Crankshaft; Inspection - Volvo Penta TAD1630G Workshop Manual

Group 21
19
Check the axial play of the crankshaft. Max play 0.19 mm
(0.0075").
20
Fit the flywheel and the flywheel casing.
Torque:
Flywheel casing 140 Nm (103.3 ft-lb)
Fywheel 260 Nm (191.7 ft-lb)
21
Fit the polygon hub and the vibration damper.
Torque:
Center bolt, crankshaft 640 Nm (472.0 ft-lb).
22
Fit the oil pump, the oil strainer and the oil delivery pipe.
Note: Before refitting the oil pump, check the delivery pipe at
the pipe coupling against the block to make sure it has not
been nipped. Push the delivery pipe in until it bottoms in the
block. Torque the union until it stops (<10 Nm/7.4 ft-lb). Now
mark the union with a felt tipped pen and tighten it a further
60° into the block.
23
Fit the timing cover.
24
Fit the pan. Torque the bolts in a specified order. See
"Workshop manual, Technical Data".
25
Fit the pulley and the outer torsional vibration damper (if
any). Torque 48 Nm (35.4 ft-lb).

Crankshaft

The crankshaft is nitro-carburized.
A nitro-carburized crankshaft has a greater resistance to fa-
tigue and wear than an induction-hardened crankshaft.

Inspection

The inspection of the crankshaft must be extremely thorough
to avoid unnecessary reconditioning. To determine recondi-
tioning requirements, the following applies:
A. Measure the bearing journals for out-of roundness, wear
and taper. See "Workshop manual, Technical Data".
B. Assess the surface damage.
For nitro-carburized shafts, the following applies:
What on an induction-hardened crankshaft may be re-
garded as scoring due to dirt can in the case of a nitro-
carburized shaft be the normal surface finish as on a
new crankshaft. The markings show up very clearly on
a shaft that has been in use because of the shiny bear-
ing surfaces. Very small particles can loosen from the
thin surface layer after the shaft has been in use for
some time.
This phenomenon is easily confused with scoring
caused by dirt, but close inspection will show that the
marks do not go entirely round the bearing journal and
have uneven edges. These slight defects do not neces-
sarily require regrinding of the crankshaft.
As a rule, it is sufficient to polish the bearing journal and
fit a new bearing shell.
C. Measure crankshaft alignment (throw).
The crankshaft should be placed on either a pair of V-
blocks, under 1st and 7th main bearing journals, or fixed
between stocks. Measurements should be made on the
4th main bearing.
The following applies with regard to the values measured:
1
Less than 0.2 mm (0.0079") - no alignment necessary if
wear and surface damage do not necessitate regrinding.
2
Align with care between 0.2-0.7 mm (0.0079-0.0276") to
avoid over-alignment.
Note: Do not align more than absolutely necessary.
3
More than 0.7 mm (0.0276") - the shaft must be scrapped
due to risk of cracking during alignment.
Service procedures - engine
69