Connecting Rod And Piston - Westerbeke WPDS-20 Technical Manual

A26
CONNECTING ROD AND PISTON
1. Separate the piston from the connecti ng rod.
2. Check the gudgeon pin clearance in the little-end
bush against the figure in Data. If the clearance is
excessive, renew the little-end bush.
a.
Position the new bush with its jOi nt on the cap
side of the connecting rod as shown in Fig. 1.
b. Finish-ream the bush to the size given in Data.
3. Check the piston ring groove clearance and the
piston ring gap against the figures in Data. Renew
the rings, or piston and rings, as necessary.
4. Assemble the piston to the connecting rod with
the combustion cavity and oil jet hole in line as
shown in Fig. 2.
Data
Gudgeon pins
Diameter
Fit in piston
Fit in connecting rod
Little-end bushes
Inside diameter (reamed in position)
Pistons and rings
Ring/groove clearance:
Top and 2nd (compression)
3rd (stepped scraper)
4th (slotted scraper)
Ring gap: Top
Remainder
1--'----
Fig. 1
Fig. 2
1·1248 to 1·1250 in. (28·57 to 28·58 mm.)
·0003 in. (-008 mm.) clearance to ·0001 in. (-003 mm.)
interference
·0005 to ·0012 in. (·013 to ·030 mm.) clearance
1-1255 to 1·1260 in. (28-588 to 28·60 mm.)
·0026 to ·0046 in. (-066 to ·117 mm.)
·0026 to ·0046 in. (-066 to ·117 mm.)
·0025 to ·0045 in. (-064 to ·114 mm.)
·014 to ·019 in. (·36 to ·48 mm.)
·010 to ·015 in. (·25 to ·38 mm.)