- Before servicing the vehicle, refer to the Precautions Section.
- Remove the camshaft from the engine.
Inspect the camshaft bearing journals for damage or binding.
NOTEIf the journals are binding, check the cylinder head for damage. Also check the cylinder head oil holes for clogging.
- Check the camshaft lobe and bearing surfaces for wear and damage. Replace as required.
- Measure the lobe actual wear and replace the camshaft if it is out of limit. The standard value is 0.001 inch (0.0254 mm). The wear limit is 0.010 inch (0.254 mm).
Removal & Installation
- Before servicing the vehicle, refer to the Precautions section.
- Drain the cooling system.
- Drain the engine oil
- Properly relieve the fuel system pressure.
Remove or disconnect the following:
Negative battery cable
Rotate the crankshaft so that the crankshaft timing mark aligns with the 40 degree After Top Dead Center (ATDC) mark on the front cover as shown. Grooves in the camshafts must be toward the inside of the wedge.
Lock the camshafts in place with Camshaft Locking Plates 9104 and 9105.
Remove the timing chain tensioner as shown.
Use a cable tie and secure the timing chain the camshaft sprocket.
- Remove the camshaft sprockets.
- Remove the camshaft locking plate tools.
- Loosen and remove the camshaft bearing cap bolts in the sequence shown.
- Remove the rocker arms and the camshafts.
- Remove the cylinder head bolts in the sequence shown.
Remove the cylinder head.
NOTEThe cylinder head is retained by sixteen bolts. Eight of the bolts are smaller and are at the front of the head.
- Check the cylinder head bolts for signs of stretching. If length exceeds 5.67 inches (144 mm), replace bolts as necessary.
- Lubricate the threads of the bolts with clean engine oil.
- Install the cylinder heads. Use new gaskets and tighten the bolts, in sequence, as follows:
- Install the rocker arms and the camshafts.
Install the camshaft bearing cap bolts in the sequence shown. Tighten the bolts to 11 ft. lbs. (15 Nm), plus an additional 90 degrees.
- Lock the camshafts in place with Camshaft Locking Plates 9104 and 9105.
- Install the camshaft sprockets. Tighten the bolts to 37 ft. lbs. (50 Nm), plus an additional 90 degrees.
- Remove cable tie from timing chain.
- Install the timing chain tensioner. Tighten the bolt to 59 ft. lbs. (80 Nm).
- Remove camshaft locking plates
- Ensure crankshaft is set to 40 degrees ATDC
Install or connect the following:
Exhaust pipes to manifold. Tighten the bolts to 15 ft. lbs. (20 Nm).
- Fill and bleed the cooling system.
- Fill the engine with oil.
- Start the engine and check for leaks.