5. Inspection and servicing of basic engine parts1955.3.1 Piston(1) Piston head and combustion surfaceRemove the carbon that has accumulated onthe piston head and combustion surface,taking care not to scratch the piston. Checkthe combustion surface for any damage.(2) Measurement of piston outside diameter/inspection1) Replace the piston if the outsides of thepiston or ring grooves are worn.2) Measure the outside diameter in the positionof 22mm from the piston bottom in thedirection vertical to the piston pin.If the piston outside diameter exceeds the limit,replace the piston with new one.Selective pairing of cylinder and pistonPiston must be paired with cylinder according tothe below table. The size mark of a piston is shownon the top surface of the piston and the size markof a cylinder block is shown on the non-operatingside of the cylinder block. The service parts ofpistons are provided.(3) Removing the piston pinA floating type piston pin is used in thisengine. The piston pin can be pressed into thepiston pin hole at room temperature (Coat withoil to make it slide easily).Piston outside diameterModel Standard Limit Clearance betweenpiston and cylinder3JH4E 87.950-87.960 87.900 0.045-0.0754JH4E 87.935-87.945 87.885 0.060-0.0904JH4-TE4JH4-HTE 83.930-83.940 83.880 0.065-0.095Piston outside diameter.D2 = 87.955 mmTolerance below + 0.0050 min.below 0-0.005 min.Size mark ML MSCylinder insidediameterD1 = 88.000 mm+0.030 max.+0.020 min. L { Xbelow +0.020+0.010 min. M { {below +0.0100 min. S X {Model Cylinder inside diameterD1 (mm)Piston outside diameter.D2 (mm)3JH4E 88 87.9554JH4E 87.9404JH4-TE4JH4-HTE 84 83.93522 mmPistonbottom008232-00E
