Setting Camshaft Timing: Overview Oldsmobile Aurora I

Note. Setting camshaft timing is necessary whenever camshaft drive system has been disturbed such that the relationship between any chain and sprocket has been lost. Even when only one sprocket is involved, the timing procedure should be observed since one crankshaft revolution will not confirm correct timing. The camshafts and crankshaft are correctly timed when the relationships shown in Fig. (Scheme 6) exist (timing marks on crankshaft sprocket and intermediate shaft sprocket are aligned and all 4 camshaft drive pins are at a right angle to cylinder head surface).

1. Remove camshaft covers. See «CAMSHAFT COVER»(ref-54816-S03316269272001011700000). Remove front cover. See «FRONT COVER»(ref-54816-S17354095022001011700000). Remove or fully retract all 3 chain tensioners. Remove oil pump. See «OIL PUMP»(ref-54816-S29624071742001011700000) under ENGINE OILING.
2. Primary and secondary chain guides should remain in place. Rotate crankshaft until sprocket drive key is positioned at about 1 o'clock.
3. Set crankshaft and intermediate shaft sprockets into primary drive chain with their timing marks adjacent to each other. (Scheme 6)
4. Install crankshaft and intermediate sprockets over their respective shafts. Rotate crankshaft as necessary to engage crankshaft key in sprocket without changing the timing mark relationship.
5. Install Flywheel Holder (J-39411) to lock crankshaft in position. If engine is on stand, an alternate locking method should be devised. Install intermediate sprocket retaining bolt and tighten to specification. See «TORQUE SPECIFICATIONS»(ref-54816-S08840240192001011700000) table.
6. Route secondary chain for left cylinder head over inner row of intermediate shaft teeth. Route secondary drive chain over chain guide, and install exhaust camshaft sprocket to chain so camshaft drive pin engages sprocket notch marked LE (left head exhaust). There should be no slack in lower section of chain, and camshaft drive pin must be perpendicular to cylinder head face. (Scheme 6)
7. Install intake camshaft sprocket into chain so the sprocket notch marked LI (left head intake) engages camshaft drive pin, while pin remains perpendicular to head face. Minor camshaft positioning adjustments can be made using open-end wrench on hex cast into camshaft. see scheme 5
8. Install sprocket retainer bolts and chain tensioner and tighten to specification. See «TORQUE SPECIFICATIONS»(ref-54816-S08840240192001011700000) table.
9. Route secondary chain for right cylinder head over outer row of intermediate shaft teeth, and repeat steps 6) 8). Right camshaft sprockets are identified RI (right intake) and RE (right exhaust). In addition, RE sprocket must contain camshaft position sensor pick-up.

Scheme 6