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Crankshaft And Main Bearings

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  1. Remove 7 bolts and remove rear oil seal retainer and "O" ring. Using a dial indicator, check crankshaft end play before removing crankshaft from cylinder block. Replace thrust bearings if end play is not within specification. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS  table under ENGINE SPECIFICATIONS. Thrust bearings are on No. 3 journal.
  2. Main bearing caps are numbered 1-5 for location, with No. 1 at timing belt (front) end and No. 5 at drive plate (rear) end. Note that arrows on main bearing caps point toward timing belt end of engine. Remove 10 side main bearing cap bolts located on sides of cylinder block.
  3. Evenly loosen the 20 main bearing cap bolts in sequence, using several steps. See Fig 1. Remove main bearing cap bolts and main bearing caps. Lift crankshaft from cylinder block. Remove thrust bearings from journal No. 3.
  4. Reinstall main bearing caps with bearings to cylinder block, without crankshaft, and tighten bolts to specification. Using cylinder bore gauge, measure inside diameter of main bearings. Main bearing inside diameter should be 2.6372-2.6378 in. (66.985-67.000 mm). Using an outside micrometer, measure outside diameter of crankshaft main bearing journals. Subtract main bearing journal diameter from main bearing inside diameter to determine oil clearance. If clearance exceeds specification, replace bearings and/or crankshaft.
  5. If replacing bearing, ensure size mark on NEW bearing is the same as size mark on original bearing. Main bearing size mark ("1", "2", "3", "4" or "5") is located on back of main bearing. See Fig 2. If size mark on original bearing cannot be determined, add size mark on crankshaft to size mark on cylinder block, and refer to charts in figure to determine size of NEW bearing to be used. See Fig 3.
    Fig 1: Identifying Main Bearing Cap Bolts Loosening & Tightening Sequence
    G00006502Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    Fig 2: Identifying Crankshaft, Cylinder Block & Main Bearing Size Marks
    G93J01805Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    Fig 3: Main Bearing Application Selection Chart
    G00006441Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  6. Cylinder block main bearing bore inside diameter is identified by main bearing bore size mark stamped on cylinder block. See Fig 2. Crankshaft main bearing journal diameter is determined by size mark located on crankshaft counterweight.
  7. Main bearing thickness is also determined by size mark. See MAIN BEARING SPECIFICATIONS  table.
    MAIN BEARING SPECIFICATIONS

    Size Mark Bearing Thickness - In. (mm)
    No. 1 & No. 5 Bearings
    "3" .0981-.0982 (2.492-2.494)
    "4" .0982-.0983 (2.494-2.497)
    "5" .0983-.0985 (2.497-2.502)
    "6" .0985-.0986 (2.502-2.504)
    "7" .0986-.0987 (2.504-2.507)
    No. 2, 3 & 4 Bearings
    "1" .0979-.0980 (2.487-2.489)
    "2" .0980-.0981 (2.489-2.492)
    "3" .0981-.0982 (2.492-2.494)
    "4" .0982-.0983 (2.494-2.497)
    "5" .0983-.0985 (2.497-2.502)
  8. Ensure journal diameter, taper and out-of-round are within specification. Replace crankshaft if not within specification. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS  table under ENGINE SPECIFICATIONS.
  9. Main bearings come in widths of .768 in. (19.5 mm) and .886 in. (22.5 mm). See Fig 4. Install the 2 wide main bearings in No. 1 (timing belt end) and No. 5 (drive plate end) positions. Install the remaining narrow main bearings in all other locations. Ensure upper main bearings installed in cylinder block contain oil holes and oil grooves. Lower main bearings installed in main bearing caps do not have oil holes or grooves.
  10. Use Plastigage to check main bearing oil clearance. Coat threads and under head of main bearing bolts with engine oil. Install main bearing caps and tighten bolts to specification. Remove main bearing caps and measure thickness of Plastigage to determine clearance. If clearance is not within specification, replace bearings with appropriate size to obtain correct clearance.
  11. Install thrust washers on No. 3 main bearing in cylinder block and main bearing cap, with grooved sides facing outward, toward crankshaft. Install crankshaft and main bearing caps. Main bearing caps must be installed with arrow on top of cap pointing toward timing belt end of engine. Ensure main bearing caps are installed in numerical order, with No. 1 at timing belt end of engine and No. 5 at drive plate end.
  12. Install and tighten main bearing cap bolts to specification in sequence, using 2 steps. See Fig 1. See TORQUE SPECIFICATIONS .
  13. Ensure crankshaft end play is within specification. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS  table under ENGINE SPECIFICATIONS. Replace thrust bearing if end play is not within specification.
  14. Install NEW seal washers on the 10 main bearing cap side bolts located on sides of cylinder block. Install bolts and tighten to specification. See TORQUE SPECIFICATIONS .
Fig 4: Identifying Main Bearing Widths
G00050518Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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