REMOVAL & INSTALLATION
- Remove the grille. Remove the radiator hoses and remove the radiator.
- Remove the timing gear cover.
- Remove the valve cover and gasket, loosen all the rocker arm nuts, and pivot the rocker arms clear of the pushrods.
- Remove the distributor and the fuel pump.
- Remove the pushrods. Remove the coil and then remove the side cover. Remove the valve lifters.
- Remove the two camshaft thrust plate retaining screws by working through the holes in the camshaft gear.
- Remove the camshaft and gear assembly by pulling it out through the front of the block.
- If either the camshaft or the camshaft gear is being renewed, the gear must be pressed off the camshaft. The replacement parts must be assembled in the same way. When placing the gear on the camshaft, press the gear onto the shaft until it bottoms against the gear spacer ring. The end clearance of the thrust plate should be 0.001-0.005 in. (0.0254-0.127mm)
- Liberally coat the entire cam with assembly lube or equivalent, and then install the camshaft assembly in the engine. Be careful not to damage the bearings.
- Turn the crankshaft and the camshaft gears so that the timing marks align. Push the camshaft into position and install and torque the thrust plate bolts to 7 ft. lbs. (9 Nm)
- Check camshaft and crankshaft gear run-out with a dial indicator. Camshaft gear run-out should not exceed 0.004 in. (0.1016mm) and crankshaft gear run-out should not be above 0.003 in. (0.0762mm)
- Using a dial indicator, check the back-lash at several points between the camshaft and crankshaft gear teeth. Backlash should be 0.004-0.006 in. (0.1016-0.1524mm)
- Install the timing gear cover. Install the harmonic balancer.
- Install the valve lifters and the pushrods. Install the side cover. Install the coil and the fuel pump.
- Install the distributor and set the timing. Pivot the rocker arms over the pushrods and adjust the valves.
- Install the radiator, hoses and grille.
See Figures 1 and 2
- Complete steps 1 through 8 under Timing Chain, Cover Oil Seal, & Cover Removal and Installation, above. Skip steps 9 and 10, complete steps 11 through 15.
If equipped with air conditioning, unbolt the condenser and position it out of the way. If this is not possible, have a mechanic discharge the system. Never attempt to discharge the system yourself.
- Remove the hydraulic lifters, keeping them in order for installation.
- Slide the camshaft forward, out of the bearing bores. Do this carefully, to avoid damage to the bearing surfaces and bearings.
Slightly scored camshaft bearings will be satisfactory if the surfaces of camshaft journals are polished and bearings are cleaned up to remove burrs, and the fit of shaft in bearings is free and within the specification.
Should the bearing be galled beyond repair, the bearing will have to be replaced. Replacement camshaft bearings may be installed with Tool OTC 817, or equivalent. Care must be exercised during bearing removal and installation, not to damage bearings that are not being replaced.
- Remove the crankshaft.
- Assemble puller screw to required length.
- Select proper size expanding collect and back-up nut.
- Install expanding collet on expanding mandrel.
- Install back-up nut.
- Insert this assembly into camshaft bearing to be removed. Tighten back-up nut to expand collet to fit I.D. of bearing.
- Thread end of puller screw assembly into end of expanding mandrel and collet assembly.
- Install pulling plate, thrust bearing, and pulling nut on threaded end of puller screw.
- Bearing can then be removed by turning pulling nut.
Make certain to grip the5/8in. hex end of the puller screw with a wrench to keep it from rotating when the pulling nut is turned. Failure to do this will result in the locking up of all threads in the pulling assembly and possible over expansion of the collet.
- Repeat the above procedure to remove any other bearings, except the front bearing, which may be pulled from the rear of the engine.
When removing rear cam bearing, it is necessary to remove welch plug at the back of cam bore. However, if only the front bearing is being replaced it is not necessary to remove the engine or welch plug. The front bearing can be removed by using a spacer between the pulling plate and the cylinder block.To install:
- Assemble puller screw to required length.
- Select proper size expanding collet and back-up nut.
- Install expanding collet on expanding mandrel.
- Install back-up nut.
- Place new camshaft bearing on collet and GENTLY hand-tighten back-up nut to expand collet to fit bearing. Do not over tighten back-up nut. A loose sliding fit between collet and bearing surface is adequate. This will provide just enough clearance to allow for the collapse which will occur when the new bearing is pulled into the engine block.
- Slide mandrel assembly and bearing into bearing bore as far as it will go without force.
- Thread end of puller screw onto the end of the mandrel. Make certain to align oil holes in bearing and block properly. One of the collet separation lines may be used as a reference point.
- Install pulling plate, thrust bearing and pulling nut on threaded end of puller screw.
- Install all bearings in the same manner.
When installing rear cam bearing, install new welch plug at back of cam bore. Coat O.D. of plug with non-hardening sealer before installation.
- The remainder of the installation is the reverse of removal. Clean all gasket surfaces thoroughly and use new gaskets. Lubricate the camshaft lobes with heavy oil before installation, and be careful not to contact any of the bearings with the cam lobes. Make sure that the camshaft timing marks are aligned with the crankshaft marks. See installation steps under Timing Chain, Cover and Seal, Removal and Installation.
- Remove valve lifters as previously outlined.
- Remove crankcase from cover as previously outlined.
- Remove grille.
- Remove fuel pump pushrod.
- Complete camshaft removal as follows: Sprocket is a light fit on camshaft. If sprocket does not come off easily a light blow on the lower edge of the sprocket (with a plastic mallet) should dislodge the sprocket.
- Install two 5 / 16 in.-18 x 4 in. bolts in camshaft bolt holes then remove camshaft.
All camshaft journals are the same diameter and care must be used in removing camshaft to avoid damage to bearings.
The camshaft bearing journals should be measured with a micrometer for an out-of-round condition. If the journals exceed 0.001 in. (0.0254mm) out-of-round, the camshaft should be replaced. Camshaft bearings can be replaced while engine is disassembled for overhaul, or without complete disassembly of the engine. To replace bearings without complete disassembly remove the camshaft and crankshaft leaving cylinder heads attached and pistons in place. Before removing crankshaft, tape threads of connecting rod bolts to prevent damage to crankshaft. Fasten connecting rods against sides of engine so they will not be in the way while replacing camshaft bearings.
- With camshaft and crankshaft removed, drive camshaft rear plug from cylinder block.
- Using Tool Set J-98 or equivalent with nut and thrust washer installed to end of threads, index pilot in camshaft front bearing and install puller screw through pilot.
- Install remover and install tool with shoulder toward bearing, making sure a sufficient amount of threads are engaged.
- Using two wrenches, hold puller screw while turning nut. When bearing has been pulled from bore, remove the tool and bearing from puller screw.
- Remove remaining bearings (except front and rear) in the same manner. It will be necessary to index pilot in camshaft rear bearing to remove the rear intermediate bearing.
- Assemble remover and installer tool on driver handle and remove camshaft front and rear bearings by driving towards center of cylinder block.
The camshaft front and rear bearings should be installed first. These bearings will act as guides for the pilot and center the remaining bearings being pulled into place.
- Assemble remover and installer tool on driver handle and install camshaft front and rear bearings by driving towards center of cylinder block.
- Using Tool set J-98, with nut then thrust washer installed to end of threads, index pilot in camshaft front bearing and install puller screw through pilot.
- Index camshaft bearing in bore (with oil hole aligned as outlined below), then install remover and installer tool on puller screw with shoulder toward bearing.
Number one cam bearing oil hole must be positioned so that oil holes are equally distant from 6 o'clock position. Number two through number four bearing oil holes must be positioned at 5 o'clock position (toward left side of engine and at a position even with bottom of cylinder bore). Number five bearing oil hole must be in 12 o'clock position.
- Using two wrenches, hold puller screw while turning nut. After bearing has been pulled into bore, remove the remover and installer tool from puller screw and check alignment of oil hole in camshaft bearing.
- Install remaining bearings in the same manner. It will be necessary to index pilot in the camshaft rear bearing to install the rear intermediate bearing.
- Install a new camshaft rear plug.
Plug should be installed flush to 1 / 32 in. deep and be parallel with rear surface of cylinder block.
Whenever a new camshaft is installed coat camshaft lobes with Molykote®, or its equivalent. Also whenever a new camshaft is installed, replacement of all valve lifters is recommended to insure durability of the camshaft lobes and lifter feet.
- Lubricate camshaft journals with engine oil and install camshaft.
- Install timing chain on camshaft sprocket. Hold the sprocket vertically with the chain hanging down, and align marks on camshaft and crankshaft sprockets.
- Align dowel in camshaft with dowel hole in camshaft sprocket then install sprocket on camshaft.
- Draw the camshaft sprocket onto camshaft using the mounting bolts. Torque to specifications.
- Lubricate timing chain with engine oil.
- Install fuel pump pushrod.
- Install grille.
- Install crankcase front cover.
- Install valve lifters.
Consult the laws in your area before servicing the air conditioning system. In some states it is illegal to perform repairs involving refrigerant unless the work is done by a certified technician. R-12 refrigerant is a chlorofluorocarbon which, when released into the atmosphere, contributes to the depletion of the ozone layer in the upper atmosphere. Ozone filters out harmful radiation from the sun.
- Disconnect the battery.
- Drain and remove the radiator.
- Disconnect the fuel line at the fuel pump. Remove the pump on 1978 and later models.
- Disconnect the throttle cable and the air cleaner.
- Remove the alternator belt, loosen the alternator bolts, and move the alternator to one side.
- Remove the power steering pump from its brackets and move it out of the way.
- Remove the air conditioning compressor from its brackets and move the compressor out of the way without disconnecting the lines.
- Disconnect the hoses from the water pump.
- Disconnect the electrical and vacuum connections.
- Mark the distributor as to location in the block. Remove the distributor.
On 1977 and later models, remove the crankshaft pulley and the hub attaching bolt. Remove the crankshaft hub. Skip to Step 19.
- Raise the car and drain the oil pan.
- Remove the exhaust crossover pipe and starter motor.
- Disconnect the exhaust pipe at the manifold.
- Remove the harmonic balancer and pulley.
- Support the engine and remove the front motor mounts.
- Remove the flywheel inspection cover.
- Remove the engine oil pan.
- Support the engine by placing wooden blocks between the exhaust manifolds and the front crossmember.
- Remove the engine front cover.
- Remove the valve covers.
- Remove the intake manifold, oil filler pipe, and temperature sending switch.
- Mark the lifters, pushrods, and rocker arms as to location so that they may be installed in the same position. Remove these parts.
- If the car is equipped with air conditioning, discharge the A/C system and remove the condenser. See CAUTION above.
- Remove the fuel pump eccentric, camshaft gear, oil slinger, and timing chain.
- Carefully remove the camshaft from the engine.
The camshaft bearings must be replaced in complete sets. All bearings must be removed before any can be installed. No. 1 bearing must be removed first, then No. 2, then 3, 4, and 5. When installing the bearings, No. 5 must be installed first, then 4, 3, 2 and 1.
Camshaft Bearing Remover and Installer Set BT-6409 is an available tool. The set can be used to remove cam bearings with the engine either in or out of the car. To replace bearings with engine in car, proceed as follows:
- Install No. 1 Cam Bearing Remover and Installer BT-6409-1 on Handle J-8092 and drive out front cam bearing.
- Place Pilot BT-6409-6 on Driver BT-6409-7 and install No. 2 Cam Bearing Tool BT-6409-2 on driver and drive out No. 2 bearing.
- Remove No.3 and 4 bearings in the same manner, using BT-6409-3 and BT-6409-4 removers.
Each cam bearing is a different diameter and the correct sequence must be used for both removal and installation.
- To remove No. 5 bearing with engine in chassis, use puller BT-6409-8.
To aid aligning bearings with oil passages, place each bearing in the front bore with tapered edge toward block and align the oil hole in the bearing with the center of the oil slot in the bore. Mark top of bearing. When installing the bearings the mark will act as a guide.
- Place new No. 5 bearing on BT-6409-5 and drive bearing in until the last white line on the driver is flush with the front face of the pilot.
- Use BT-6409-9 to check oil hole opening.
- Remove BT-6409-5 Installer and install BT-6409-4. Place No. 4 bearing on installer and drive in until the next to last white line on driver is flush with pilot.
- Follow the same procedure to install No. 3 and No. 2.
- Install Tool BT - 6409-1 on Handle J-8092 and place No. 1 bearing on installer. Drive bearing in until white line on Installer BT - 6409 is flush with front face of block.
- Use BT-6409-9 to check all oil hole openings. Wire must enter hole or the bearing will not receive sufficient lubrication.
- Inspect the shaft for signs of excessive wear or damage.
- Liberally coat camshaft and bearings with heavy engine oil or engine assembly lubricant and insert the cam into the engine.
- Align the timing marks on the camshaft and crankshaft gears. See Timing Chain Replacement and Valve Timing for details.
- Install the distributor using the locating marks made during removal. If any problems are encountered, see Distributor Installation.
To install, reverse the removal procedure but pay attention to the following points:
- Install the timing indicator before installing the power steering pump bracket.
- Install the flywheel inspection cover after installing the starter.
- Replace the engine oil and radiator coolant.
Removal of the camshaft requires removal of the injection pump drive and driven gears, remove of the intake manifold, disassembly of the valve lifters, and re-timing of the injection pump.
The air conditioning, if equipped, must be discharged by a professional technician and the condenser removed.
- Disconnect the negative battery cables. Drain the coolant. Remove the radiator.
- Remove the intake manifold and gasket and the front and rear intake manifold seals. Refer to the intake manifold removal and installation procedure. Remove the oil pump drive assembly on the V6.
- Remove the balancer pulley and the balancer. See Caution under V8 diesel engine front cover removal and installation, above, for V8 engine. Remove the engine front cover using the appropriate procedure. Rotate the engine so that the timing marks align on V6's.
- 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.
- On V8's, if equipped with air conditioning, the condenser must be discharged and removed from the car.
R-12 refrigerant is a chlorofluorocarbon which, when released into the atmosphere, contributes to the depletion of the ozone layer in the upper atmosphere. Ozone filters out harmful radiation from the sun.
Consult the laws in your area before servicing the air conditioning system. In some states it is illegal to perform repairs involving refrigerant unless the work is done by a certified technician.
- Remove the camshaft sprocket retaining bolt, and remove the timing chain and sprockets, using the procedure outlined earlier.
- On V6's, remove the front camshaft bearing retainer bolt and the retainer, then remove the camshaft sprocket key and the injection pump drive gear.
- Position the camshaft dowel pin at the 3 o'clock position on the V8.
- On V8's, 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.
- To remove the fuel injection pump driven gear, remove the injection pump intermediate pump adapter (V6's) and the pump adapter (All), remove the snapring, and remove the selective washer. Remove the driven gear and spring.
- 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.
- If either the injection pump drive or driven gears are to be replaced, replace both gears. make certain the marks (0) are in alignment on both gears before inserting the cam gear key on the V6.
- Coat the camshaft and the cam bearings with GM lubricant No. 1052365 or the equivalent.
- Carefully slide the camshaft into position in the engine.
- 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.
- Install the injection pump driven gear, spring, shim, and snapring. Check the gear end-play. If the end-play is not within 0.002 in. to 0.006 in. on V8's through 1979 and V6's, and 0.002 in. to 0.015 in. in 1980 and later V8's, replace the shim to obtain the specified clearance. Shims are available in 0.003 in. increments, from 0.080 in. to 0.115 in.
- On V8's 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. On the V6, align the zero marks on the injection pump drive and driven gears, then install the camshaft sprocket key. Install the camshaft bearing retainer.
- Install the timing chain and sprockets, making sure the timing marks are aligned.
- 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.
- Install the injection pump adapter and injection pump. See the appropriate sections under Fuel System in Section 4 for procedures.
- Install the remaining components in the reverse order of removal.
MEASURING LOBE LIFT
- With the rocker arms removed, position indicator with ball socket adapter (Tool J-8520) on pushrod. Make sure pushrod is in the lifter socket.
- Rotate the crankshaft slowly in the direction of rotation until the lifter is on the heel of the cam lobe. At this point, the pushrod will be in its lowest position.
- Set dial indicator on zero, then rotate the crankshaft slowly, or attach an auxiliary starter switch and bump the engine over, until the pushrod is in fully raised position.
- Compare the total lift recorded from the dial indicator with specifications.
- If camshaft readings for all lobes are within specifications, remove dial indicator assembly.
- Install and adjust valve mechanism as outlined.