Timing Belt: Service and Repair
Timing Belt Train:
REMOVAL
Remove the parts in numerical order shown, paying attention to the following items.
1. Place piston of No. 1 cylinder at top dead center of compression stroke.
Securing Tensioner Temporarily:
2. Move tensioner fully toward water pump and temporarily secure it.
3. If timing belt is to be reused, make an arrow mark which indicates turning direction to ensure that belt is reinstalled in same direction as before.
Preventing Rotation Of Left Silent Shaft:
4. When oil pump sprocket nut is removed, first remove plug at left side of cylinder block and insert a screwdriver to keep left silent shaft in position. Screwdriver used for this purpose should have a shaft 8 mm (.3 in.) thick which can be inserted more than 60 mm (2.36 in).
Removing Timing Belt B:
5. Loosen right silent shaft sprocket mounting bolt unit it can be loosened by hand.
6. 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.
INSPECTION
1. Check belt in detail if following flaws are evident, replace belt with a new one.
Checking Timing Belt:
a. Hardened back surface rubber back surface glossy. Nonelastic and so hard that even if a finger nail is forced into it, no mark is produced.
Checking Timing Belt:
b. Cracked back surface rubber
c. Cracked or exfoliated canvas
d. Cracked tooth bottom
e. Side of belt cracked
f. Cracked canvas
g. Side of belt badly worn
NOTE: Normal belt should have clear-cut sides as if cut with a sharp knife.
h. 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).
i. Missing tooth.
INSTALLATION
1. Install crankshaft sprocket, flange and spacer as shown, while paying attention to their mounting directions.
CAUTION: Pay special attention to direction of flange. If it is installed in wrong direction, a broken belt could result.
2. Temporarily secure tensioner at a position closest to water pump.
3. install end A of spring to predetermined position on tensioner bracket.
4. Install end B of spring to predetermined position on water pump.
5. When spacer is installed to right silent shaft, direct spacer with its chamfered end toward shaft for protection of oil seal.
BELT INSTALLATION PROCEDURE
Aligning Timing Marks:
1. Align timing mark on each sprocket with corresponding timing mark on front case.
2. When timing belt "B" is installed, make certain that tension side has no slack.
Installing Tensioner "B":
3. install tensioner "B" with center of pulley located on left side of mounting bolt and with pulley flange directed toward front of engine.
Adjusting Belt Tension:
4. Lift tensioner "B" with finger tip to tighten timing belt "B" so that its tension side will be taut. 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 overtensioned.
5. Check to ensure that timing marks are in alignment.
6. Check to ensure that when center of span on tension side is depressed with index finger in direction of arrow, deflection of belt is up to specification.
Belt deflection 5 to 7 mm (.2 to .3 in.)
7. Move tensioner fully toward water pump and temporarily secure tensioner.
Mounting Timing Belt:
8. Align timing mark on camshaft sprocket with that on cylinder head.
9. Align timing mark on crankshaft sprocket with that on front case.
10. Align timing mark on oil pump sprocket with that on front case.
Preventing Rotation Of Left Silent Shaft:
11. When timing mark on oil pump pulley is aligned with that on front case, be sure to remove plug on left side of cylinder block and insert a screw driver having shaft 8 mm (.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 in.), turn oil pump sprocket through a turn and realign timing marks. Check to ensure that screwdriver can be inserted more than 60 mm (2.36 in.). Keep screw driver inserted until installation of timing belt is finished.
12. 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.
13. Loosen tensioner mounting bolt and nut. By so doing, tensioner will be moved by spring and will apply tension to belt.
14. Check that portion of belt which is indicated by arrow A to make sure that it is not floating up.
15. Tighten tensioner mounting nut and bolt. 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.
16. Check to ensure that timing marks on all sprockets are in alignment with respective timing marks.
17. Turn crankshaft.
CAUTION: Do not turn crankshaft in reverse direction. Crankshaft should be turned smoothly clockwise.
18. Loosen tensioner mounting nut and bolt.
19. Tighten tensioner mounting nut and bolt. Be sure to tighten fulcrum side nut and bolt in Step 15.
Adjusting Timing Belt Tension:
20. Check to ensure that when center of belt span on tension side and seal line of under cover are held between thumb and forefinger as illustrated, clearance C between belt and seal line is as follows:
Clearance C Approx. 14 mm. (.55 in.)