Timing chain-measuring wear. Pistons-fitting

Timing chain-measuring wear

NOTE: This procedure must be performed with the timing chain cover removed.

1) Remove the timing chain cover. Refer to Timing Chain Cover in this section for procedure.

(2) To determine if the secondary timing chains are worn, rotate the engine clockwise until maximum tensioner piston extension is obtained. Measure the distance between the secondary timing chain tensioner housing and the step ledge on the piston (Fig.

17). The measurement at point (A) must be less than 15mm (.5906 inches).

(3) If the measurement exceeds the specification the secondary timing chains are worn and require replacement. Refer to Timing Chain and Sprockets in this section for procedure.

Pistons-fitting

BORE GAGE METHOD

(1) To correctly select the proper size piston, a cylinder bore gauge, capable of reading in 0.003 mm (.0001 in.) INCREMENTS is required. If a bore gauge is not available, do not use an inside micrometer.

(2) Measure the inside diameter of the cylinder bore at a point 49.5 mm (1-15/16 inches) below top of bore. Start perpendicular (across or at 90 degrees) to the axis of the crankshaft at point A and then take an additional bore reading 90 degrees to that at point B (Fig. 19).

(3) The coated pistons will be serviced with the piston pin and connecting rod pre-assembled. Tin coated pistons should not be used as replacements for coated pistons.

(4) The coating material is applied to the piston after the final piston machining process. Measuring the outside diameter of a coated piston will not provide accurate results (Fig. 18). Therefore measuring the inside diameter of the cylinder bore with a dial Bore Gauge is MANDATORY. To correctly select the proper size piston, a cylinder bore gauge capable of reading in 0.003 mm (.0001 in.) increments is required.

(5) Piston installation into the cylinder bore requires slightly more pressure than that required for non-coated pistons. The bonded coating on the piston will give the appearance of a line-to-line fit with the cylinder bore.

Fig. 15 Camshaft Sprocket Installation-Left Cylinder Head

1 - TORQUE WRENCH

2 - CAMSHAFT SPROCKET

3 - LEFT CYLINDER HEAD

4 - SPECIAL TOOL 6958 SPANNER WITH ADAPTER PINS 8346

Fig. 16 Camshaft Sprocket Installation-Right Cylinder Head

1 - TORQUE WRENCH

2 - SPECIAL TOOL 6958 WITH ADAPTER PINS 8346

3 - LEFT CAMSHAFT SPROCKET

4 - RIGHT CAMSHAFT SPROCKET

Fig. 17 Measuring Secondary Timing Chains For Stretch

1 - SECONDARY TENSIONER ARM

2 - SECONDARY CHAIN TENSIONER PISTON

Fig. 18 Moly Coated Piston

1 - MOLY COATED

2 - MOLY COATED

Fig. 19 Bore Gauge-Typical

1 - FRONT

2 - BORE GAUGE

3 - CYLINDER BORE

4 - 49.5 MM (1-15/16 in)