Crankshaft Bearing Selection - Isuzu 4JA1 Workshop Manual

6. Remove the bearing cap.
7. Compare the width of the Plastigage attached to either the
crankshaft or the bearing against the scale printed on the
Plastigage container.
If the measured value exceeds the specified limit, perform
the following additional steps.
1. Use a micrometer to measure the crankpin outside
2. Use an inside dial indicator to measure the bearing
Crankpin and Bearing Clearance
4JA1T (L),
4JA1TC
4JH1TC

CRANKSHAFT BEARING SELECTION

Crankshaft bearing selection is based on the measured
diameters of the crankshaft journals and the bearing inserts.
Match the crankshaft bearing housing grade marks and the
crankshaft journal grade marks in the table below to determine
the correct crankshaft bearing size.
Crankshaft Bearing Housing Grade Mark
Position
Crankshaft bearing housing grade marks 1, 2 or 3 are stamped
on the rear right hand side of the cylinder body.
015LX060
Crankshaft Journal Grade Mark Position
The crankshaft journal grade marks (1 or -, 2 or --, 3 or ---) are
stamped on each crankshaft journal web.
The crankshaft journal and bearing clearance must be the
same for each position after installation of the crankshaft and
the crankshaft bearings.
NOTE:
The crankshaft journal mark No. 4 is stamped on
RTW86ASH002401
crankshaft No. 4 journal web front side or rear side.
ENGINE MECHANICAL 6A – 83
diameter.
inside diameter.
If the crank pin and bearing clearance exceeds the
specified limit, the crankshaft and/or the bearing must
be replaced.
Standard
0.029-0.066
(0.0011-0.0026)
0.029-0.083
(0.0011-0.0033)
mm (in)
Limit
0.100 (0.0039)
0.100 (0.0039)