Main Bearings Inspection - Suzuki Jimny Workshop Manual
1D
Main Bearings Inspection
General Information
•
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 an oil groove (2) as shown in the figure.
Install this half with oil groove to cylinder block.
• Lower half of bearing does not have an oil groove.
• Upper half of bearing (1) has an oil groove (2) as shown in the figure.
Install this half with oil groove to cylinder block.
• Lower half of bearing does not have an oil groove.
Visual Inspection
Check bearings for pitting, scratches, wear or damage.
If any malcondition is found, replace both upper and lower halves. Do not replace either half without replacing the other half.
Main Bearing Clearance
CAUTION:
Do not rotate crankshaft while gauging plastic is installed.
Check clearance by using gauging plastic according to the following procedure.
1)
Remove bearing caps.
2)
Clean bearings and main journals.
3)
Place a piece of gauging plastic (1) the full width of bearing (parallel to crankshaft) on journal, avoiding oil hole.
4)
Tighten main bearing cap No.1 bolts (1) – (10) and main bearing cap No.2 bolts (11) – (20) gradually as follows.
a)
Tighten bolts (1) – (10) to 30 N·m (3.0 kgf-m, 22.0 lbf-ft) according to numerical order in the figure.
b)
In the same manner as in Step a), tighten them to 50 N·m (5.0 kgf-m, 36.5 lbf-ft).
c)
In the same manner as in Step a), retighten them to 60°.
5)
Remove bearing caps and using scale (1) on gauging plastic envelop (2), measure gauging plastic 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 (0.0098 in) undersize bearing.
After selecting new bearing, recheck clearance.
A new standard bearing may produce proper clearance. If not, it will be necessary to regrind crankshaft journal for use of 0.25 mm (0.0098 in) undersize bearing.
After selecting new bearing, recheck clearance.
Main bearing clearance
Standard: 0.025 – 0.045 mm (0.0010 – 0.0018 in.)
Limit: 0.065 mm (0.0026 in.)
NOTE:
After checking the bearing clearance, check for thread deformation of each bearing cap No.1 bolt according to previous mentioned Step 4) once again.
Selection of Main Bearings
Standard bearing
If bearing is in malcondition, or bearing clearance is out of specification, select a new standard bearing according to the following procedure and install it.
1)
First check journal diameter. As shown in the figure, crank web No.2 has stamped numbers.
Three kinds of numbers (“1”, “2” and “3”) represent the following journal diameters.
Stamped numbers on crank web No.2 represent journal diameters marked with an arrow in the figure respectively. For example, stamped number “1” indicates that corresponding journal diameter is 44.9940 – 45.0000 mm (1.7714 – 1.7717 in.).
Three kinds of numbers (“1”, “2” and “3”) represent the following journal diameters.
Stamped numbers on crank web No.2 represent journal diameters marked with an arrow in the figure respectively. For example, stamped number “1” indicates that corresponding journal diameter is 44.9940 – 45.0000 mm (1.7714 – 1.7717 in.).
Crankshaft journal diameter
| Stamped numbers | Journal diameter |
|---|---|
| 1 | 44.9940 – 45.0000 mm (1.7714 – 1.7717 in.) |
| 2 | 44.9880 – 44.9940 mm (1.7712 – 1.7714 in.) |
| 3 | 44.9820 – 44.9880 mm (1.7709 – 1.7712 in.) |
2)
Next, check bearing cap bore diameter without bearing. On mating surface of cylinder block, five alphabets are stamped as shown in the figure.
Three kinds of alphabets (“A”, “B” and “C”) represent the following cap bore diameters.
Stamped alphabets on cylinder block represent bearing cap bore diameter marked with an arrow in the figure respectively.
For example, stamped “A” indicates that corresponding bearing cap bore diameter is 49.0000 – 49.0060 mm (1.9291 – 1.9294 in.).
Three kinds of alphabets (“A”, “B” and “C”) represent the following cap bore diameters.
Stamped alphabets on cylinder block represent bearing cap bore diameter marked with an arrow in the figure respectively.
For example, stamped “A” indicates that corresponding bearing cap bore diameter is 49.0000 – 49.0060 mm (1.9291 – 1.9294 in.).
Crankshaft bearing cap bore
| Stamped alphabet | Bearing cap bore diameter (without bearing) |
|---|---|
| A | 49.0000 – 49.0060 mm (1.9291 – 1.9294 in.) |
| B | 49.0060 – 49.0120 mm (1.9294 – 1.9296 in.) |
| C | 49.0120 – 49.0180 mm (1.9296 – 1.9298 in.) |
3)
There are 5 kinds of standard bearings differing in thickness. To distinguish them, they are painted in the following colors at the center of bearings.
Each color indicates the following thickness.
Each color indicates the following thickness.
Standard size of crankshaft main bearing thickness
| Color painted | Bearing thickness |
|---|---|
| Pink | 1.990 – 1.994 mm (0.0783 – 0.0785 in.) |
| Purple | 1.993 – 1.997 mm (0.0785 – 0.0786 in.) |
| Brown | 1.996 – 2.000 mm (0.0786 – 0.0787 in.) |
| Green | 1.999 – 2.003 mm (0.0787 – 0.0789 in.) |
| Black | 2.002 – 2.006 mm (0.0788 – 0.0790 in.) |
| 1. | Paint |
4)
From number stamped on crank web No.2 and alphabets stamped on cylinder block, determine new standard bearing to be installed to journal, by referring to the table shown below.
For example, if number stamped on crank web No.2 is “1” and alphabet stamped on cylinder block is “B”, install a new standard bearing painted in “Purple” to its journal.
For example, if number stamped on crank web No.2 is “1” and alphabet stamped on cylinder block is “B”, install a new standard bearing painted in “Purple” to its journal.
New standard size crankshaft main bearing specification
| Number stamped on crank web No.2 (Journal diameter) | ||||
|---|---|---|---|---|
| 1 | 2 | 3 | ||
|
Alphabet stamped on cylinder block
(Cap bore dia.) |
A | Pink | Purple | Brown |
| B | Purple | Brown | Green | |
| C | Brown | Green | Black | |
| New standard bearing to be installed | ||||
5)
Using scale (1) on gauging plastic (2), check bearing clearance with newly selected standard bearing.
If clearance still exceeds its limit, use next thicker bearing and recheck clearance.
If clearance still exceeds its limit, use next thicker bearing and recheck clearance.
6)
When replacing crankshaft or cylinder block due to any reason, select new standard bearings to be installed by referring to number stamped on new crankshaft or alphabets stamped on new cylinder block.
Undersize bearing (0.25 mm (0.0098 in.))
•
0.25 mm (0.0098 in.) undersize bearing is available, in five kinds varying in thickness.
To distinguish them, each bearing is painted in the following colors at center of bearing.
Each color represents the following thickness.
•
If necessary, regrind crankshaft journal and select undersize bearing to use with it as follows.
To distinguish them, each bearing is painted in the following colors at center of bearing.
Each color represents the following thickness.
Undersize of crankshaft main bearing thickness
| Color painted | Bearing thickness |
|---|---|
| Red and Pink |
2.115 – 2.119 mm
(0.0830 – 0.08340 in.) |
| Red and Purple |
2.118 – 2.122 mm
(0.08340 – 0.08350 in.) |
| Red and Brown |
2.121 – 2.125 mm
(0.08350 – 0.08370 in.) |
| Red and Green |
2.124 – 2.128 mm
(0.08360 – 0.08380 in.) |
| Red and Black |
2.127 – 2.131 mm
(0.08376 – 0.08390 in.) |
| 1. | Paint |
a.
Regrind journal to the following finished diameter.
b.
Using micrometer, measure reground journal diameter.
Measurement should be taken in two directions perpendicular to each other in order to check for out-of-round.
c. Using journal diameter measured above and alphabets stamped on cylinder block, select an undersize bearing by referring to table given below.
Check bearing clearance with newly selected undersize bearing.
Finished journal diameter
44.732 – 44.750 mm (1.7611 – 1.7618 in.)
Measurement should be taken in two directions perpendicular to each other in order to check for out-of-round.
c. Using journal diameter measured above and alphabets stamped on cylinder block, select an undersize bearing by referring to table given below.
Check bearing clearance with newly selected undersize bearing.
New standard undersize crankshaft main bearing specification
| Measured journal diameter | ||||
|---|---|---|---|---|
|
44.7440 – 44.7500 mm
(1.7616 – 1.7618 in.) |
44.7380 – 44.7440 mm
(1.7613 – 1.7616 in.) |
44.7320 – 44.7380 mm
(1.7611 – 1.7613 in.) |
||
|
Alphabets (numbers) stamped
on cylinder block |
A | Red and Pink | Red and Purple | Red and Brown |
| B | Red and Purple | Red and Brown | Red and Green | |
| C | Red and Brown | Red and Green | Red and Black | |
| Undersize bearing to be installed | ||||
Main Bearing Cap No.1 Bolt
Measure each thread diameter main bearing cap No.1 bolts (1) at “A” on 60 mm (2.36 in.) from seat side of flange bolt and “B” on 90 mm (3.54 in.) from seat side of flange bolt by using a micrometer (2).
Calculate difference in diameters (“A” – “B”).
If it exceeds limit, replace with new one.
Main bearing cap No.1 bolt diameter measurement points
“a”: 60 mm (2.36 in.)
“b”: 90 mm (3.54 in.)
Main bearing cap No.1 bolt diameter difference
Limit (“A” – “B”): 0.2 mm (0.008 in.)