GS300 & SC300
- Disconnect negative battery cable. Drain engine coolant. Disconnect control cables from throttle linkage. Remove intake air hose. Remove EGR pipe and gasket. Remove throttle body bracket between throttle body and cylinder head.
- Remove throttle body and intake air connector (pipe between throttle body and air intake chamber) as an assembly. Remove timing belt cover No. 3 (upper outer cover). Remove cylinder head rear cover (small cover on top of cylinder head, near rear end).
- Disconnect spark plug wires from plugs and wire holders. Remove cylinder head covers and gaskets. Rotate crankshaft clockwise until cylinder No. 1 is at TDC of compression stroke. Groove on crankshaft pulley should be aligned with "0" timing mark on timing belt cover, and timing marks on camshaft pulleys should be aligned with timing marks on timing belt cover No. 4 (upper inner cover).
- On GS300, measure and record clearance of intake valves for cylinders No. 1, 2 and 4, and exhaust valves for cylinders No. 1, 3 and 5. See Fig 2. Rotate crankshaft 360 degrees. Measure and record clearance of intake valves for cylinders No. 3, 5 and 6, and exhaust valves for cylinders No. 2, 4 and 6. Go to step 7).
- On SC300, uniformly tighten camshaft bearing cap bolts in sequence to specification. See TORQUE SPECIFICATIONS TABLE at the end of this article. See Fig 1. Measure and record clearance of intake valves for cylinders No. 1 and 4, and exhaust valves for cylinders No. 1 and 5. See Fig 3-9. Rotate crankshaft 240 degrees (2/3 revolution).
- Measure and record clearance of intake valves for cylinders No. 3 and 5, and exhaust valves for cylinders No. 3 and 6. See Fig 3-9. Rotate crankshaft another 240 degrees (2/3 revolution). Measure and record clearance of intake valves on cylinders No. 2 and 6, and exhaust valves on cylinders No. 2 and 4.
- Compare actual clearance with specified clearance. See VALVE CLEARANCE SPECIFICATIONS (GS300 & SC300) table. If clearance is within specification, go to step 11). If clearance is not within specification, rotate crankshaft until camshaft lobe of valve to be adjusted is facing upward, away from lifter shim.VALVE CLEARANCE SPECIFICATIONS
Application (1) In. (mm) Exhaust .010-.014 (.25-.35) Intake .006-.010 (.15-.25) (1) Adjust valves with engine cold. - Rotate adjustment shim until notch is at a 90-degree angle to camshaft (perpendicular), facing spark plug. Using Valve Lifter Press (SST 09248-05011), press valve lifter downward. See Figure. Install Valve Lifter Stopper (SST 09248-05021) between camshaft and valve lifter. Remove valve lifter press. Using a small screwdriver and magnet, remove adjusting shim.
- Using a micrometer, measure thickness of shim removed. Replace removed shim with a shim of different thickness to bring valve clearance to specification. See VALVE CLEARANCE SPECIFICATIONS (GS300 & SC300) table.
- Shims are available in thicknesses of .0984-.1299" (2.50-3.30 mm), in increments of .002" (.05 mm). To install shim, press downward on valve lifter using valve lifter press. Remove valve lifter stopper. Recheck valve clearance after shim is installed.
- To complete installation, reverse removal procedure. Use NEW gaskets as necessary. Tighten nuts and bolts to specification. See TORQUE SPECIFICATIONS TABLE at the end of this article.