GM Cutlass RWD 1970-1987 Repair Guide

Timing Chain Cover and Seal

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REMOVAL & INSTALLATION



See Figures 1, 2, 3, 4, 5, 6 and 7

L6 Engine

Align engine to No. 1 cylinder at TDC before cam gear installation. The L6 engine camshaft is gear-driven. The removal of the timing gear requires removal of the camshaft. After the camshaft is removed, place the camshaft and gear in an arbor press and remove the gear from the cam. Installation is in the reverse order of removal. The clearance between the camshaft and the thrust plate should be 0.001-0.005 in. (0.0254mm-0.127mm) Refer to camshaft removal and installation section.

  1. Drain the engine coolant, remove the radiator hoses, and remove the radiator.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the fan belt and any accessory belts. Remove the fan pulley.
  2.  
  3. A harmonic balancer puller is necessary to pull the balancer. Install the puller and remove the balancer.
  4.  
  5. Remove the two screws which attach the oil pan to the front cover. Remove the screws which attach the front cover to the block. Do not remove the cover yet.
  6.  
  7. Before the front cover is removed, it is necessary to cut the oil pan front seal. Pull the cover forward slightly.
  8.  
  9. Using a sharp knife or razor knife, cut the oil pan front seal flush with the cylinder block on both sides of the cover.
  10.  
  11. Remove the front cover and the attached portion of oil pan front seal. Remove the front cover gasket from the block.
  12.  



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Fig. Fig. 1: Remove the timing chain cover bolts



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Fig. Fig. 2: Remove the timing chain cover



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Fig. Fig. 3: Clean both mating surfaces thoroughly

To install:
  1. Install the front cover, first obtain an oil pan front seal. Cut the tabs from the new seal.
  2.  
  3. Install the seal in the front cover, pressing the tops into the holes provided in the cover. Coat the mating area of the front cover with a room temperature vulcanizing sealer first.
  4.  
  5. Coat the new front cover gasket with sealer and install it on the cover.
  6.  
  7. Apply a bead of RTV sealer to the joint formed at the oil pan and cylinder block.
  8.  
  9. Install the front cover.
  10.  
  11. Install the harmonic balancer. Make sure the front cover seal is positioned evenly around the balancer. Make sure the balancer goes on evenly.
  12.  
  13. Install the fan pulley and any accessory belts
  14.  
  15. Install the radiator and hoses
  16.  
  17. Refill the radiator with coolant.
  18.  



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Fig. Fig. 4: 6-250 timing gear alignment

Buick Built Engines
  1. Drain the cooling system.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the radiator, fan, pulley and belt.
  2.  
  3. Remove the fuel pump and alternator, if necessary to remove cover.
  4.  
  5. Remove the distributor. If the timing chain and sprockets will not be disturbed, note the position of the distributor for installation in the same position.
  6.  
  7. Remove the thermostat bypass hose.
  8.  
  9. Remove the harmonic balancer.
  10.  
  11. Remove the timing chain-to-crankcase bolts.
  12.  
  13. Remove the oil pan-to-timing chain cover bolts and remove the timing chain cover.
  14.  
  15. Using a punch, drive out the old seal and the shedder toward the rear of the seal.
  16.  
  17. Coil the new packing around the opening so the ends are at the top. Drive in the shedder using a punch. Properly size the packing by rotating a hammer handle around the packing until the balancer hub can be inserted through the opening.
  18.  
  19. Align the timing marks on the sprockets.
  20.  
  21. Remove the camshaft sprocket bolt without changing the position of the sprocket. Remove the oil pan.
  22.  
  23. Remove the front crankshaft oil slinger.
  24.  



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Fig. Fig. 5: Remove the crankshaft oil slinger

  1. Remove the camshaft sprocket bolts.
  2.  
  3. Using the two large screwdrivers, carefully pry the camshaft sprocket and the crankshaft sprocket forward until they are free. Remove the sprockets and the chain.
  4.  

To install:
  1. Make sure, with sprockets temporarily installed, that No. 1 piston is at top dead center and the camshaft sprocket O-mark is straight down on the centerline of both shafts.
  2.  
  3. Remove the camshaft sprocket and assemble the timing chain on both sprockets. Then slide the sprockets-and-chain assembly on the shafts with the O-marks in their closest together position and on a centerline with the sprocket hubs.
  4.  
  5. Assemble the slinger on the crankshaft with I.D. against the sprocket, (concave side toward the front of engine). Install the oil pan, if removed.
  6.  



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Fig. Fig. 6: Timing chain cover - Buick built engines

  1. Install the camshaft sprocket bolts.
  2.  
  3. Install the distributor drive gear.
  4.  
  5. Install the drive gear and eccentric bolt and retaining washer. Torque to 40-55 ft. lbs. (54-74 Nm)
  6.  
  7. Install the timing case cover. Install a new seal by lightly tapping it in place. The lip of the seal faces inward. Pay particular attention to the following points.
    1. Remove the oil pump cover and pack the space around the oil pump gears completely full of petroleum jelly. There must be no air space left inside the pump. Reinstall the pump cover using a new gasket.
    2.  
    3. The gasket surface of the block and timing chain cover must be clean and smooth. Use a new gasket correctly positioned.
    4.  
    5. Install the chain cover being certain the dowel pins engage the dowel pin holes before starting the attaching bolts.
    6.  
    7. Lube the bolt threads before installation and install them.
    8.  
    9. If the car has power steering the front pump bracket should be installed at this time.
    10.  
    11. Lube the O.D. of the harmonic balancer hub before installation to prevent damage to the seal when starting the engine.
    12.  

  8.  



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Fig. Fig. 7: Valve timing marks - Buick built engines

V8 Chevrolet Built Engines

See Figures 8 and 9

If the timing chain is to be replaced, position the engine to align the timing marks at TDC (0 on the scale) with the No. 1 cylinder on its compression stroke (valves closed). DO NOT rotate the cam or crankshaft while the chain is removed.

  1. Drain and remove radiator.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the fan belt and accessory drive belts. Remove the crankshaft pulley.
  2.  
  3. Remove harmonic balancer, using a puller.
  4.  

The outer ring (weight) of the harmonic balancer is bonded to the hub with rubber. The balancer must be removed with a puller which acts on the inner hub only. Pulling on the outer portion of the balancer will break the rubber bond or destroy the tuning of the torsional damper.

  1. Remove the water pump. If the oil pan isn't to be removed, cut the pan seal off flush with the block.
  2.  
  3. Remove timing gear cover attaching screws, and cover and bracket.
  4.  

To install:
  1. Clean all the gasket mounting surfaces.
  2.  
  3. Apply a bead of silicone sealer to the oil pan-to-cylinder block joint.
  4.  
  5. Install a centering tool in the crankshaft snout hole in the front cover and install the cover.
  6.  



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Fig. Fig. 8: Valve timing marks - Chevrolet built engines



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Fig. Fig. 9: It is not necessary on the Chevrolet built engines to remove or lower the pan to remove the timing cover. The seal retainer is shortened enough to clear the pan

  1. Install the front cover bolts finger-tight, remove the centering tool and tighten the cover bolts. Install the harmonic balancer, pulley, water pump, belts, radiator, and all other parts.
  2.  


CAUTION
The engines use a harmonic balancer. Breakage may occur if the balancer is hammered back onto the crankshaft. A special installation tool is necessary.

When replacing the crankshaft damper, it has been found that lightly polishing the crankshaft damper with crocus cloth will greatly ease replacement. This procedure will also assist in any future removals, as it is sometimes difficult to pull a damper even with a puller. Be sure that the polishing is not overdone, or the damper will wobble on the crankshaft.

V8 Oldsmobile Built Gasoline Engines

See Figures 10, 11, 12 and 13

  1. Disconnect the negative battery cable.Drain the coolant. Disconnect the radiator hose and the bypass hose. Remove the fan, belts and pulley.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the vibration damper and crankshaft pulley.
  2.  
  3. Drain the oil and remove the oil pan.
  4.  
  5. Remove the front cover attaching bolts and remove the cover, timing indicator and water pump from the front of the engine.
  6.  
  7. On 1977 and later models, grind a chamfer on the end of each dowel pin as illustrated. When install the dowel pins, they must be inserted chamfered end first. Trim about 1 / 8 in.(3.1mm) from each end of the new front pan seal and trim any excess material from the front edge of the oil pan gasket. Be sure all mating surfaces are clean.
  8.  
  9. On 1975-76 models apply a sealer around water holes on the new cover gasket before applying it to the block.
  10.  



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Fig. Fig. 10: Chamfer on the dowel pins - Oldsmobile built engines



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Fig. Fig. 11: Remove the balancer - Oldsmobile built V8 engines



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Fig. Fig. 12: Trimming the oil pan seals - Oldsmobile built engines

  1. On 1977 and later models:
    1. Clean all seal mating surfaces with solvent.
    2.  
    3. When installing the new front cover gasket, first apply sealer to the water pump bolt hole areas of the seal and then position the gasket to the block.
    4.  
    5. Apply RTV sealer to the junction of block, pan, and front cover.
    6.  
    7. In positioning the front cover onto the block and gasket, press it downward to compress the seal. Then, rotate the cover left and right while you guide the pan seal into the cavity with a small prybar, as shown. Now, apply oil to the threads and install two of the bolts finger-tight to hold the cover in place. Install the two dowel pins, chamfered end first.
    8.  

  2.  
  3. To install, note these points:
    1. When installing cover bolts, first coat them with engine oil. Tighten evenly, torquing the four lower bolts to 35 ft. lbs. (48 Nm) and the four bolts passing through the water pump to 22 ft. lbs. (30 Nm).
    2.  
    3. Apply a high quality lubricant (an example is GM 1050169) to the sealing surface of the balancer.
    4.  
    5. When installing the balancer bolt, torque to proper specifications. Crankshaft pulley attaching bolts are torqued to 10 ft. lbs. (14 Nm); fan pulley attaching bolts are torqued to 20 ft. lbs. (27 Nm).
    6.  

  4.  



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Fig. Fig. 13: Applying sealer and trimming the pan gasket - Oldsmobile built engines

263 and 350 Oldsmobile Built Diesel Engines

See Figures 14 and 15

  1. Disconnect the negative battery cable.Drain the cooling system and disconnect the radiator hoses.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.



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Fig. Fig. 14: Engine front cover and timing chain assembly - 263 Oldsmobile built diesel engine



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Fig. Fig. 15: Installing the front cover - Oldsmobile built engines

  1. Remove all belts, fan and pulley, crankshaft pulley and balancer, using a balancer puller.
  2.  


CAUTION
The use of any other type of puller, such as a universal claw type which pulls on the outside of the hub, can destroy the balancer. The outside ring of the balancer is bonded in rubber to the hub. Pulling on the outside will break the bond. The timing mark is on the outside ring. If it is suspected that the bond is broken, check that the center of the keyway is 16 degrees from the center of the timing slot. In addition, there are chiseled aligning marks between the weight and the hub.

  1. Unbolt and remove the cover, timing indicator and water pump.
  2.  
  3. It may be necessary to grind a flat on the cover for gripping purposes
  4.  

To install:
  1. Grind a chamfer on one end of each dowel pin.
  2.  
  3. Cut the excess material from the front end of the oil pan gasket on each side of the block.
  4.  
  5. Clean the block, oil pan and front cover mating surfaces with solvent.
  6.  
  7. Trim about 1 / 8 in. (3.1mm) off each end of a new front pan seal.
  8.  
  9. Install a new front cover gasket on the block and a new seal in the front cover.
  10.  
  11. Apply sealer to the gasket around the coolant holes.
  12.  
  13. Apply sealer to the block at the junction of the pan and front cover. On V6, apply R.T.V. sealer on the front cover oil pan seal retainer.
  14.  
  15. Place the cover on the block and press down to compress the seal. Rotate the cover left and right and guide the pan seal into the cavity using a small screwdriver. Oil bolt threads and heads, install two to hold the cover in place, then install both dowels pins (chamfered end first). Install remaining front cover bolts.
  16.  
  17. Apply a lubricant, compatible with rubber, on the balancer seal surface.
  18.  
  19. Install the balancer and bolt. Torque the bolt to 200-300 ft. lbs. (271-406 Nm) on V8, 160-350 ft. lbs. (219-474 Nm) on V6.
  20.  
  21. Install the belts, connect the negative battery cable, refill the engine with coolant, start the engine and check for leaks.
  22.  

 
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