GM Corvette 1984-1996 Repair Guide

Camshaft, Bearings and Lifters

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REMOVAL & INSTALLATION



5.7L (VIN 8) Engine

See Figure 1

  1. Take the vehicle to a reputable repair shop and have the A/C system properly discharged and recovered, using the proper tools.
  2.  
  3. Disconnect the negative battery cable. Drain the engine cooling system into a suitable container.
  4.  
  5. Remove the air cleaner assembly
  6.  
  7. Remove the radiator, as outlined in this section.
  8.  
  9. Remove the A/C condenser, as follows:
    1. Unbolt the accumulator attaching screw(s), then reposition the accumulator away from the condenser,
    2.  
    3. Remove the accumulator bracket.
    4.  
    5. Disconnect the accumulator hose and compressor hose from the condenser, then cap or plug the hoses and openings immediately to prevent contaminating the A/C system.
    6.  
    7. Remove the condenser from the vehicle.
    8.  

  10.  
  11. Remove the intake manifold from the vehicle.
  12.  
  13. Remove the rocker arm covers, then remove the rocker arms.
  14.  
  15. Remove the valve lifters, and place them in a rack, so they may installed in the proper position. The lifters must be installed in the same bores as they were removed from.
  16.  
  17. Remove the timing chain.
  18.  
  19. Remove the camshaft assembly, as follows:
    1. Install three 5/16-18 x 4-inch bolts in the camshaft bolt holes.
    2.  
    3. Carefully rotate and pull the camshaft assembly out of the bearings.
    4.  

  20.  



Click image to see an enlarged view

Fig. Fig. 1: Carefully pull the camshaft out, using the bolts threaded into the camshaft

  1. Inspect the bearings for scratches, pits or loose fit. If necessary, remove the camshaft bearings as follows:
    1. Drive the camshaft rear plug from the cylinder block.
    2.  
    3. Using tool J 6098-01, or equivalent camshaft bearing removal and installation tool, with the nut and thrust washer installed to the end of the threads, index the pilot in the camshaft front bearing and install the puller screw through the pilot.
    4.  
    5. Install the tool with the shoulder toward the bewaring, making sure enough there are enough threads engaged.
    6.  
    7. Using 2 wrenches, hold the puller screw while turning the nut. When the bearing has been pulled from the bore, remove the tool and bearing from the puller screw.
    8.  
    9. Remove the remaining bearings (except front and rear) using the same procedure. It will be necessary to index the pilot in the camshaft rear bearing to remove the rear intermediate bearing.
    10.  
    11. Assemble the tool on the driver handle and remove the camshaft front and rear bearings by driving towards the center of the cylinder block.
    12.  

  2.  

To install:
  1. Install new camshaft bearings, as follows:
  2.  

The front and rear bearings should be installed first. They will act as guide for t he pilot, and center the remaining bearings being pulled into place.

  1. Assemble the removal and installation tool on the driver handle, then install the camshaft front and rear bearings by driving toward the center of the cylinder block.
  2.  
  3. Using the camshaft bearing removal and installation tool set, with the nut and thrust washer installed to each end of the threads, index the pilot in the camshaft front bearing and install the puller screw through the pilot.
  4.  
  5. Index the camshaft bearing in the bore (with the oil hole aligned as outlined later), then install the removal and installation tool on the puller screw with the should toward the bearing.

    The No. 1 cam bearing oil hole must be positioned so that the oil holes are at the 1 and 5 oclock positions.
     
    The No. 2-4 bearing oil holes must be positioned at the 5 oclock position (toward the left side of the engine and at a position even with the bottom of the cylinder bore).
     
    The No. 5 bearing oil hole must be in the 12 oclock position.
     

  6.  
  7. Using 2 wrenches, hold the puller screw while turning the nut. After the bearing has been pulled into the bore, remove the tool from the screw and check alignment of the oil hole in the camshaft bearing.
  8.  
  9. Install the remaining bearings in the same manner. It will be necessary to index the pilot in the camshaft rear bearing to install the rear intermediate bearing.
  10.  
  11. Coat a new camshaft rear plug outside diameter with sealant, then install flush to 0.031 in. (0.8mm) depth.
  12.  

When a new camshaft is installed, install a new oil filter and new oil.

  1. When installing a new camshaft assembly, coat the camshaft lobes with "Molykote" or equivalent. When installing a new camshaft, replace all valve lifters to ensure durability of the camshaft lobes and lifter rollers.
  2.  
  3. Lubricate all camshaft journals with engine oil, then carefully install the camshaft assembly.
  4.  
  5. Install the timing chain.
  6.  
  7. Coat the lifters with a suitable prelube, then install them in the same positions as they were removed from.
  8.  
  9. Install the rocker arms and covers.
  10.  
  11. Install the intake manifold.
  12.  
  13. Install the condenser as follows:
    1. Position the condenser in the vehicle.
    2.  
    3. Unplug or uncap the accumulator and condenser hoses, then connect the hoses to the condenser.
    4.  
    5. Install the accumulator bracket, then place the accumulator in position and install the attaching screw(s).
    6.  

  14.  
  15. Install the radiator and the air cleaner assembly.
  16.  
  17. Fill the cooling system with the proper type and amount of coolant.
  18.  
  19. Connect the negative battery cable.
  20.  
  21. Take the vehicle to a reputable repair shop to have the A/C system properly evacuated and charged.
  22.  

5.7L (VIN J) Engine

See Figures 2 and 3

The VIN J engine utilizes 4 overhead camshafts. Certain shafts will have identifying bands between the first journal and lobe to distinguish between the right and left, intake and exhaust camshafts. The right intake has 1 flat band. The right exhaust has 1 raised band. The left intake has 1 flat and 1 raised band. The left exhaust has 2 raised bands.

  1. If removing the left bank camshafts, take the vehicle to a reputable repair shop and have the A/C system properly discharged and recovered, using the proper tools.
  2.  
  3. Disconnect battery negative cable and drain the engine coolant into a suitable container.
  4.  
  5. To gain access to the right camshafts, remove the oil filter housing and right camshaft cover as follows:
    1. Remove the air intake duct.
    2.  
    3. Remove the hoses and clamps from the coolant outlets, radiator inlet and inlet pipe.
    4.  
    5. Remove the hoses and inlet pipe assembly from the vehicle.
    6.  
    7. Remove the water pump pulley.
    8.  
    9. Release the belt tensioner and remove the serpentine belt.
    10.  
    11. Remove the retaining bolt and the belt tensioner from the engine.
    12.  
    13. Remove the oil filter.
    14.  
    15. Disengage the electrical connectors from the oil pressure sensor, oil temperature sensor and the low oil pressure switch.
    16.  
    17. Remove the oil pressure sensor from the oil filter housing.
    18.  
    19. Remove the alternator bracket from the oil filter housing.
    20.  
    21. Disconnect and plug the oil cooler lines from the filter housing.
    22.  
    23. Remove the oil filter housing mounting bolts and remove the assembly.
    24.  

  6.  

If equipped with a 1 piece front cover/oil filter housing gasket, cut the old gasket along the front cover.

    1. Remove spark plug wires from plugs in the right cylinder head.
    2.  
    3. Disengage the electrical connector from the blower motor resistor block.
    4.  
    5. Remove the screws attaching the evaporator housing quarter panel, then remove the panel.
    6.  
    7. Remove the bolts attaching the coolant outlet pipe bracket to the alternator bracket and the coolant outlet to the injector housing, then position aside.
    8.  
    9. For 1993-95 vehicles, remove the upper EGR pipe bolts and pipe.
    10.  
    11. Remove the bolt attaching the fresh air pipe bracket to the injector housing.
    12.  
    13. Remove the camshaft cover attaching bolts and the camshaft cover.
    14.  


  1. To gain access to the left camshafts, remove the air conditioning compressor and left valve cover as follows:
    1. Remove the throttle body assembly and the serpentine drive belt.
    2.  
    3. Remove the engine oil temperature sensor.
    4.  
    5. Remove the alternator assembly.
    6.  
    7. Remove the refrigerant hose from the A/C compressor, then immediately cap or plug the openings to prevent system contamination and damage.
    8.  
    9. Remove the compressor mounting bolts and electrical connection.
    10.  
    11. Remove the compressor from the vehicle.
    12.  
    13. Remove the power steering pump from the engine.
    14.  
    15. Remove the spark plug wires from the plugs in the left cylinder head.
    16.  
    17. Remove the ventilation breather pipe from the camshaft cover.
    18.  
    19. Remove the throttle and cruise control cable or control cable hold-down clamps from the plenum.
    20.  
    21. If not done already, remove the throttle body extension and coolant outlet pipe.
    22.  
    23. Remove the vacuum hose from the power brake booster and, if necessary, remove the booster assembly.
    24.  
    25. Remove the left camshaft cover attaching bolts and remove the cover.
    26.  

  2.  
  3. Raise and support the vehicle safely.
  4.  
  5. Disengage the electrical connector from the crankshaft ignition timing sensor.
  6.  
  7. Remove the ignition timing sensor from the cylinder case.
  8.  
  9. Install the crankshaft timing slot locator tool J-38098 or equivalent, into the ignition timing sensor opening. Make sure the tool head is fully seated with the indicating pin inserted into the deep notch of the crankshaft timing disc.
  10.  
  11. Lower vehicle.
  12.  
  13. Remove the bolts attaching the secondary timing chain tensioner housing to the cylinder head, then remove the housing, O-ring and tensioner from the cylinder case.
  14.  
  15. Remove the bolts and washers attaching the camshaft to the sprockets.
  16.  

Install a wrench on the rear camshaft hex when removing the sprocket bolts, to prevent the camshafts from exerting force on the crankshaft timing slot locator tool.

  1. Remove the camshaft timing plates and pins.
  2.  
  3. Remove the camshaft retainers and thrust washers.
  4.  
  5. Remove the camshafts and sprockets from the vehicle. Install timing chain retainers J-38099 or equivalent, to retain secondary chain loops.
  6.  
  7. Remove lifters from bores and inspect. Make sure any lifters, to be reused, are retained in proper order so each one can be returned to its original bore.
  8.  



Click image to see an enlarged view

Fig. Fig. 2: View of 2 of the 4 camshafts used on the 5.7L (VIN J) engine



Click image to see an enlarged view

Fig. Fig. 3: Valve lifters MUST be install in the same bore as they were removed from

To install:
  1. Inspect the camshaft bearing journals for wear or damage.
  2.  
  3. Inspect the camshaft bearing surfaces in the cylinder head and camshaft cover for wear or damage.
  4.  

The camshaft cover and cylinder head must be replaced as a set if excessive wear or damage to the bearing surfaces is found.

  1. Install the each camshaft and lifter assembly, 1 at a time:
    1. Lubricate lifters and bores with clean engine oil, then install lifters into bores. If a camshaft is replaced, new lifters must also be used.
    2.  
    3. Install the camshaft sprocket onto the secondary timing chain, while removing the timing chain retainer.
    4.  
    5. Slide the camshaft into the sprocket, noting the position of the alignment hole for timing pin tool installation. Position the camshaft in the neutral position, no valves opened.
    6.  
    7. Lubricate camshaft journals, lobes, thrust washers and retainers with clean engine oil.
    8.  
    9. Install the camshaft thrust washers, retainers and bolts. Torque bolts to 89 inch lbs. (10 Nm).
    10.  
    11. Repeat Steps a-e for the remaining camshafts.
    12.  

  2.  
  3. Install timing pins J-37326 into camshaft retainers and the indexing holes in the camshafts. Camshafts can be rotated using the cast hex at the camshaft rear.
  4.  
  5. Install the camshaft secondary chain pre-tensioner, J-37305 or equivalent. Hand-tighten to remove slack from the timing chain, but do not overtighten.
  6.  
  7. Install timing plates, pins and washers. If no holes line up on the timing plate, reverse the plate.
  8.  
  9. Apply Loctite® 262 or equivalent, on the NEW camshaft sprocket bolts, then install and finger-tighten the bolts. New camshaft bolts should be used each time the camshaft is removed. Tighten the bolts to 18 ft. lbs. (25 Nm) and turn 80-85 degrees using a torque angle meter. A backup wrench should be used on the rear camshaft hex to prevent damaging the timing pins.
  10.  
  11. Remove timing pins J-37326.
  12.  
  13. Remove the secondary timing chain pre-tensioner tool and install the new secondary timing chain tensioner, housing, new O-ring and bolts. Lubricate tensioner with engine oil. Make sure the oil hole in the tensioner piston be installed in a vertical position and that the fork on the end of the tensioner is properly engaged onto the chain guide. After installing, use a blunt punch to release the plunger. Torque chain tensioner bolts to 89 inch lbs. (10 Nm).
  14.  
  15. Raise and support the vehicle safely.
  16.  
  17. Remove crankshaft timing slot locator J-38098 from the cylinder case.
  18.  
  19. Install the crankshaft position sensor into the cylinder case and tighten the retainer(s) to 71 inch lbs. (8 Nm).
  20.  
  21. Engage the timing sensor electrical connector and lower the vehicle.
  22.  
  23. Apply Permabond® A136 or equivalent, to the camshaft covers and Loctite® 565 or equivalent, to the end plugs. Install the end plugs and new spark plug bore O-rings prior to cover installation.
  24.  
  25. Install the camshaft covers in the reverse order of removal. The camshaft cover retainers must be tightened in the proper sequence in order to assure proper camshaft operation. Tighten the M8 bolts to 15 ft. lbs. (20 Nm), repeat 3 times. Tighten the M6 screws to 89 inch lbs. (10 Nm). Also, be sure to install a new coolant outlet cover gasket and tighten the cover screws to 89 inch lbs. (10 Nm).
  26.  
  27. For the right bank camshafts, install oil filter housing assembly.
  28.  
  29. For the left bank camshafts, install the air conditioning compressor assembly.
  30.  
  31. Reconnect the negative battery cable and properly fill the engine cooling system.
  32.  
  33. If the left bank camshafts were removed, take the vehicle to a reputable repair shop to have the A/C system properly evacuated and charged.
  34.  

5.7L (VIN P and 5) Engines

See Figure 4

  1. Disconnect the negative battery cable and remove the air cleaner assembly.
  2.  
  3. Remove the timing chain front cover.
  4.  
  5. Remove the intake manifold.
  6.  
  7. Remove the retaining bolt and lift the oil pump driveshaft assembly from the rear of the lifter valley.
  8.  
  9. Remove the rocker arm and pushrod assemblies.
  10.  
  11. Remove the camshaft sprocket from the engine.
  12.  
  13. Remove the valve lifters.
  14.  
  15. Remove the high fill reservoir hose from the radiator.
  16.  
  17. Remove the relay bracket from the left side of the radiator support.
  18.  
  19. Remove the AIR pump intake duct and bolts, then reposition the AIR pump.
  20.  
  21. Remove the retaining nuts and screws, then remove the upper radiator support.
  22.  
  23. Remove the radiator.
  24.  
  25. Raise and support the vehicle safely.
  26.  
  27. Unplug the cooling fan electrical connector.
  28.  
  29. Remove the lower fan shroud bolts and lower the vehicle.
  30.  
  31. Remove the fan shroud and fan assembly.
  32.  
  33. Disconnect the A/C condenser line bracket at the front crossmember.
  34.  
  35. Raise the front of the engine with a suitable lifting device.
  36.  

When raising and supporting the engine, NEVER place a jack under the oil pan, crankshaft pulley or any sheetmetal. There is a minimal clearance between the oil pan and the pump screen. Jacking against the pan could cause sufficient deformation to damage the oil pickup unit.

  1. Remove the camshaft retainer bolts and retainer.
  2.  
  3. Install three 5 / 16 -18 x 4 inch bolts into the camshaft bolt holes.
  4.  
  5. Using the bolts, carefully rotate the camshaft and pull from the bearings. All camshaft journals are the same diameter so care must be used to avoid damaging the bearings. Remove the camshaft from the vehicle.
  6.  



Click image to see an enlarged view

Fig. Fig. 4: Thread screws into the end of the camshaft and carefully pull it straight out of the block-5.7L (VIN P and 5) engines

To install:
  1. Inspect the camshaft and bearings, replace as necessary.
  2.  
  3. If installing a new camshaft, coat the lobes with Molykote® or equivalent pre-lube and be sure to replace all lifters to assure camshaft durability.
  4.  
  5. Lubricate all camshaft journals with clean engine oil and carefully insert the camshaft into the engine block.
  6.  
  7. Install the camshaft retainer and tighten the bolts to 108 inch lbs. (12 Nm).
  8.  
  9. Lower the front of the engine and connect the A/C condenser line bracket to the front crossmember.
  10.  
  11. Install the fan and shroud assembly.
  12.  
  13. Raise and support the vehicle safely, then install the lower fan shroud bolts.
  14.  
  15. Engage the cooling fan electrical connections and lower the vehicle.
  16.  
  17. Install the radiator, followed by the upper radiator support, nuts and screws.
  18.  
  19. Install the AIR pump, bolts and intake duct.
  20.  
  21. Install the relay bracket to the left side of the radiator support.
  22.  
  23. Connect the high fill reservoir hose to the radiator.
  24.  
  25. Install the valve lifters.
  26.  
  27. Install the camshaft sprocket.
  28.  
  29. Install the valve rocker arm and pushrod assemblies.
  30.  
  31. Install the oil pump driveshaft assembly and bolt. Tighten the bolt to 13 ft. lbs. (18 Nm).
  32.  
  33. Install the intake manifold.
  34.  
  35. Install the timing chain front cover.
  36.  
  37. Install the air cleaner assembly and connect the negative battery cable.
  38.  

INSPECTION



Camshaft Lobe Lift

Check the lift of each lobe in consecutive order and make a note of the reading.

  1. Remove the fresh air inlet tube and the air cleaner. Remove the heater hose and crankcase ventilation hoses. Remove valve rocker arm cover(s).
  2.  
  3. Remove the rocker arm stud nut or fulcrum bolts, fulcrum seat and rocker arm.
  4.  
  5. Make sure the pushrod is in the valve tappet socket. Install a dial indicator so that the actuating point of the indicator is in the pushrod socket (or the indicator ball socket adapter tool is on the end of the pushrod) and in the same plane as the pushrod movement.
  6.  
  7. Disable the ignition and fuel systems.
  8.  
  9. Install a remote starter switch. Crank the engine with the ignition and fuel system disabled. Turn the crankshaft over until the tappet is on the base circle of the camshaft lobe. At this position, the pushrod will be in its lowest position.
  10.  
  11. Zero the dial indicator. Continue to rotate the crankshaft slowly until the pushrod is in the fully raised position.
  12.  
  13. Compare the total lift recorded on the dial indicator with the specification shown on the specification charts in this section.
  14.  

To check the accuracy of the original indicator reading, continue to rotate the crankshaft until the indicator reads zero. If the lift on any lobe is below specified wear limits listed, the camshaft and the valve tappet operating on the worn lobe(s) must be replaced.

  1. Install the rocker arm, fulcrum seat and stud nut or fulcrum bolts. Adjust the valves, if required (refer to the valves procedure in this section).
  2.  
  3. Install the valve rocker arm cover(s) and the air cleaner.
  4.  

Camshaft End Play

On all gasoline V8 engines, prying against the aluminum-nylon camshaft sprocket, with the valve train load on the camshaft, can break or damage the sprocket. Therefore, the rocker arm adjusting nuts must be backed off, or the rocker arm and shaft assembly must be loosened sufficiently to free the camshaft. After checking the camshaft end play, check the valve clearance. Adjust if required (refer to procedure in this section).

  1. Push the camshaft toward the rear of the engine. Install a dial indicator or equivalent so that the indicator point is on the camshaft sprocket attaching screw.
  2.  
  3. Zero the dial indicator. Position a prybar between the camshaft gear and the block. Pull the camshaft forward and release it. Compare the dial indicator reading with the specifications.
  4.  
  5. If the end play is excessive, check the spacer for correct installation before it is removed. If the spacer is correctly installed, replace the thrust plate.
  6.  
  7. Remove the dial indicator.
  8.  

 
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