The camshaft journals are supported by bearings machined directly into the aluminum-alloy cylinder heads.
With the camshafts removed, inspect the bearings for the following conditions:
Excessive scoring or pitting
- If any of the above conditions exist on the camshaft bearings, replace the cylinder head.
- Inspect the camshaft sprocket locating pin for damage or wear.
- Inspect the threads for the camshaft sprocket bolt.
Inspect the camshaft lobes and journals for the following conditions:
Excessive scoring or pitting.
Inspect the left intake camshaft for the following additional conditions:
Excessive wear on the sealing surface for the camshaft seal.
- If any of the above conditions exist on the camshaft, replace the camshaft.
Measure the camshaft journals for diameter and out-of-round using an outside micrometer:
If the diameter is smaller than 26.948 mm (1.061 in), replace the camshaft.
- Measure the camshaft runout using tool J7872 or equivalent.
- Measure the camshaft thrust wall width for wear using an inside micrometer.
Measure the camshaft thrust wall surface for runout using tool J7872.
- If the camshaft is damaged or worn beyond specifications, replace the camshaft. No machining of the camshaft is allowed.
Measure the camshaft lobes for wear using tool J7872.
Place the tool with the indicator tip on the base circle (2) of the camshaft lobe.
The specifications for lift are as follows:
1999, V.I.N. Y-Intake camshaft: 8.6mm (0.339 in.); Exhaust camshaft: 8.6mm (0.339 in.)
- If the indicated measurement is significantly lower than these specifications, replace the camshaft or engine performance will be reduced.
Removal & Installation
- Before servicing the vehicle, refer to the Precautions Section.
- Remove both camshaft covers.
- Secure the camshaft sprockets to the timing chain by installing tie wraps through the camshaft sprocket holes.
- Working behind the sprockets, install camshaft Chain Holder J38822 so that it is positioned between the chain tensioner and guide. Apply tension to the tool by tightening the tension adjusting screw.
Remove or disconnect the following:
Both camshaft sprocket bolts
- Alternately loosen the camshaft bearing cap screws a few turns at a time until all valve spring pressure has been released.
- Remove the bolts and bearing caps.
- Remove the camshaft.
- Lubricate the camshaft lobes and camshaft journals with clean engine oil.
- Position the camshaft bearing caps in the cylinder head and loosely install the bolts.
- Tighten the camshaft bearing cap bolts in the sequence shown, to 44 inch lbs. (5 Nm), plus 30 degrees.
- Using the hex cast into the camshaft, position the camshafts to accept the camshaft sprockets.
- Install the camshaft sprockets onto the camshafts. Torque the bolts to 89 ft. lbs. (120 Nm).
- Remove the Chain Holder J38822 and the tie wraps.
Install the left and right camshaft covers.