Timing Belt: Service and Repair

Fig. 5 Aligning Timing Marks:

REMOVAL

1. Disconnect battery ground cable.
2. Disconnect accelerator cable from throttle body.
3. Remove undercover.
4. Using a wood block and a jack, place wood block on engine oil pan and raise engine only enough to relieve tension on top engine mount, then remove mount and bracket.
5. Remove engine drive belts. Prior to removing water pump drive belt, loosen water pump pulley bolts.
6. Remove crankshaft pulley.
7. Remove upper and lower timing covers.
8. Remove tensioner pulley and bracket.
9. Disconnect PCV and breather hoses, then remove center cover, spark plug wires and rocker cover.
10. Rotate crankshaft clockwise to bring No. 1 cylinder to top dead center compression stroke. Rotate crankshaft only in clockwise direction. The No. 1 cylinder is at top dead center compression stroke when the timing marks on camshaft sprockets are aligned with upper surface of cylinder head and dowel pins on camshaft sprockets are facing up as shown, Fig. 5.
11. Remove auto tensioner and pulley.
12. Remove timing belt. If timing belt is to be reused, mark timing belt indicating direction of rotation.
13. Remove crankshaft sprocket spacer and flange, camshaft sprockets, oil pump sprocket and timing belt tensioner as needed.
14. Inspect belt and replace if any of the following conditions are noted:
a. Hardened back surface rubber with back surface glossy, non-elastic and so hard that no mark is produced when fingernail is forced into surface.
b. Cracked back surface rubber.
c. Cracked or separated canvas.
d. Cracks at tooth bottom or side of belt.

Fig. 17 Installing Crankshaft Sprocket And Flange:

INSTALLATION

1. Install spacer, flange and crankshaft sprocket. Ensure crankshaft sprocket and flange are correctly installed as shown in Fig. 17.
2. Install oil pump sprocket, torquing attaching nut to specifications.
3. Install camshaft sprockets. Using a wrench, hold the camshaft at the hexagonal portion (between No. 2 and No. 3 journals) and tighten attaching bolt. Locking the camshaft sprocket with a tool may damage the sprocket.

Fig. 18 Aligning Auto Tensional Rod:

4. Install auto tensioner. If tensioner rod is fully extended, proceed as follows:
a. Position auto tensioner level in a soft jawed vise. If plug at bottom of tensioner protrudes, apply a plain washer to prevent the plug from direct contact with vise.
b. Slowly push tensioner rod in, using the vise, until set hole (A) is aligned with hole (B) in the tensioner cylinder, Fig. 18.
c. Insert a wire .055 inch (1.4 mm) in diameter into the set holes, then remove auto tensioner from the vise.
d. Install auto tensioner. Leave the wire installed in the auto tensioner.
5. Install tensioner pulley onto tensioner arm, position the hole in pulley shaft to the left of the center bolt, then tighten center bolt finger tight.

Fig. 6 Adjusting Jet Valve Clearance:

Fig. 19 Positioning Camshaft Sprocket Timing Marks:

6. Rotate camshaft sprockets so that their dowel pins are located on top, then align the timing marks facing each other with the top surface of cylinder head, Fig. 6. When exhaust camshaft is released, it will rotate one tooth in the counterclockwise direction. This should be taken into account when installing timing belt on sprockets.
NOTE: The camshaft sprockets are interchangeable and have two sets of timing marks. When the sprocket is mounted on the exhaust camshaft, use the timing mark on the right with dowel pin hole on top. For the intake sprocket, use the mark on the left with dowel pin hole on top, Fig. 19.
7. Align camshaft sprocket and oil pump sprocket timing marks as shown, Fig. 5.

Fig. 20 Installing Timing Belt:

8. Install timing belt as follows:
a. Install timing belt around intake camshaft sprocket, Fig. 20, and retain using a suitable spring clip.
b. Install timing belt around exhaust camshaft sprocket, aligning timing marks with cylinder head top surface using two wrenches. Retain belt in position using a suitable spring clip.
c. Install timing belt around idler pulley, oil pump sprocket, crankshaft sprocket and tensioner pulley.
d. Remove spring clips retaining timing belt.
e. Gently raise tensioner pulley in direction shown by arrow in Fig. 20, so belt does not sag, then temporarily tighten center bolt.

Fig. 21 Tightening Tensioner Pulley:

Fig. 22 Adjusting Timing Belt Tension:

Fig. 23 Checking Timing Belt Tension:

9. Adjust timing belt tension as follows:
a. Rotate crankshaft 1/4 turn counterclockwise, then rotate clockwise to move No. 1 cylinder to top dead center.
b. Loosen tensioner pulley center bolt, then using wrench tool No. MD998752 or equivalent, and a torque wrench, apply a torque of 1.88 - 2.03 lb-ft, Fig. 21. Use a torque wrench capable of measurement within a range of 0-2.2 lb-ft. If vehicle body interferes with torque wrench, use a jack to slightly raise engine.
c. Holding tensioner pulley with the tool, tighten tensioner pulley center bolt.
d. Screw set screw tool No. MD998738 or equivalent, into left engine support bracket until end of tool makes contact with tensioner arm, Fig. 22. Turn the tool enough to relieve tension on auto tensioner rod, then remove set wire previously installed in auto tensioner.
e. Remove set screw tool.
f. Rotate crankshaft clockwise two complete turns, then let sit for 15 minutes.
g. Measure clearance (A) between tensioner arm and auto tensioner body, Fig. 23. If clearance is not 0.15 - 0.18 inch (3.8 - 4.5 mm), repeat steps a-g until clearance is correct.
h. If clearance (A) cannot be measured with engine in vehicle, screw in set screw tool No. MD998738 or equivalent, until end of tool makes contact with tensioner arm.
i. Starting in this position, count the number of turns of the tool required to bring tensioner arm in contact with auto tensioner body. Ensure contact is made within 2.5-3 turns.
j. Install rubber plug into timing belt rear cover.
10. Reverse procedure to install remaining components, noting the following:
a. When installing rocker cover, apply sealant No. 4318034 or equivalent to semi-circular packing.