Valve Gear

Valve gear
Removal of the valve gear
This method presupposes that the cylinder head has been removed.

IMPORTANT: The cylindrical surfaces surrounding the valve springs are sliding surfaces for the tappets. These surfaces must not be scored. Therefore, protect the tappet guides with protective collars 83 93 746.





1 Remove the camshaft bearing caps. It is important to finish with the bearing cap on the tappets that are under load. Lift out the camshafts.
2 Remove the tappets and keep them in the Valve stand 83 93 787.





3 Fit protective collars 83 93 746.
4 Use 41 valve spring comoressor83 93 761 and Valve Spring deoressor83 93 779 to remove the valve cones.





5 Lift out the valve discs and valve springs. Lift out the washer with guide seals with THC pliers for removing valve guide seals 8394157.
6 Remove the valves. Keep them in Valve stand 83 93 787.

Fitting the valve gear

IMPORTANT: Defective valve stem seals must be replaced. The sealing surfaces and bearings must be lubricated with oil before the valves are fitted. Make sure that the cylinder head rests on blocks to prevent damage to the valves (bent valve stems) when the camshafts are turned.





1 Fit the washer with valve stem seal using Pliers for removing valve guide seaB3 94 157.
2 Fit the valves and springs.





3 Use valve spring compressor 83 93 761 and valve spring depressor 93 779 and refit the valve cones.
4 Place Valve clearance gauge 83 93 753 across two of the camshaft bearing seats with the depth gauge against the end of the valve stem.
5 Check that the maximum depth of 20.5 mm reaches down to the end of the valve stem (valve clearance gauge does not bottom in the bearing seat closest to the depth gauge), see Checking valve clearances.
6 Then check that the minimum gauge depth of 19.5 mm does not reach down to the end of the valve stem. The correct valve clearance is between the minimum and maximum gauge depths. If the clearance is less than the minimum, the valve stem must be shortened, and if it is greater than the maximum the valve seat must be reground.





7 Remove the protective sleeves and fit the valve tappets.
8 Fit the camshafts and bearing caps, starting where the cams point downwards and press on the tappets. Bearing caps marked 1-5 for the inlet side, 6-10 for the exhaust side.
Tightening torque 15 Nm (111 ft. lbs.).

IMPORTANT: The black bolts have an oil way and should be fitted on the spark plug side.

9 Line up the marks on the camshafts with their timing marks.

Valve-gear timing





When the pistons in cylinders No. 1 and No. 4 are at top dead center, the mark on the crankshaft pulley should be in line with the timing mark on the timing cover. When the timing marks on the camshafts are in line with those on the bearing caps, the inlet and exhaust valves for cylinder No. 1 are closed. As the valves open, they extend beyond the face of the cylinder head and into the zone where the pistons change direction. If the setting of the crankshaft and valve gear is altered, the valves and other vital parts of the engine will be damaged.

Valve gear (in car)
To remove





1 Unplug the connectors and remove the ignition discharge module and spark plugs. Undo the bolt securing the crankcase breather pipe on the camshaft cover and remove the nipple for crankcase ventilation and vacuum from the camshaft cover. Remove the camshaft cover.





2 Rotate the crankshaft to the 0 mark, remove the chain tensioner and dismantle the camshafts. Cover the space for the sprockets and timing chain to prevent valve cones and seals from dropping into it.

IMPORTANT: Keep all dismantled valve gear parts in valve stand 83 93 787.

3 Lift out the tappets, using magnetic tool 83 91 401.
4 Fit protective clam 93 746 around the valve springs to protect the tappet sliding surfaces. Note the position of the collar.





5 Rotate the crankshaft until the piston in the cylinder concerned is at top dead center. Lock the engine us if flywheel locking segment 83 94 868 and fit the air nipple for spark plug hole 83 94 173. Connect the compressed air and pressurize the piston and valves.





6 Press down the valve disc with Valve spring compressor 95 246 and remove the valve cones.
7 Lift out the spring cap and valve spring and remove the washer with valve guide seal using 83 94 157.

To fit





1 Fit the washer with valve seal using pliers for removing valve guide seals 83 94 157.
2 Fit the spring and spring cap and fit the valve cones in the spring cap's groove.





3 Disconnect the compressed air, remove the air nipple and the flywheel locking sigmer
4 Turn the crankshaft to the 0 marking and then 450.





5 Remove the protective sleeves and fit the valve tappets.
6 Fit the camshafts and bearing caps, starting where the cams point downwards and press on the tappets. Bearing caps marked 1-5 for the inlet side, 6-10 for the exhaust side.
Tightening torque 15 Nm (11 ft. lbs.).

IMPORTANT: The black bolts have an oil way and should be fitted on the spark plug side.

7 Line up the marks on the camshaft with their timing marks and turn the crankshaft back to the 0 mark.





8 Fit the camshaft sprockets and chain. Start with the inlet side camshaft. Do not tighten the bolts yet!
9 Prepare the chain tensioner for fitting by pressing down the catch and pushing in the chain tensioner.
10 Fit the chain tensioner, using a 27 mm socket.
Tightening torque 63 Nm (47 ft. lbs.).
11 Fit the chain tensioner plug with push rod and spring.
Tightening torque 22 Nm (16 ft. lbs.).
12 Check that the chain runs correctly on the chain guides. Rotate the crankshaft two turns and check the settings of the flywheel and camshafts. Tighten the camshaft sprocket bolts.
Tightening torque 63 Nm (47 ft. lbs.).
13 Clean the sealing surface of the camshaft cover with benzines.
14 Apply a soap solution to the opening in the camshaft cover and fit the cover, starting at the opening end. Then continue all the way round, on both the inside and outside.
Tightening torque 15 Nm (111 ft. lbs.).





15 Fit the nipple for crankcase ventilation and vacuum for the camshaft cover. Refit the bolt securing the crankcase breather pip on the camshaft cover.
16 Fit the spark plugs.
Tightening torque 28 Nm (21 ft. lbs.).
17 Fit the ignition discharge module.
Tightening torque 11 Nm (8 ft. lbs.).
18 Plug in the ignition discharge module's connector.

Valve seats





Use a cutter set with T-wrench 83 95 204, valve seat cutter 83 93 936 (60°) and valve seat cutter 78 61 040 (45).
Valve seat angles, inlet and exhaust valves: 45°.
Regrinding angle: 60°.
Valve seat width: Inlet valve 1.0 - 1.5 mm.
Outlet valve 1.5 - 2.0 mm
Press home the guide spindle into the valve guide from the valve seat side. Cut clean the valve seats in the cylinder head with a 45° cutter. It may be necessary to remove the hard surface on the exhaust valve seat with an abrasive cloth. In most cases, the valve seat width will be too great after cutting and must be reduced. Use a 60° correction cutter to reduce the width.
Apply a thin layer of grinding paste on the valve seat and insert the valve into the cylinder head. The grinding paste must not come in contact with the valve stem. Rotate with the grinding tool a few times. Clean off the grinding paste thoroughly and check the contact surface with e.g. marking ink. Repeat the grinding where required and precut if necessary.

IMPORTANT: Clean off the paste thoroughly after grinding and make sure the paste does not reach the valve guide

Checking valve tightness
1 Clean the combustion chamber and valve seats for the exhaust valves. Use a rotating wire brush for example. Wash the cylinder head.
2 Fit the inlet valves and new exhaust valves. Fill the inlet and exhaust chambers with mentholated spirits. Do not spill.
3 Check all valves for leaks. The fluid may dampen but not run out. If the valves are tight, fit the cylinder head, see Fitting of cylinder head.
4 If the valves leak, clean and precut the valve seats and grind with paste. Check the valve clearances, see Checking valve clearances.

Hydraulic tappets Description
The valve gear incorporates hydraulic tappets which keep the valve clearance within a limited working range of 2.05 mm (0.081 inch), which is between 18.75 and 20.8 mm (0.738 - 0.819 inch) from the cam to the valve. Each tappet has two storage chambers and or high-pressure chamber, which is sealed against one of the storage chambers by means of a spring-loaded ball valve. A return spring in the high-pressure chamber acts on the sliding plunger so that any clearance between the tappet and the base circle of the cam is eliminated. At the same time, the high-pressure chamber expands and makes up the oil volume to compensate for leakage losses in the gap between the plunger and cylinder which occur at actuating pressure. Under some conditions the hydraulic tappets may give rise to a chattering noise of varying intensity. In most cases this noise will be short-lived and no remedial action will be necessary. Details are given in the following of the most common types of noise, the most probable cause of the noise, and preliminary action which may be taken to eliminate the noise.

Valve noise
1 Valve chatter after the car has been parked for longer than 48 hours. During a period of prolonged parking, oil drains out of the tappets' high-pressure chambers and allows air to enter. For a period of about 15 minutes after the engine has been started, valve chatter will be heard until the air has been purged from the valve tappets. Engine speed should not be allowed to exceed 3000 rpm until the noise has ceased. See point 4.
2 Valve chatter on starting the engine after an oil change. If valve chatter did not occur before the oil change it will disappear of its own accord when the engine's oil pressure reaches its normal operating level.
3 Temporary noise on starting a cold engine. This noise is perfectly normal and will disappear of its own accord when the engine's oil pressure reaches its normal operating level.
4 Valve chatter when the engine is started after work has been carried out on it involving turning it over by hand or on the starter motor. The noise is due to one or more of the tappets having been drained of oil and will therefore disappear when the engine has been running for a while. At worst, it may take up to 15 minutes at 2000-3000 rpm for it to disappear. At lower engine speeds it will take much longer to expel the air. At higher engine speeds there is a danger of damaging the valve tappets.





5 Noise after fitting new valve tappets. Cause and rectification, see point 4.
6 Noise occurring after a short period of idling when the engine is hot. If the engine is run at 1500 rpm or more, the noise will disappear after a while. The cause of this noise is low oil pressure in the hydraulic valve tappets at idling speed.
7 Noise which occurs at high engine speeds and disappears when the engine has been idling for a shorter or longer period. This noise is due to an excessive amount of air in the oil at high engine speeds. The ingress of air is due to leakage on the suction side of the oil pump, such as a leak in the suction pipe.
8 Noise from an individual tappet, regardless of how the car is driven. The most likely cause is a particle of dirt having become trapped in the non-return valve of the tappet. The easiest way to identify a faulty tappet is to switch off the engine, remove the camshaft cover and press on all tappets not under load. The tappet that feels light (springy) or spongy is the faulty one. Replace the faulty tappet or tappets.

Checking valve clearances





This method presupposes that the cylinder head has been removed.
Check and adjust the valve clearance relative to the working range of the tappet.
The tolerances for checking valve clearance are 19.5 ± 0.05 mm minimum and 20.5 ± 0.05 mm maximum.
The valve clearance settings are 20.0 minimum and 20.4 maximum, with a nominal clearance of 20.2 mm.
Valve clearance is equivalent to the distance between the end of the valve stem and the camshaft bearing seat.
Before valve clearances can be checked, the camshafts and valve tappets must first be removed.
Valve clearance gauge is checked with 83 93 753 as follows:





Place the valve clearance gauge across two of the camshaft bearing seats with the depth gauge against the end of the valve stem.
Check that the maximum gauge depth of 20.5 mm actually reaches down to the end of the valve stem (noticed by the valve clearance gauge not bottoming against the bearing seat closest to the depth gauge).
Then check that the min depth 19.5 mm does not reach the end of the valve stem spindle. Correct valve position should be between the depth measurement min and max values. If the valve position deviates from the given measurements, adjustment are done on the valve spindle or valve seat. The valve spindle is shortened if measurement is below the min value and the valve seat is machined if the max value is exceeded. When adjusting the valve position, set this at nominal value 20.2 mm.

Chain tensioner, timing chain
To remove





1 Raise the car, turn the right-hand front wheel outwards and disconnect the power steering pump pipe from the sub frame.
2 Turn the crankshaft pulley round to the 0 mark and drive wedge 83 95 238 between the oil sump and sub frame.
3 Remove the right-hand engine mounting with yoke.





4 Take the strain off the belt tensioner with belt tensioner reliever 83 95 254 and insert a 3 mm Allen key in the hole.

IMPORTANT: Be careful so that the belt tensioner does not bend at its end position!

5 Unscrew the idler pulley's retaining bolt slightly.
6 Remove the plug.
7 Extract the locating pin and spring.
8 Remove the chain tensioner, using a 27 mm socket.

New Tensioner
A new chain tensioner is delivered with the spring tensioned. Remove the pin, plug, spring and push rod. Then follow the instructions for fitting of a previously used chain tensioner.

Fitting of previously used chain tensioner





1 Prepare the chain tensioner for fitting by pressing down the catch and pushing in the chain tensioner.
2 Fit the chain tensioner, using a 27 mm socket.
Tightening torque 63 Nm (47 ft. lbs.).
3 Fit the chain tensioner plug with push rod and spring.
Tightening torque 22 Nm (16 ft. lbs.).
As the plug is screwed in, the spring pushes the tensioning arm out and so tightens the chain.
4 Fit the idler pulley.
5 Fit the drive belt, check the position of all belt pulleys and tension the multigroove belt.





6 Fit the right-hand engine mounting.
Tightening torque: 50 Nm (36 ft. lbs.).
7 Remove the wedge and mount the power steering pump pipe on the sub frame.
8 Start the engine and run it at idling speed for a while. Switch off the engine and check that the belt is positioned correct

Replacement of timing chain (in car)





If replacement of the timing chain is to be carried out in situ, the chain guides and camshaft sprockets must be in good condition. Inspect this with the chain tensioner and timing cover removed.

Checking
1 Remove the ignition discharge module, spark plugs and camshaft cover.
2 Align the crankshaft and camshafts with their respective timing marks.





3 Check chain wear by removing the chain tensioner plug complete with spring and locating pin, and remove the chain tensioner without changing the position of the piston, see Replacement of timing chain (in car).
The protruding part of the chain tensioner must not be longer than 15 mm. If it is, the chain must be changed.
4 Check the wear on chain sprockets and chain guide.
Chain guide wear must not be so great that the chain acts on the surface between the outer tracks.
If the surface between the outer tracks shows signs of wear, they must also be replaced and the chain changed in the usual manner.

Changing the chain





1 Cover the area round the chain with a cloth and also secure the chain with cable ties on both sides.
2 Open the chain by pressing out a link using Toolkit for timing chain replacement 83 94 637, and then removing the link with a pair of pliers
3 Couple together the new chain with the old one using Toolkit for timing chain replacement 83 94 660. Take care so the chain does not fall down!





4 Make sure that the new chain runs over the camshaft sprocket on the inlet side and fasten the end of the old chain.
5 Fit Toolkit for timing chain replacement 83 94 652 and remove the cloth and cable ties.





6 With the old chain in your hand and the new one resting over your hand, carefully feed the new chain over the sprocket as helper turns the belt pulley round.

IMPORTANT: Be sure to keep the old chain under tensions it is fed forward. It might otherwise fold itself double down at the crankshaft

7 When the new chain has been fed forward to such an extent that only a few links still remain on the inlet side's camshaft sprocket, cover the area round the chain with a cloth once again. Remove the chain link and the old chain.





8 Connect the ends of the new chain together with a chain link and pull the chain round until the link is midway between the shanks of the chain support.





9 Remove the chain link and fit a new chain lock.
Check that the inserts marked 2 are mounted in the tool. Then place the chain link's plate in the tool and align it over the link of the chain.
Press the plate in place with a force of 10 Nm (7 ft. lbs.).





10 Reverse the insert in the tool and position the tool with the V notch directly over one of the shanks of the link.
Rivet the shanks with a force of 15 Nm (11 ft. lbs.).
Repeat on the other side.
11 Check the riveting by checking the diameter of the compressed shank with a vernier caliper.
Correct dimension is on 3.4 - 3.6 mm.
12 Remove the cloth and shank support.





13 Fit the chain tensioner.
Tightening torque 63 Nm.
Fit plug, tighten to 22 Nm.
14 Turn the engine over one revolution and check the 0 marks of the camshafts and crankshaft.
15 Fit the spark plugs, camshaft cover and ignition discharge module.