1D-69 Engine Mechanical:
Main Bearings Inspection
S6JB0B1406046
Main Bearing General Information
NOTE
Before inspecting main bearings, note the
following points.
• Service main bearings are available in standard size
and 0.25 mm (0.0098 in.) undersize, and each of them
has 5 kinds of bearings differing in tolerance.
• Upper half of bearing (1) has oil groove (2) as shown
in figure. Install this half with oil groove toward
cylinder block.
• Lower half of bearing does not have oil groove.
Visual Inspection
Check bearings for pitting, scratches, wear or damage.
If any malcondition is found, replace both upper and
lower halves. Never replace either half without replacing
the other half.
Main Bearing Clearance
NOTE
Do not rotate crankshaft while gauging
plastic is installed.
Check clearance by using gauging plastic (1) according
to the following procedure.
1) Remove lower crankcase.
2) Clean bearings and main journals.
3) Place a piece of gauging plastic (1) to full width of
bearing (parallel to crankshaft) on journal, avoiding
oil hole.
4) Install lower crankcase to cylinder block without
applying sealant referring to “Main Bearings,
Crankshaft and Cylinder Block Removal and
Installation”.
5) Remove lower crankcase, and using scale (2) on
gauging plastic (1) envelop, measure gauging plastic
(1) width at its widest point. If clearance exceeds its
limit, replace bearing. Always replace both upper
and lower inserts as a unit.
A new standard bearing may produce proper
clearance. If not, it will be necessary to regrind
crankshaft journal for use of 0.25 mm undersize
bearing.
After selecting new bearing, recheck clearance.
Main Bearing Clearance for Standard Size
Bearing
Standard: 0.0210 – 0.0390 mm (0.0009 – 0.0015
in.)
Limit: 0.0520 mm (0.0020 in.)
Main Bearing Clearance for Undersize Bearing
Standard: 0.0240 – 0.0420 mm (0.0010 – 0.0016
in.)
Limit: 0.0550 mm (0.0021 in.)
IYSQ01143162-01
IYSQ01143163-01
IYSQ01143164-01