Install rocker arm studs and torque to
24 N·m (212 in. lb.).
2. Dip ends of push rods in engine oil and install them
in their respective locations, seating each into tappet
socket.
3. Assemble rocker arms, adjusters, and locknuts onto
rocker arm studs and push rods.
4. Adjust valve tappet clearance as follows:
a. Be sure piston is still at top of compression
stroke.
b. Insert a fl at feeler gauge between rocker arm and
valve stem. Recommended valve to rocker arm
clearance for intake is 0.1 mm (0.0040 in.) and
0.15 mm (0.0060 in.) for exhaust.
c. Adjust clearance as required by loosening locknut
and tightening adjuster.
Turn clockwise to decrease clearance.
Turn counterclockwise to increase clearance.
d. Hold adjuster from turning and tighten locknut.
Torque locknut to 10 N·m (88.5 in. lb.).
e. Recheck that clearance is correct.
5. Set gap of new spark plug to 0.76 mm (0.030 in.).
6. Install spark plug in cylinder head and torque to
27 N·m (20 ft. lb.).
18 690 06 Rev. --
Install Valve Cover
Sealant Pattern
A
NOTE: Always use fresh sealant. Using outdated
sealant can result in leakage. Refer to Tools and
Aids for information on sealant dispenser.
NOTE: To ensure proper adhesion of sealant to both
sealing surfaces, perform step 3 immediately (5
minutes maximum) after application of RTV.
RTV silicone sealant is used as a gasket between valve
cover and cylinder head. Refer to Tools and Aids for a
listing of approved sealants.
1. Prepare sealing surfaces of cylinder head and valve
cover.
2. Apply a 1.5 mm (1/16 in.) bead of sealant to valve
cover as shown.
3. Install valve cover on head with screws and torque to
8 N·m (70.8 in. lb.) using sequence shown.
Install Cylinder Shroud
Install cylinder shroud. Torque screws to 8 N·m
(70.8 in. lb.).
KohlerEngines.com
Reassembly
A
RTV Sealant
49