Timing Belt
TIMING BELTREMOVAL AND INSTALLATION
Removal Steps 1-16:
Required Special Tools:
^ MB990767: End Yoke Holder
^ MD998716: Crankshaft Wrench
^ MD998719: Pins
REMOVAL SERVICE POINTS
[[A]] AUTO-TENSIONER REMOVAL
1. Remove the upper tightening bolt of the auto-tensioner.
CAUTION: The auto-tensioner rotates centering on the flange bolt due to the rod thrust, so please make sure your finger is not trapped.
2. Slowly loosen the (lower) tightening bolts of the auto-tensioner. Remove the auto-tensioner rod from the tensioner arm and tilt the auto-tensioner to the stopper position.
3. Remove the lower tightening bolt of the auto-tensioner.
[[B]] TIMING BELT REMOVAL
1. Before the timing belt is removed, align the timing marks of the camshaft sprocket and crankshaft sprocket with the Number 1 at the Top Dead Center of the compression stroke.
CAUTION: Water or oil on the belt shortens its life drastically, so the removed timing belt, sprocket, and tensioner must be kept free from oil and water. Do not immerse parts in cleaning solvent.
2. Mark the belt running direction for reference in reinstallation.
NOTE: If there is oil or water on any part, check the front case oil seal, camshaft oil seal, and water pump for leaks.
NOTE: After the timing belt is removed, do not turn the crankshaft sprocket and the camshaft sprocket.
[[C]] IDLER PULLEY REMOVAL
CAUTION: Because of the shallow hexagon hole of the hexagon socket head bolt, firmly insert the tool and carefully work not to damage the hexagon hole.
Remove the idler pulley using a hexagon wrench with 8 mm width across flats.
[[D]] CAMSHAFT SPROCKET BOLT REMOVAL
Use special tools MB990767 and MD998719 to prevent the camshaft sprocket from turning, and then loosen the camshaft sprocket bolt.
INSTALLATION SERVICE POINTS
]]A[[ CAMSHAFT SPROCKET BOLT INSTALLATION
Use special tools MB990767 and MD998719 to prevent the camshaft sprocket from turning, and then tighten the camshaft sprocket bolt.
Tightening torque: 90 ± 10 Nm (65 ± 7 ft-lb)
]]B[[ CRANKSHAFT SPROCKET INSTALLATION
1. Clean the hole in the crankshaft sprocket.
2. Clean and degrease the mating surfaces of the crankshaft sprocket.
NOTE: Degreasing is necessary to prevent decrease in friction on the mating surfaces.
3. Install the crankshaft sprocket to the crankshaft.
]]C[[ IDLER PULLEY INSTALLATION
CAUTION: Because of the shallow hexagon hole of the hexagon socket head bolt, firmly insert the tool and carefully work not to damage the hexagon hole.
Install the idler pulley using a hexagon wrench with 8 mm width across flats.
]]D[[ TIMING BELT INSTALLATION
CAUTION: Remove and install the timing belt, aligning the timing marks of the crankshaft sprocket and the camshaft sprocket with the Number 1 at the Top Dead Center of the compression stroke.
1. Check the timing marks of the crankshaft sprocket and the camshaft sprocket are aligned with the Number 1 at the Top Dead Center of the compression stroke. If they are not, align the timing marks again, paying attention to the interference between the valve and the piston.
2. Install the timing belt on each sprocket in the following sequence.
(1) Install the timing belt on the crankshaft sprocket and then on the water pump pulley, while tightening it to prevent slackness.
(2) Line up the timing marks of the left bank camshaft sprockets.
(3) Install the timing belt on the idler pulley, while taking up the slack.
(4) Install the timing belt on the right bank camshaft sprocket.
(5) Install the timing belt on the tensioner pulley.
3. Check to see that the timing marks of all the sprockets are in a alignment.
4. Using special tool MD998716, rotate the crankshaft a quarter of a turn counterclockwise. Then rotate it back clockwise to verify that all the timing marks are in alignment.
5. Pull out the pin of the auto-tensioner.
6. Rotate the crankshaft two turns clockwise and leave it alone for approximately five minutes.
7. Check that the projection of the rod of the auto-tensioner is within the standard value.
Standard value: 9.1 - 13.4 mm (0.36 - 0.52 inch)
]]E[[ AUTO-TENSIONER INSTALLATION
CAUTION: Always bleed the auto-tensioner of air before installing the auto-tensioner. (Refer to Air bleeding method)
INSPECTION
TIMING BELT
Replace the belt if any of the following conditions exist:
1. Hardening of rubber backing.
Back side should be glossy without resilience and leave no indent when pressed with fingernail.
2. Cracks on rubber back.
3. Cracks or peeling of canvas.
4. Cracks at bottom of ribs.
5. Cracks on belt sides.
6. Abnormal wear of belt sides. Normal wear is indicated if the sides are sharp as if cut by a knife. Abnormal wear is indicated if the sides are ragged.
7. Abnormal wear on teeth.
Initial stage:
Canvas worn (fluffy canvas fibers, rubbery texture gone, white discoloration, canvas texture indistinct)
Final stage:
Canvas worn, exposing rubber (tooth width reduced)
8. Missing tooth.
AIR BLEEDING METHOD
CAUTION:
^ Always use the vertical press and put the auto-tensioner vertically.
^ For breakage prevention, Do not apply the load of 5,000 N (1,124 pound) or more to the rod.
^ Do not press the rod beyond Dimension "A" shown in the illustration.
1. Set the auto tensioner as shown in the illustration.
2. Press the rod slowly down to the lowest point "A" shown in the illustration.
3. Repeat the procedure 2 three times.
4. While the rod is projected at the point "B" shown in the illustration, push the rod with 100 - 200 N (22 - 44 pound). Check the enough stiffness. If the stiffness is not enough, replace the auto tensioner.
5. Press the rod slowly down. Put the pin through the hole and fix it.
CAUTION: After the air bleeding operation has been completed, do not tilt the auto-tensioner to 60° or more from the right angle position.
VALVE CLEARANCE ADJUSTMENT
1. Remove the rocker cover and ignition coil.
CAUTION: Rotate the crankshaft clockwise at any time.
2. Turn the crankshaft clockwise, and align the crankshaft sprocket timing mark with the position shown in the illustration.
3. At that time, check the right and left camshaft sprocket timing marks are in position as shown in the illustration.
4. Measure the valve clearances marked with arrows shown in the illustration.
A: When Number 1 cylinder is on the top dead center of compression stroke.
B: When Number4 cylinder is on the top dead center of compression stroke.
NOTE: The valve clearance adjustment at the exhaust side is not necessary because the auto lash adjuster exists.
5. Using a thickness gauge, adjust the clearance between the valve stem end and the adjusting screw.
Standard value (in cold state): 0.07 - 0.13 mm (0.003 - 0.005 inch)
NOTE: After the engine assembly is installed on the vehicle, check the valve clearance again in the engine warm-up state. Adjust if necessary.
6. Hold the adjusting screw not rotating through a driver and then tighten the rock nut.
7. Rotate the crankshaft one time clockwise and then align the timing mark with the timing mark on the crankshaft sprocket. (Place Number 4 cylinder on the top dead center of compression stroke.)
8. Adjust the valve clearance for the rest of the valves.
9. Install the rocker cover and ignition coil.