Kohler MAGNUM M18

SECTION 10
INSPECTION AND RECONDITIONING
POSI-LOCK CONNECTING RODS
Posi-Lock Connecting Rods are used in all Magnum
M18 and M20 engines. Because of the increase in
piston pin boss thickness of the new, style D pistons
used, the connecting rods on these engines have a
narrower piston pin end than on older style Posi-Lock
connecting rods. Therefore, the Posi-Lock connecting
rods for the new pistons are not interchangeable with
ihe Posi-Lock connecting rods for the standard pis-
tons used on KT17 and КТ19, and KT17* and KT19
Series I| engines. Refer to Figure 10-16.
K" Engines
Connecting Rod.
-— 800
Magnum Engines
Connecting Rod
Figure 10-16. Posl-Lock Connecting Rods.
*NOTE: KT17 Series II engines built after Serial
No. 15089862 are equipped with the new style
D pistons, piston rings, and connecting rods.
Inspection and Service
Check bearing area (big end) for excessive wear,
Score marks, running and side clearances (Refer to
Section 1, "Specifications, Tolerances, and Special
Torque Values"). Replace rod and cap if scored or
excessively wom.
Service replacement connecting rods are available in
STD crankpin size and .010" undersize. The .010"
undersized rod can be identified by the drilled hole
located in the lower end of the rod shank (refer to
Figure 10-17). Always refer to the appropriate parts
information to ensure that correct replacements are
used.
Standard
:010" Undersize :
Figure 10-17. Standard and .010" Undersize Service
Connecting Rods.
CAMSHAFT AND CRANKSHAFT
Inspection and Service
Inspect the gear teeth on both the crankshaft and
camshaft. If the teeth are badly wom, chipped, or
some are missing, replacement of the damaged com-
ponents will be necessary.
Also, inspect the crankshaft bearings for scoring,
grooving, etc. Do not replace bearings unless they
show signs of damage or are out of running clearance
specifications. If crankshaft tums easily and noise-
lessly, and there is no evidence of scoring, grooving,
etc., on the races or bearing surfaces, the bearings
can be reused.
Check crankshaft keyways. If worn or chipped, re-
placement of the crankshaft will be necessary. Also
inspect the crankpin for score marks or metallic pick-
up. Slight score marks can be cleaned with crocus
cloth soaked in oil. If wear limits, as stated in
“Specifications and Tolerances” are exceeded, it will
be necessary to either replace the crankshaft or re-
grind the crankpin to .010" undersize. If reground, a
010" undersize connecting rod (big end) must then be
used to achieve proper running clearance. Measure
the crankpin for size, taper, and out-of-round.
NOTE: If the crankpin is reground, visually check to
insure that the fillet blends smoothly with the
crankpin surface. Refer to Figure 10-18.
10.13