Camshaft and lifters — removal, inspection and installation
Warning: Wait until the engine is completely cool before beginning this procedure.
Caution: If the camshaft is being replaced, always install new lifters as well. Do not use old lifters on a new camshaft.
Note: The manufacturer states that the engine should be removed for this procedure.
Removal
1. Have the air conditioning system dis- charged by an automotive air conditioning technician (see the Warning above).
2. Relieve the fuel system pressure (see Fuel and exhaust systems), then disconnect the cable from the negative battery terminal (see Engine electrical systems).
3. Remove the radiator (see Cooling, heating and air conditioning systems).
4. Remove the air conditioning condenser (see Cooling, heating and air conditioning systems).
5. Remove the auxiliary automatic trans- mission fluid cooler, if equipped.
6. Disconnect the power steering cooler and move it aside, if equipped.
7. Remove the valve covers (see Valve covers — removal and installation).
8. Remove the intake manifold (see Intake manifold and Valve Lifter Oil Manifold (VLOM) — removal and installation).
9. Remove the rocker arms and pushrods (see Rocker arms and pushrods — removal, inspection and installation).
10. Remove the timing chain and camshaft position actuator (see Timing chain and sprockets — removal, inspection and installation).
11. Remove the cylinder heads (see Cylinder heads — removal and installation).
12. Before removing the lifters, arrange to store them in a clearly labeled box to ensure that they’re reinstalled in their original locations.
13. Remove the lifter retainers and lifters and store them where they won’t get dirty (see illustrations). DO NOT attempt to withdraw the camshaft with the lifters in place.
13.13a The roller lifters are held in place by retainers — remove the retainer bolts and remove the retainers and the lifters as an assembly – note that each retainer houses four individual lifters and they must be installed back in their original locations if they’re going to be reused
13.13b Once the lifters and retainers are removed from the block they can be marked (for location and installation purposes) and inspected
14. If the lifters are built up with gum and varnish they may not come out with the retainer. If so, there are several ways to extract the lifters from the bores. A special tool designed to grip and remove lifters is manufactured by many tool companies and is widely available, but it may not be required in every case. On newer engines without a lot of varnish buildup, the lifters can often be removed with a small magnet or even with your fingers. A machinist’s scribe with a bent end can be used to pull the lifters out by positioning the point under the retainer ring in the top of each lifter.
Caution: Don’t use pliers to remove the lifters unless you intend to replace them with new ones. The pliers will damage the precision machined and hardened lifters, rendering them useless.
15. Remove the bolts and the camshaft retainer plate, noting which direction faces the block (see illustration).
13.15 Remove the bolts and take off the camshaft retainer plate, noting which side faces the block
16. Thread a bolt into the camshaft sprocket bolt hole to use as a handle when removing the camshaft from the block.
17. Carefully and slowly pull the camshaft out. Support the camp near the block so the lobes don’t nick or gouge the bearings as it’s withdrawn.
Inspection
Camshaft lobe lift check
18. Measure the camshaft lobe height and the base circle (see illustrations). The difference between the two measurements is the lobe lift (lobe height — base circle = lobe lift). Record this figure for future reference and repeat the check on the remaining camshaft lobes.
13.18a If the camshaft is removed from the engine, lobe lift can be obtained by measuring camshaft lobe height …
13.18b … and by measuring the camshaft base circle — the difference between the two measurements equals lobe lift
19. After the lobe lift check is complete, compare the results to the values listed in this Chapter’s Specifications. If the lobe lift is 0.002 inch less than specified, cam lobe wear has occurred and a new camshaft should be installed.
Camshaft bearing journals, lobes and bearings
20. After the camshaft has been removed from the engine, cleaned with solvent and dried, inspect the bearing journals for uneven wear, pitting and evidence of seizure. If the journals are damaged, the bearing inserts in the block are probably damaged as well. Both the camshaft and bearings will have to be replaced.
Note: Camshaft bearing replacement requires special tools and expertise that place it beyond the scope of the average home mechanic. The tools for bearing removal and installation are available at stores that carry automotive tools, possibly even found at a tool rental business.
It is advisable though, if the bearings are bad and the procedure is beyond your ability, take the engine block to an automotive machine shop to ensure that the job is done correctly.
21. Measure the bearing journals with a micrometer to determine if they are excessively worn or out-of-round (see illustration).
13.21 Check the diameter of each camshaft bearing journal to pinpoint excessive wear and out-of-round conditions
22. Check the camshaft lobes for heat discoloration, score marks, chipped areas, pitting and uneven wear. If the lobes are in good condition and if the lobe lift measurements recorded earlier are as specified, the camshaft can be reused.
Lifters
23. Clean the lifters with solvent and dry them thoroughly without mixing them up. Check each lifter wall and pushrod seat and for score marks and uneven wear (see illustration). If the lifter walls are damaged or worn (which is not very likely), inspect the lifter bores in the engine block as well. If the push-rod seats are worn, check the pushrod ends.
13.23 Check the pushrod seat in the top of each lifter for wear
24. Check the rollers carefully for wear and damage and make sure they turn freely without excessive play (see illustration).
13.24 The roller on hydraulic roller lifters must turn freely — check for wear and excessive play as well
25. Used roller lifters cannot be reinstalled with a new camshaft, but the original camshaft can be used if new lifters are installed. Always use new lifters when installing a new camshaft.
Installation
26. Lubricate the camshaft bearing journals and cam lobes with camshaft and lifter assembly lube (see illustration).
13.26 Be sure to apply camshaft assembly lube to the cam lobes and bearing journals before installing the camshaft
27. Slide the camshaft into the engine. Support the cam near the block and be careful not to scrape or nick the bearings.
28. Apply non-hardening thread-locking compound to two thirds of the threads on the camshaft retainer bolts, then allow to cure for ten minutes before installing the bolts.
29. Turn the camshaft until the dowel pin is in the 3 o’clock position, install the camshaft thrust plate and tighten the bolts to the torque listed in this Chapter’s Specifications. Make sure the gasket surface on the camshaft thrust plate and the engine block are free from oil and dirt.
30. Install the timing chain and sprockets (see Timing chain and sprockets — removal, inspection and installation). Also install the camshaft position sensor using a new 0-ring (see Emissions and engine control systems).
31. Lubricate the lifters with clean engine oil and install them in the lifter retainers. Be sure to align the flats on the lifters with the flats in the lifter retainers. Install the retainer and lifters into the engine block as an assembly. If the original lifters are being reinstalled, be sure to return them to their original locations. If a new camshaft is being installed, install new lifters as well. Tighten the lifter retainer bolts to the torque listed in this Chapter’s Specifications.
32. The remainder of installation is the reverse of removal.
33. Before starting and running the engine, refill the cooling system, change the oil and install a new oil filter (see Tune-up and routine maintenance).