Contents: Selection of inserts ↓ Main bearings ↓
Causes of bearing wear
1. Reduction of the metal's tensile strength; jagged scratches
2. Incorrectly planted; bright (polished) stripes
3. Scratched with dirt; the dirt has eaten into the surface
4. Lack of oil; the top layer has worn off
5. Excessive wear; the top layer has worn off over the entire surface
6. The bearing is deformed; the top layer has worn off in a circle
Even though old bearing shells are replaced with new ones during engine overhaul, it is necessary to carefully inspect the old shells. Inspection of the shell can reveal the cause of its wear.
[The original source is located on the website: ToyotaMan]
Bearing damage occurs due to lack of lubrication, dirt and other foreign particles, engine overload and corrosion. In any case, the cause of bearing damage must be eliminated before starting engine assembly.
Selection of inserts
To select the correct bearings, use the lubrication gap size, which can be measured using a plastic measuring tape. If you have any problems selecting bearings, contact a specialist.
Main bearings
Dimensions required to determine the thickness of main bearing shells (4-cylinder engines)
The main bearing dimensions for 4-cylinder engines are stamped on the mating surface of the oil pan and on the cylinder block (A), the main bearing journal dimensions are stamped on the crankshaft counterweight (B). For 6-cylinder engines, the bearing dimensions are stamped on the cylinder block above the crankshaft, and the bearing journal dimensions are stamped on the first crankshaft counterweight.
By adding the corresponding numbers on the block and on the crankshaft, you will get the required size of the liner for a four-cylinder engine. To select liners for six-cylinder engines, use the table.
Sum | |||||
| The number on the cylinder block (A) plus the number on the crankshaft (B) | 0 – 5 | 6 – 11 | 12 – 17 | 18 – 23 | 24 – 28 |
| Use insert N | 3 | 4 | 5 | 6 | 7 |
Example: The number on the cylinder block 06 + the number on the crankshaft 08 add up to 14 – use insert N5.