New Holland 40 Series Repair Manual page 42

- - - - - - - - - - PART 1 - ENGINE S Y S T E M S - - - - - - - - - -
9. Hone the cylinder bore to:-
Grade A, 4.4007-4.4015 in.
Grade B, 4.4015-4.4023 in.
NOTE: Surface finish to be an average of 20
to 30 Microns, cross hatched at 35°-55°.
Maximum Taper:
0.001 in (0.025mm) through to bottom of the
bore.
Maximum Ovality:
0.0015 in (0.038mm)
Re-Assembly
NOTE: Pistons that are replaced must be of
the same type that were removed and have
the same identification letters and numbers
as embossed on the underside of the old pis-
ton.
,
.
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Piston to Cylinder Block Height
1. Dial Indicator
1. Upon re-assembly with the piston at Top
Dead Centre, ensure the piston to block
height is correct using a dial indicator,
Figure 41.
Naturally Aspirated:
0.011-0.023 in (0.28-0.58mm)
Turbocharged:
00.00-0.012 in (0-0.3mm)
24
2. Check the piston to bore clearance in the
following manner.
A, Measure the cylinder bore diameter cross-
wise, then measure piston diameter at right
angles to the piston pin.
B, Subtract piston diameter from the bore di-
ameter and the resultant figures should be:-
0.0065-0.0055 in (0.165-0.140mm)
Naturally Aspirated,
0.0065-0.0075 in (0.165-0.190mm
Turbocharged engines.
NOTE: Pistons are available as standard and
oversize, new pistons should always be fitted
if the clearance exceeds specification.
C, If clearance is "greater" try a similar new
piston, if limit is still exceeded measure re-
maining cylinder bores and pistons and es-
tablish greatest clearance.
Based on the highest figure, re-bore to take
the next oversize piston.
D, If the clearance is "less" hone bore to ob-
tain desired clearance.
42
Piston Connecting-Rod Alignment
1 . Piston 2. Pip on Rod
3. Lubricate all of the components with en-
gine oil and assemble the connecting rod
and piston, with the letter or grade mark
on the piston, aligned to the pip on the
connecting rod. Install the piston pin and
retainers, Figure 42.