Camshaft: Service and Repair

CAMSHAFT(S)
REMOVAL
1. Remove the primary timing chain.
2. Remove secondary chain tensioner mounting bolts.

NOTE: Camshaft bearing caps have been marked during engine manufacturing. For example, number one exhaust camshaft bearing is marked "1E>"





3. Slowly loosen camshaft bearing cap bolts in reverse order of installation (Fig. 26).
4. Remove camshaft bearing caps.
5. Remove camshafts, secondary chain, and tensioner together as an assembly.
6. Remove tensioner and camshaft chain from camshafts.
7. Inspect camshafts.

INSPECTION





1. Inspect camshaft bearing journals for damage and binding (Fig. 27). If journals are binding, check the cylinder head for damage. Also check cylinder head oil holes for clogging.
2. Inspect camshaft sprockets for excessive wear. Replace camshafts if necessary
3. Check the cam lobe surfaces for abnormal wear and damage. Replace camshaft if defective. Measure the actual wear (Fig. 27) and replace, if out of limits-standard value is 0.0254 mm (0.001 inch); wear limit is 0.254 mm (0.010 inch).

INSTALLATION

CAUTION: When the timing chain is removed and the cylinder heads are installed, DO NOT rotate the camshafts or crankshaft without first locating the proper crankshaft position. Failure to do so will result in valve and/or piston damage.





1. Assemble camshaft chain on the cams. Ensure that plated links are facing toward the front. Align the plated links to the dot on the camshaft sprockets (Fig. 29).
2. If camshaft chain tensioner is already in the compressed and locked position, proceed to step (4).
3. When the camshaft chain tensioner is removed, it is necessary to compress and lock the tensioner using the following procedures:





a. Place tensioner into a soft jaw vise (Fig. 28).
b. SLOWLY compress tensioner until fabricated lock pin or the equivalent can be inserted into the locking holes.
c. Remove compressed and locked tensioner from the vise.
4. Insert the compressed and locked camshaft chain tensioner in-between the camshafts and chain.
5. Rotate the cams so that the plated links and dots are facing the 12:00 O'clock position (Fig. 29).
6. Install cams to cylinder head. Ensure that rocker arms are correctly seated and in proper positions.
7. Install camshaft bearing caps. Ensure that bearing caps are installed in same position as removed.
8. Tighten cam bearing cap bolts gradually in sequence shown in (Fig. 26) to 12 Nm (105 inch lbs.).
9. Install secondary chain tensioner bolts and tighten to 12 Nm (105 inch lbs.).
10. Remove locking pin from secondary tensioners.
11. Measure camshafts end play.
12. Install the primary timing chain.