Timing Belt and Sprockets - REMOVAL & INSTALLATION
(see Figures 1 through 11)
Disconnect the negative battery cable. Remove the timing belt covers.
Remove the timing belt guide from the crankshaft pulley.
Fig. 1: Prior to belt removal, inspect all components and matchmark for installation-4A-GE engine (clic for zoom)
If reusing the timing belt, draw a direction arrow on the belt (in
the direction of engine revolution), and place matchmarks on the pulleys
Loosen the timing belt idler pulley, move it to the left (to take tension off the belt) and tighten its bolt.
Fig. 2: Loosen the idler pulley bolt and push it as far to the left as it will go, tighten it, remove the belt ...
Do not disturb the position of the camshafts or the crankshaft during removal.
Carefully slip the timing belt off the pulleys.
Remove the idler pulley bolt, pulley and return spring.
Fig. 3: ... then remove the idler pulley bolt, pulley, and tension spring-4A-GE engine
Remove the crankshaft timing pulley.
Remove the PCV hose and the valve cover.
Use an adjustable wrench to counterhold the camshaft. Be careful
not to damage the cylinder head. Loosen the center bolt in each camshaft
pulley and remove the pulley. Label the pulleys and keep them clean.
Fig. 4: Secure the camshaft and remove the pulley bolt
Check the timing belt carefully for any signs of cracking or
deterioration. Pay particular attention to the area where each tooth or
cog attaches to the backing of the belt. If the belt shows signs of
damage, check the contact faces of the pulleys for possible burrs or
Check the idler pulley by holding it in your hand and spinning it.
It should rotate freely and quietly. Any sign of grinding or abnormal
noise indicates the pulli AM CHANGING THE TIMING - e401bab.jpge replaced.
Fig. 5: Inspect the smoothness of the idler pulley
Check the free length of the tension spring. Correct length is
1.713 inch. (43.5mm) measured at the inside faces of the hooks. A spring
which has stretched during use will not apply the correcti AM CHANGING THE TIMING - d11ea7f.jpg
the pulley; replace the spring.
Fig. 6: Measure the free length of the tension spring-4A-GE engine
If you can test the tension of the spring, look for 22 lbs. of tension at 50mm of length. If in doubt, replace the spring.
Align the camshaft knock pin and the pulley. Reinstall the
camshaft timing belt pulleys, making sure the pulley fits properly on
the shaft and that the timing marks align correctly. Tighten the center
bolt on each pulley to 43 ft. lbs.(58 Nm). Be careful not to damage the
cylinder head during installation.
Fig. 7: Position the knock pin of the camshafts as shown-4A-GE engine (click for zoom)
Before reinstalling the belt, double check that the crank and
camshafts are exactly in their correct positions. The alignment marks on
the pulleys should align with the cast marks on the head and oil pump.
Reinstall the valve covers with new gaskets and attach PCV hose.
Install the timing belt idler pulley and its tensioning spring. Move the idler to the left and temporarily tighten its bolt.
Carefully observing the matchmarks made earlier, install the timing belt onto the pulleys.
Slowly release tension on the idler pulley bolt and allow the
idler to take up tension on the timing belt. DO NOT allow the idler to
slam into the belt; the belt may become damaged.
Fig. 8: Set the No. 1 cylinder to TDC of the compression stroke-4A-GE engine (click for zoom)
Temporarily install the crankshaft pulley bi AM CHANGING THE TIMING - 7a9a938.jpghe engine
clockwise through two complete revolutions, stopping at TDC. Check that
each pulley aligns with its marks.
Fig. 9: Temporarily tighten the crankshaft pulley bolt, then turn it 2 revolutions from TDC to TDC-4A-GE engine