FUSO 4M4 – Engine – CYLINDER HEAD AND VALVE MECHANISM – Inspection before removal

Inspection: Piston projection from upper crankcase top surface

• Set the piston at the top dead center.
• Mark reference points A (five points in total) on the top surface of the upper crankcase as shown in the illustration. Using each of the marks as a zero point, measure the amount of piston projection relative to the zero point (height of measurement point B height of reference point A).
• Make the measurements at the two measurement points B for each cylinder (eight points in total) using the reference point A nearest to each measurement point, and calculate the average value of all the measurements.
• If the average value is out of the standard value range, check the clearance between all relevant parts.
• Select and use a cylinder head gasket that can accommodate the average piston projection (average value of the eight measurements). (See the CYLINDER HEAD AND VALVE MECHANISM section.)

•Inspection: Connecting rod end play
– Measure the end play for every connecting rod.
– If any measurement exceeds the specified limit, replace the defective part(s).

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