Figure; Components; Disassembly Of Crankshaft And Piston - Yanmar 4TNV98 Service Manual

Disassembly of Crankshaft and Piston

Components

Removal of Pistons
CAUTION
Keep the piston pin parts, piston assemblies,
and connecting rod assemblies together to be
returned to the same position during the
reassembly process. Label the parts using an
appropriate method.
IMPORTANT
Engines with high operating hours may have a ridge
near the top of the cylinders that will catch the piston
rings and make it impossible to remove the pistons.
Use a suitable ridge reamer to remove ridges and
carbon prior to removing the pistons.
NOTE : Pistons can fall from cylinder block if the
engine is inverted. Rotate the engine so the
connecting rods are horizontal before removing the
connecting rod caps.
4TNV98 & 4TNE98 Diesel Engine
1. Using a feeler gauge, measure the connecting rod
side clearance as shown (Figure 6-97). See
Connecting Rod on page 72 for the standard limit.
If the measurement is out of specification, replace
the crankshaft, connecting rod, or both.
2. Measure bearing oil clearance prior to removing
the pistons and connecting rods to determine
extent of wear. Record the measurements.
116

Figure 6-97

Section 3. Engine