PISTONS, PINS AND RINGS
Cleaning The Pistons, Pins And Rings
Remove debris from the piston surfaces. Clean debris from the piston skirt, piston pins and rings with solvent.
Clean the ring grooves with a ring groove cleaner. Make sure the oil ring slots are clean.
Checking The Pistons, Pins And Rings
Replace the pistons that show signs of over maximum wear
or
damage.
Check the piston to cylinder bore clearance by measuring the piston and bore diameters. Refer to
Page
7B-19
Cylinder
Block for the bore measurement procedure. Measure the outside diameter of the piston with micrometers about
2-14
inches (57,15 mm) below the dome and at 90° to the piston pin bore. Check the ring side clearance. (See Page
78-14
Installing Piston Rings.)
Check the outside diameter of the piston pin and the inside diameter of the pin bore in the piston. Make replacement of
any piston pin
or
piston that is not
in
specifications.
Replace
all rings that have damage. Check the end gap and the side clearance. Rings must not be moved from one piston
and installed on another.
MAIN BEARINGS AND CONNECTING ROD BEARINGS
NOTE:
Main bearings have
color
codes
to
identify
size. See SPECIFICATIONS Section
8B-1.
Cleaning Bearings
Clean the bearing inserts and caps in solvent and dry them with compressed air. Do not remove deposits from the bearing
shells.
Checking Bearings
Check each bearing carefully. Bearings that have damage
or
excessive
wear
need replacement. Check the clearance of
bearings that
look good with Plastigage. (See Page
7B-15
To
Check
Or
Connection Rod Bearings With P/astigage.)
CYLINDER BLOCK
Cleaning The Cylinder
Block
After any cylinder bore repair operation clean the bore with soap and water. The rinse the bore with clean water to remove
the soap and wipe the bore with a clean cloth with engine
oil on
it.
If
the engine is disassembled clean the block with solvent. Remove old gasket material from all machined surfaces. Remove
all pipe plugs that seal oil passages and clean all the passages. Clean all passages, bolt holes, etc., with compressed air.
Make sure the threads in the
cylinder head bolt holes are clean.
Use a tap to clean the threads and to remove any debris.
Clean the groove in the crankshaft bearing and bearing retainers.
Revised Oct. 97
-7B-20-
741,742,743,
743DS Bobcat Loader
Service Manual
To Next Page
Loading...