Crankshaft & Main Bearings
- Remove main bearing cap side bolts (hexagon bolts) from side of cylinder block in sequence. Perform STEP 1. See Fig 1. Remove main bearing caps side bolts and seal washers.
- Remove main bearing cap-to-cylinder block bolts (12-point bolts) from cylinder block in sequence. Perform STEP 2. See Fig 1.
- Note location of main bearing caps. Main bearing caps are numbered on top of cap for location with No. 1 at timing belt end of engine and No. 4 at drive plate end. Arrow on top of main bearing cap must point toward timing belt end of engine. Remove main bearing caps, crankshaft, main bearings and thrust bearings.
- Cylinder block main bearing bore inside diameter is determined by size mark stamped on front of cylinder block. See Fig 2. Left size mark indicates No. 1 main bearing bore and far right size mark indicates No. 4 main bearing bore.
- Crankshaft journal diameter is determined by size mark located on crankshaft counterweight. See Fig 2. Ensure journal diameter, taper and out-of-round are with within specification. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS under ENGINE SPECIFICATIONS.
- Main bearing size mark is located on side of main bearing. See Fig 2. If replacing main bearing, ensure size mark on replacement main bearing is the same as size mark on original main bearing.
- If size mark on original main bearing cannot be obtained, use size marks on cylinder block and crankshaft to determine size mark of main bearing to be used. See Fig 3. Main bearing thickness is determined by size mark. See MAIN BEARING SPECIFICATIONS .MAIN BEARING SPECIFICATIONS
Size Mark Bearing Thickness - In. (mm) 1 .0979-.0980 (2.486-2.489) 2 .0980-.0981 (2.489-2.492) 3 .0981-.0982 (2.492-2.495) 4 .0982-.0983 (2.495-2.498) 5 .0983-.0985 (2.498-2.501) Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- Use Plastigage to check main bearing oil clearance. Coat threads of main bearing bolts and bolt head-to-main bearing cap area with engine oil. Install .882" (22.40 mm) wide main bearings in No. 1 (timing belt end) and No. 4 (drive plate end) positions. Install narrow main bearings in all other locations.
- Ensure all main bearings installed in cylinder block contain oil holes. Lower main bearings, installed in main bearing caps, do not have oil holes.
- Install thrust bearings on No. 2 main bearing in cylinder block and main bearing cap with grooved sides facing outward, toward crankshaft. Install crankshaft and main bearing caps.CAUTION: 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. 4 at drive plate end.
- Install and tighten main bearing cap-to-cylinder block bolts (12-point bolts) to specification in sequence using several steps. Perform STEP 1. See Fig 4. See TORQUE SPECIFICATIONS .NOTE: NEW seal washers must be installed on main bearing cap side bolts (hexagon bolts) during final assembly.
- Install and tighten main bearing cap side bolts (hexagon bolts) to specification in sequence using several steps. Perform STEP 2. See Fig 4. See TORQUE SPECIFICATIONS .
- Ensure crankshaft end play and main bearing oil clearance are within specification. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS under ENGINE SPECIFICATIONS. Replace thrust bearing if crankshaft end play is not within specification.
- Install NEW seal washers on main bearing cap side bolts (hexagon bolts) during final assembly.