695578
Chapter 9
Cylinders and Cylinder Heads
Cylinder Service
Check cylinder for dirty, broken or cracked fins, worn or
scored bearings or scored cylinder bore surface, and
warped head mounting surface.
If cylinder bore is out-of round, scored or worn more
than .005'’ (.13 mm) oversize, it should be replaced or
rebored to .010 (.254 mm) or .020 (.50 mm) oversize. In
some cases engines are built with an oversize cylinder;
in these instances they are identified with the oversize
value imprinted on the cylinder as pictured. Service
pistons have the oversized valve marked on the dome.
Do not use valves with
undersized margins. Doing so
may result in a valve that does not seat normally,
burns easily, and can also lead to valve cracking.
Reboring
NOTE
To rebore cylinder we recommend using a reputable ma-
chine shop or service center.
After reboring, hone the cylinder with 380 grit stone to
obtain a good cross hatch pattern for proper ring
seating.
Clean cylinder with soap and water, and dry thoroughly.
Replace piston and piston rings with correct oversize
parts as indicated in parts manual.
Cylinder Heads
Check cylinder heads for warpage by placing on a flat
surface. If the cylinder head gasket surface is warped in
excess of .005 inches (.13 mm), replace the head.
The numerical order for gradually
removing and tightening head
screws on the cylinder head is critical for proper
distribution of pressure over gasket area. It
prevents stud failure, gasket leaks including head
and cylinder distortion.
Always replace head gasket and torque head bolts in 50
inch lb. (5.6 Nm) increments in the numbered sequence
to a torque of 180-220 inch lbs. (20.3 - 25 Nm).
Only a thin oil film is allowed to
remain on cylinder head screws.
Excess oil will pool in the head screw sleeve,
preventing proper torque application and full
thread engagement.
Torque in Numerical Order
1
5
2
7
4
3
6
Indicates .010 (.254 mm) Oversize Piston
.010
(.254 mm)
9-1
CAUTION
CAUTION
CAUTION
