6A1-72 ENGINE MECHANICAL (G13B, 1-CAM 16-VALVES ENGINE)
5) Remove cap and using scale (2) on gaging plastic (1) envelope,
measure gaging plastic width at its widest point. If clearance ex-
ceeds 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.
StandardLimit
Bearing clearance0.020 – 0.040 mm
(0.0008 – 0.0016 in.)0.060 mm
(0.0023 in.)
Selection of main bearings
STANDARD BEARING:
If bearing is in malcondition, or bearing clearance is out of specifica-
tion, select a new standard bearing according to the following pro-
cedure and install it.
1) First check journal diameter by using the following procedure.
As shown in figure, crank webs (1) of No.2 and No.3 cylinders
have five stamped numerals.
Three kinds of numerals (“1”, “2” and “3”) represent the following
journal diameters.
Numeral stamped
Journal diameter
144.994 – 45.000 mm
(1.7714 – 1.7716 in.)
244.988 – 44.994 mm
(1.7712 – 1.7714 in.)
344.982 – 44.988 mm
(1.7709 – 1.7712 in.)
The first, second, third, fourth and fifth (left to right) stamped nu-
merals represent journal diameters at bearing caps “1”, “2”, “3”,
“4” and “5” respectively.
For example, in figure, the first (leftmost) numeral “3” indicates
that journal dia. at bearing cap “1” is within 44.982 – 44.988 mm,
and second one “1” indicate that journal dia. at cap “2” is within
44.994 – 45.000 mm.
ENGINE MECHANICAL (G13B, 1-CAM 16-VALVES ENGINE) 6A1-77
5) Rebore and hone cylinder to calculated dimension.
NOTE:
Before reboring, install all main bearing caps in place and
tighten to specification to avoid distortion of bearing bores.
6) Measure piston clearance after honing.
INSTALLATION
NOTE:
All parts to be installed must be perfectly clean.
Be sure to oil crankshaft journals, journal bearings, thrust
bearings, crankpins, connecting rod bearings, pistons, pis-
ton rings and cylinder bores.
Journal bearings, bearing caps, connecting rods, rod bear-
ings, rod bearing caps, pistons and piston rings are in com-
bination sets. Do not disturb such combination and make
sure that each part goes back to where it came from, when
installing.
1) Install main bearings to cylinder block.
One of two halves of main bearing (2), has an oil groove (3).
Install it to cylinder block (1), and the other half without oil groove
to bearing cap.
Make sure that two halves are painted in the same color.
2) Install thrust bearings (1) to cylinder block between No.2 and
No.3 cylinders. Face oil groove (2) sides to crank webs.
