Camshaft: Service and Repair

Camshaft replacement requires separation of the camshaft sprocket and camshaft. In order to maintain camshaft, intermediate shaft and crankshaft timing, the timing belt should remain indexed on the camshaft sprocket while the assembly is suspended under light tension.

When removing camshaft sprocket from camshaft, adequate tension on sprocket and belt assembly must be maintained to prevent the timing belt from disengaging from the intermediate or crankshaft timing sprockets. Failure to maintain adequate tension on timing belt may result in incorrect engine timing.
1. Remove valve cover and curtain.
2. Mark rocker arms for installation reference.

Camshaft Bearing Cap Removal:

3. Evenly loosen camshaft bearing bolts in sequence shown until all bolts have been loosened 3-4 turns.
4. Tap rear of camshaft with suitable mallet to break caps free.
5. Continue loosening bearing cap bolts, ensuring camshaft does not cock, then remove bearing caps and camshaft. Loosen bearing cap bolts evenly. If camshaft cocks in bearing bores, bearing surfaces may be damaged.
6. With caps removed from engine, check oil holes for obstructions. Some engines may be equipped with oversize camshaft bearings. Engines with oversize camshaft bearings can be identified by green markings on cylinder head and camshaft at AIR pump side of engine.
7. Check camshaft lobe height in center (contact area) and on shoulders of lobe. If difference in reading exceeds .010 inch (.25 mm), camshaft should be replaced.
8. Install rocker arms in original positions, then position camshaft in bearing saddles of cylinder head.
9. Apply suitable sealant to bearing cap Nos. 1 and 5.

Camshaft Bearing Cap Installation:

10. Align caps in proper sequence, with No. 1 cap at timing belt end and No. 5 cap at flywheel end of engine, and ensure arrows on caps 1, 2, 3 and 4 point toward timing belt. Install caps before installing camshaft seals.
11. Tighten cap bolts to specifications. Tighten cap bolts evenly in crossing pattern to ensure camshaft remains properly aligned.
12. Install camshaft seals.