TSRM/MK4 Supra/Repair Manual
Repair ManualWiring Diagrams
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EM/Engine Mechanical55 / 139
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ENGINE — ENGINE MECHANICAL — MK4 Supra Engine Mechanical, page 55
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EG–55 ENGINE – ENGINE MECHANICAL Overall Length EM0534 EM0255 (d) Check the valve overall length. Standard overall length: Intake 98.29–98.79 mm (3.8697–3.8894 in.) Exhaust 98.84–99.34 mm (3.8913–3.9110 in.) Minimum overall length: Intake 98.19 mm (3.8657 in.) Exhaust 98.74 mm (3.8874 in.) If the overall length is less than minimum, replace the valve. (e) Check the surface of the valve stem tip for wear. If the valve stem tip is worn, resurface the tip with a grinder or replace the valve. NOTICE: Do not grind off more than the minimum overall length. 8. INSPECT AND CLEAN VALVE SEATS 45° Carbide Cutter P02127 (a) Using a 45° carbide cutter, resurface the valve seats. Remove only enough metal to clean the seats. Width EM01B3 EM0635 Z00375 (b) Check the valve seating position. Apply a thin coat of prussian blue (or white lead) to the valve face. Lightly press the valve against the seat. Do not rotate the valve. (c) Check the valve face and seat for the following: • If blue appears 360° around the face, the valve is concentric. If not, replace the valve. • If blue appears 360° around the valve seat, the guide and face are concentric. If not, resurface the seat. • Check that the seat contact is in the middle of the valve face with the following width: Intake 1.0–1.4 mm (0.039–0.055 in.) Exhaust 1.2–1.6 mm (0.047–0.063 in.) If not, correct the valve seats as follows: • If the seating is too high on the valve face, use 15° and 45° cutters to correct the seat. 45° 15° Width P03966