Timing Belt: Service and Repair
TIMING BELT REMOVAL
1. Place piston in No.1 cylinder at top dead center on compression stroke.
2. Remove the water pump drive belt and pulley.
3. Remove the crankshaft pulley and the upper and lower timing belt covers.
4. Move the tensioner fully toward the water pump and temporarily secure tensioner.
5. If timing belt is to be reused, make an arrow mark to indicate turning direction to ensure that belt is reinstalled in the same direction as before.
6. Remove the timing belt from the sprockets.
7. When the oil pump sprocket nut is removed, first remove the plug at left side of the cylinder block and insert a screwdriver to keep the left counter balance shaft in position. Screwdriver used for this purpose should have a shaft 8 mm (0.3 in) in diameter which can be inserted more than 60 mm (2.36 in).
8. Remove the oil pump sprocket retaining nut and remove the oil pump sprocket.
9. Loosen the right counter balance shaft sprocket mounting bolt until it can be loosened by hand.
10. Next, remove tensioner "B" and remove timing belt "B."
CAUTION:
- After timing belt "B" has been removed do not attempt loosening bolt, while holding sprocket with pliers etc.
11. Remove the crankshaft sprocket "B" from crankshaft.
TIMING BELT INSPECTION
1. Closely inspect the belt. If following flaws are evident replace the belt with a new one.
(1) Hardened back surface rubber back surface glossy. Non-elastic and so hard that even if a finger nail is forced into it, no mark is produced.
(2) Cracked back surface rubber.
(3) Cracked or peeled canvas.
(4) Cracked tooth bottom.
(5) Side of belt cracked.
(6) Side of belt badly worn.
NOTE: A normal belt should have clear-cut sides as if cut with a sharp knife.
(7) Badly worn teeth.
Initial stage: Canvas on load side tooth flank worn (fluffy canvas fibers, rubber gone and color changed to white and unclear canvas texture).
Last stage: Canvas on load side tooth flank worn down and rubber exposed (tooth width reduced).
(8) Missing tooth
TIMING BELT INSTALLATION
1. Install crankshaft sprocket "B" into crankshaft.
CAUTION:
- Pay special attention to the direction of the flange. If it is installed in the wrong direction a broken belt could result.
2. Lightly apply engine oil to the outer surface of spacer, and then install spacer to the right counter balance shaft. Be sure to install in the direction as shown in illustration.
3. Install counter balance shaft sprocket onto right counter balance shaft, and then tighten flange bolt finger tight.
4. Install timing belt "B" and adjust the belt tension.
5. Tighten the right counter balance shaft sprocket bolt to the specified torque. 34 - 39 Nm (350 - 400 kg) (25 - 29 ft lb).
6. Install flange and crankshaft sprocket onto crankshaft. Be sure to install in the direction as shown in image.
CAUTION:
- Pay attention to direction of flange. If it is installed in wrong direction, a broken belt could result.
7. Install special washer and sprocket bolt to crankshaft, and then tighten the sprocket bolt to the specified torque. 108 - 127 Nm (1,100 - 1,300 kg) (80 - 94 ft lb).
8. Install the camshaft sprocket to the camshaft and tighten bolt to the specified torque. 78 - 98 Nm (800 - 1,000 kg) (58 - 72 ft lb).
9. Install spacer, tensioner and tensioner spring.
10. Install end "A" of spring to predetermined position of tensioner bracket.
11. Install end "B" of spring to predetermined position of water pump.
12. Install the timing belt and adjust the belt tension.
(1) Align timing mark on each sprocket with corresponding timing mark on the front case.
(2) When timing belt "B" is installed make certain that tension side has no slack.
(3) Install tensioner "B" with center of pulley located on the left side of mounting bolt and with pulley flange directed toward front of engine.
(4) Align timing mark on the right counter balance shaft sprocket with the timing mark on the front case.
(5) Lift tensioner "B" to tighten timing belt "B" so that its tension side will be pulled tight. In this condition, tighten bolt to secure tensioner "B." When bolt is tightened use care to prevent shaft from turning together. If shaft is turned together belt will be overtightened.
(6) Check to ensure that timing marks are in alignment.
(7) Check to ensure that when center of span on the tension side is depressed with index finger in direction of arrow, deflection of belt is within specification.
Belt deflection: 5 - 7 mm (0.2 - 0.3 in)
(8) Move tensioner fully toward water pump and temporarily secure tensioner.
(9) Align timing mark on camshaft sprocket with the timing mark on the cylinder head.
(10) Align timing mark on crankshaft sprocket with the timing mark on front case.
(11) Align timing mark on oil pump sprocket with the timing mark on front case.
(12) When timing mark on oil pump pulley is aligned with the timing mark on front case be sure to remove plug on left side of cylinder block and insert a screwdriver having a shaft 8 mm (0.3 in) in diameter. If it can be inserted 60 mm (2.36 in) or more, alignment is correct. If it can be inserted only 25 mm (1.0 in), turn oil pump sprocket one revolution and realign timing marks. Check to ensure that screwdriver can be inserted more than 60 mm (2.36 in). Keep screwdriver inserted until installation of timing belt is finished.
(13) Install timing belt. While making sure that tension side of belt is not slackened, install timing belt onto crankshaft sprocket, oil pump sprocket and camshaft sprocket in that order.
(14) Loosen tensioner mounting bolt and nut. Tensioner will be moved by spring and will apply tension to belt.
(15) Check that portion of belt which is indicated by arrow "A" to make sure that it is not floating up.
(16) Tighten tensioner mounting nut and bolt.
NOTE: Tighten slot side bolt before tightening fulcrum side nut. If fulcrum side nut is tightened earlier, tension bracket will be turned together and belt will be overtensioned.
(17) Check to ensure that timing marks on all sprockets are in alignment with respective timing marks.
(18) Turn the crankshaft clockwise.
CAUTION:
- Do not turn crankshaft In reverse direction. Crankshaft should be turned clockwise only.
(19) Loosen tensioner mounting nut and bolt.
(20) Tighten tensioner mounting nut and bolt.
NOTE: Be sure to tighten fulcrum side nut and bolt in step (16).
(21) Check to ensure that clearance exists when center of belt span on tension side and seal line of under cover are held between thumb and forefinger as shown in image. Clearance "C" between belt and seal line approximately 14 mm (0.55 in).
13. Install the timing belt covers.
14. Install the crankshaft pulley and cranking adapter, and then tighten bolts to the specified torque. 20 - 29 Nm (200 - 300 kg) (14 - 22 ft lb).