GM Cadillac 1967-1989 Repair Guide

Camshaft

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REMOVAL & INSTALLATION



See Figures 1 and 2

Except 6-252, 1986 8-250, 307 and 8-350 EFI & Diesel Engines

If equipped with air conditioning, the system must be discharged before the camshaft is removed (refer to Routine Maintenance ). The condenser must also be removed from the car.

  1. Disconnect the battery.
  2.  
  3. Drain and remove the radiator.
  4.  
  5. Disconnect the fuel line at the fuel pump. Remove the pump on carbureted models.
  6.  
  7. Disconnect the throttle cable and the air cleaner.
  8.  
  9. Remove the alternator belt, loosen the alternator bolts, and move the alternator to one side.
  10.  
  11. Remove the power steering pump from its brackets and move it out of the way.
  12.  
  13. Remove the air conditioning compressor from its brackets and move the compressor out of the way without disconnecting the lines.
  14.  
  15. Disconnect the hoses from the water pump.
  16.  
  17. Disconnect the electrical and vacuum connections.
  18.  
  19. Mark the distributor as to location in the block. Remove the distributor. Remove the crankshaft pulley and the hub attaching bolt. Remove the crankshaft hub.
  20.  
  21. Remove the engine front cover.
  22.  
  23. Remove the valve covers.
  24.  
  25. Remove the intake manifold.
  26.  
  27. Mark the lifters, pushrods, and rocker arms as to location so that they may be installed in the same position. Remove these parts.
  28.  
  29. If the car is equipped with air conditioning, discharge the air conditioning system and remove the condenser.
  30.  
  31. Remove the fuel pump eccentric, camshaft gear, oil slinger, and timing chain. Remove the camshaft thrust plate (on front of camshaft) if equipped.
  32.  
  33. Carefully remove the camshaft from the engine.
  34.  

To install:
  1. Inspect the shaft for signs of excessive wear or damage.
  2.  
  3. Liberally coat camshaft and bearings with heavy engine oil or engine assembly lubricant and insert the cam into the engine.
  4.  
  5. Align the timing marks on the camshaft and crankshaft gears. See Timing Chain Replacement and Valve Timing for details.
  6.  
  7. Install the distributor using the locating marks made during removal. If any problems are encountered, see Distributor Installation.
  8.  
  9. Reverse the removal procedure but pay attention to the following points:
    1. Install the timing indicator before installing the power steering pump bracket.
    2.  
    3. Install the flywheel inspection cover after installing the starter.
    4.  
    5. Replace the engine oil and radiator coolant.

      Click image to see an enlarged view

      Fig. Fig. 1: Camshaft and oil gallery plugs at rear of block



      Click image to see an enlarged view

      Fig. Fig. 2: Diesel injection pump drive gear

    6.  

  10.  

6-252 Engine
  1. Remove intake manifold.
  2.  
  3. Remove valve covers.
  4.  
  5. Remove rocker arm and shaft assemblies, push rods and valve lifters. Mark parts as necessary and keep pushrods in order for later assembly.
  6.  
  7. Remove timing chain cover, timing chain and sprocket.
  8.  
  9. Carefully slide camshaft forward, out of the bearing bores, working slowly to avoid marring the bearing surfaces. Remove camshaft.
  10.  

To install:
  1. Liberally coat the entire cam with a heavy engine oil or a lubricant specially formulated for engine rebuilding. Slowly slide the camshaft into the engine block, exercising extreme care not to damage the cam bearings.
  2.  
  3. Reassemble the engine in the reverse order of removal.
  4.  

1986 8-250
  1. Remove the engine from the vehicle as detailed earlier in this section.
  2.  
  3. Remove the front cover and timing chain assembly.
  4.  
  5. Remove the valve lifters.
  6.  
  7. Grasp the end of the camshaft and carefully slide it forward until it clears the engine.
  8.  

Threading a large bolt into the end of the camshaft will facilitate removal.


WARNING
Extreme care must be exercised to prevent the camshaft lobes from scratching the bearings!

To install:
  1. Inspect the camshaft and its bearing for excessive wear, flaking or scoring.
  2.  

If a new camshaft is required, the valve lifters and the driveshaft driven gear must be replaced also.

  1. Coat the camshaft, bearing journals and distributor drive gear with engine oil.
  2.  
  3. Carefully slide the camshaft back into the cylinder block.
  4.  
  5. Install the timing chain and the valve lifters. Install the front cover and related components.
  6.  
  7. Install the engine into the vehicle.
  8.  

8-307
  1. Drain the engine coolant.
  2.  
  3. Remove the upper radiator baffle. Disconnect the upper radiator hose at the water outlet and position it out of the way. Remove the upper radiator hose support clamp.
  4.  
  5. Disconnect the transmission cooler lines at the radiator and position them out of the way.
  6.  
  7. Remove the upper radiator support and then remove the radiator.
  8.  
  9. Remove the air cleaner.
  10.  
  11. Tag and disconnect the throttle cable.
  12.  
  13. Remove the drive belts and then remove the A.I.R. pump pulley. Remove the fan, fan clutch and the water pump pulley.
  14.  
  15. Loosen the alternator bracket and swivel the alternator over and out of the way.
  16.  
  17. With the hydraulic lines still attached, remove the power steering pump and position it out of the way.
  18.  
  19. Move the air conditioning compressor mounting bracket. With the lines still attached, move the compressor aside far enough to provide access to the front of the cylinder block.
  20.  
  21. Disconnect and remove the thermostat bypass hose.
  22.  
  23. Tag and disconnect all electrical leads and vacuum lines which may interfere with camshaft removal.
  24.  
  25. Remove the A.I.R. pump.
  26.  
  27. Remove the distributor as detailed previously in this section. Leave the cap and wires attached and just move it aside.
  28.  
  29. Remove the crankshaft pulley and hub.
  30.  
  31. Remove the fuel pump.
  32.  
  33. Remove the front cover.
  34.  
  35. Remove the cylinder head covers.
  36.  
  37. Remove the intake manifold complete with its gasket and seals.
  38.  
  39. Remove all cylinder head valve train components. Remove the valve lifters, guides and retainer.
  40.  
  41. Discharge the air conditioning system as outlined in Routine Maintenance and remove the condenser.
  42.  
  43. Remove the camshaft thrust button and spring.
  44.  
  45. Remove the fuel pump eccentric.
  46.  
  47. Remove the camshaft timing gear along with the timing chain.
  48.  
  49. Remove the camshaft retaining plate and the flange adapter.
  50.  
  51. Carefully slide the camshaft out from the cylinder block.
  52.  

To install:
  1. Coat the camshaft and bearing journals with clean engine oil.
  2.  
  3. Replace the oil filter.
  4.  
  5. Slide the camshaft into the cylinder block. Install the flange adapter and retainer plate.
  6.  
  7. Install the timing chain and sprockets as detailed earlier in this section.
  8.  
  9. Installation of the remaining components is in the reverse order of removal. Road test the vehicle and check for leaks.
  10.  

8-350 EFI & Diesel Engine

If equipped with air conditioning, the system must be discharged before the camshaft is removed (refer to Routine Maintenance ). The condenser must also be removed from the car.

Removal of the camshaft on the diesel also requires removal of the injection pump drive and driven gears, removal of the intake manifold, disassembly of the valve lifters, and retiming of the injection pump.

  1. Disconnect the negative battery cables. Drain the coolant. Remove the radiator.
  2.  
  3. Remove the intake manifold and gasket and the front and rear intake manifold seals. Refer to the Intake Manifold removal and installation procedure.
  4.  
  5. Remove the balancer pulley and the balancer. See Caution under Diesel Engine Front Cover removal and installation, above. Remove the engine front cover using the appropriate procedure.
  6.  
  7. Remove the valve covers. Remove the rocker arms, pushrods and valve lifters; see the procedure earlier in this section. Be sure to keep the parts in order so that they may be returned to their original positions.
  8.  
  9. Remove the camshaft sprocket retaining bolt, and remove the timing chain and sprockets, using the procedure outlined earlier.
  10.  
  11. Position the camshaft dowel pin at the 3 o'clock position.
  12.  
  13. Push the camshaft rearward and hold it there, being careful not to dislodge the oil gallery plug at the rear of the engine. Remove the fuel injection pump drive gear by sliding it from the camshaft while rocking the pump driven gear.
  14.  
  15. To remove the fuel injection pump driven gear, remove the pump adapter, the snapring, and remove the selective washer. Remove the driven gear and spring.
  16.  
  17. Remove the camshaft by sliding it out the front of the engine. Be extremely careful not to allow the cam lobes to contact any of the bearings, or the journals to dislodge the bearings during camshaft removal. Do not force the camshaft, or bearing damage will result.
  18.  
  19. If either the injection pump drive or driven gears are to be replaced, replace both gears.
  20.  

To install:
  1. Coat the camshaft and the cam bearings with a heavyweight engine oil, GM lubricant #1052365 or the equivalent.
  2.  
  3. Carefully slide the camshaft into position in the engine.
  4.  
  5. Fit the crankshaft and camshaft sprockets, aligning the timing marks as shown in the timing chain removal and installation procedure, above. Remove the sprockets without distributing the timing.
  6.  
  7. Install the injection pump driven gear, spring, shim, and snapring. Check the gear end play. If the end play is not within 0.002-0.006 in. (0.05-0.15mm) through 1979, and 0.002-0.015 in. (0.05-0.38mm) on 1980 and later, replace the shim to obtain the specified clearance. Shims are available in 0.003 in. increments, from 0.080 in. to 0.115 in.
  8.  
  9. Position the camshaft dowel pin at the 3 o'clock position. Align the zero marks on the pump drive gear and pump driven gear. Hold the camshaft in the rearward position and slide the pump drive gear onto the camshaft. Install the camshaft bearing retainer.
  10.  
  11. Install the timing chain and sprockets, making sure the timing marks are aligned.
  12.  
  13. Install the lifters, pushrods and rocker arms. See Rocker Arm Replacement, Diesel Engine for lifter bleed down procedures. Failure to bleed down the lifters could bend valves when the engine is turned over.
  14.  
  15. Install the injection pump adapter and injection pump. See the appropriate sections under Fuel System above for procedures.
  16.  
  17. Install the remaining components in the reverse order of removal.
  18.  

CAMSHAFT INSPECTION



Completely clean the camshaft with solvent, paying special attention to cleaning the oil holes. Visually inspect the cam lobes and bearing journals for excessive wear. If a lobe is questionable, have the cam checked at a reputable machine shop; if a journal or lobe is worn, the camshaft must be reground or replaced. Also have the camshaft checked for straightness on a dial indicator.

If a cam journal is worn, there is a good chance that the bearings are worn as well.

CAMSHAFT BEARINGS REMOVAL & INSTALLATION

See Figures 3 and 4

If excessive camshaft wear is found, or if the engine is being completely rebuilt, the camshaft bearings should be replaced.

The front and rear bearings should be removed last, and installed first. Those bearings act as guides for the other bearings and pilot.

  1. Drive the camshaft rear plug from the block.
  2.  
  3. Assemble the removal puller with its shoulder on the bearing to be removed. Gradually tighten the puller nut until the bearing is removed.
  4.  
  5. Remove the remaining bearings, leaving the front and rear for last. To remove these, reverse the position of the puller, so as to pull the bearings towards the center of the block. Leave the tool in this position, pilot the new front and rear bearings on the installer, and pull them into position.
  6.  
  7. Return the puller to its original position and pull the remaining bearings into position.
  8.  

Ensure that the oil holes align when installing the bearings. This is very important! You can make a simple tool out of a piece of3/32in. brass rod to check alignment. See the illustration.

  1. Replace the camshaft rear plug, and stake it into position.
  2.  



Click image to see an enlarged view

Fig. Fig. 3: Camshaft bearing removal and installation tool



Click image to see an enlarged view

Fig. Fig. 4: Check cam bearing alignment with this homemade tool

 
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