Technical Car Experts Answers everything you need: How to replace timing chain on saab 900 ?

The timing chain is covered under steps for motor disassembly, so here is that proceedure. Use what you need from it:

• Step numbers below refer to numbers used in the illustrations.
• Remove the engine and place on a suitable trolley.
1. Drain the oil and remove the starter motor.
2. Remove the belt tensioner, alternator and support bearing bracket complete with tube and inner drive-shaft joint.
3. Install holder tool No. 83 94 728, or equivalent, on the engine and lift the power train onto floor stand tool No. 78 74 878, or equivalent.
4. On models with automatic transmission, remove the protective plate and undo the torque converter retaining bolts.
• Rotate the flywheel by means of the crankshaft pulley to bring each bolt up to the opening where it can be removed.
5. Immobilize the torque converter by means of a 50-mm long fully-threaded M6 bolt.
6. On all models, remove the transmission
7. Disconnect the electric leads from the ignition discharge module, remove the oil filter pipe bracket and remove the preheating hoses from the throttle body.
8. Remove the bracket for the electric leads.
9. Undo the crankcase breather nipple and remove the intake manifold steady bar.
10. Remove the intake manifold retaining bolts and lift away the manifold.
11. Remove the bracket for the engine mounting.
12. Remove the filler pipe from the expansion tank.
13. Remove the heat exchanger pipe.
14. Remove the water pump complete with sleeve and O-rings.
15. This step is not applicable to this model.
16 This step is not applicable to this model.
17. Remove the power steering pump complete with bracket.
18. Remove the exhaust manifold.
• In regard to the two-piece exhaust manifold, first remove the inner section and then the outer section.
• Note that spacer sleeves are fitted on the outer studs only.
19. Remove the oil filter and adapter housing.
20. Remove the crankshaft sensor and unplug the oil level sensor connector.
21. Remove the thermostat housing cover.

22. Align the mark (0°) on the flywheel or driver disc with the mark on the end plate.
23. Install flywheel locking segment 83 94 868 and remove the crankshaft pulley.
24. Remove the flywheel locking segment and remove the flywheel or driver disc.
25. Remove the ignition discharge module or cover plate and disconnect the ignition cables (as equipped).
26. Remove the spark plugs and camshaft cover.
27. Remove the chain tensioner.
• First remove the plug and then use a suitable 27 mm socket.
28. Remove the camshaft sprockets and position the chain so that it will not obstruct removal of the cylinder head.
29. Remove the cylinder head.
• Start with the timing cover bolts and continue in reverse assembly order.
• Use protective collar tool No. 75 19 531, or equivalent, to collect the bolts.
30. Swivel the engine into a suitable position and remove the oil pan.
• Do not remove the guide sleeve from the cylinder block.
31. Remove the oil pump and the timing cover.
32. Remove the top chain guide and chain tensioner for the balance-shaft chain.
33. Remove the idler sprocket and balance-shaft chain.
34. Remove the oil pump driver and sprocket from the crankshaft.
35. Remove the chain guides for the balance-shaft and timing chains.
36. Remove the timing chain guard and remove the chain complete with sprocket. NOTE: Rotate the balance shafts through 180— so that the weights face upwards and then remove them, exercising the utmost care to avoid damaging the inner bearing shells.

And reassembly is as follows:

7. Apply a bead of Loctite 518, or equivalent, about 1 mm thick along the flange of the end plate and install the end plate, being careful of the seal.
8. Install the flywheel or drive plate but do not tighten.
• Apply Loctite 270D, 0r equivalent, to the bolt threads.
• Install flywheel locking segment tool No. 83 94 868 and tighten the to: XXXXX XXXXX (59 ft. lbs.) and 95 Nm (70.3 ft. lbs.).
9. Align the 0°mark on the flywheel or driver disc with the mark on the end plate.
10. Lubricate the bearing surfaces on the balance shafts and in the bearing housings and insert the balance shafts into their respective tunnels, taking the utmost care to avoid damaging the bearing shells inside. NOTE:
• The shaft with the smaller thrust ring marked INL is the one for the inlet side of the engine.
• The shaft with the larger thrust ring marked EXH is the one for the exhaust side of the engine.
11. Check the timing chain and install the sprocket and chain onto the crankshaft end and install the chain guard.
12. First install the fixed chain guide, which is common to the timing chain and balance-shaft chain, and then the pivoted chain guides for the timing and balance-shaft chains.
13. Install the balance-shaft sprocket and the oil-pump driver onto the crankshaft end.
14. Cock the chain tensioner and insert a paper clip or the like through the hole in the cylinder to prevent triggering of the tensioner.
• Before this, make sure that the plunger is turned to the position where it really is pressed out by the spring.
15. Install the chain tensioner and tighten to : 10 Nm (7.4 ft. lbs.). CAUTION: To prevent damage it is extremely important for the correct torque to be applied when fitting the chain tensioner.
16. Inspect the balance-shaft chain and install it and the idler sprocket so that the setting marks behind the balance-shaft sprocket and on the bearing housing are in line with each other.
• Tighten the chain between the crankshaft and balance shafts.
• Install the idler sprocket last.
• Hold the bolt in place with your thumb, mesh the teeth of the sprocket with the chain and roll the sprocket along the chain into position.
17. Install the top chain guide, pull the chain slightly away from the cylinder block and trigger the tensioner.
• Press the tensioner inwards to check that there is a certain amount of play
. - Rotate the crankshaft one revolution and then check that the chain is set up correctly.

18. Make sure that the flanges on the timing cover are perfectly clean and apply a bead of Loctite 518, or equivalent, about 1 mm thick along the middle of the flanges.
19. Install the timing cover and tighten to: XXXXX XXXXX (16 ft. lbs.).
20. Install the oil pump.
21. Install the oil pump pressure pipe and check that there are no impurities or other foreign matter in the oil pan.
22. Make sure that the flange on the oil pan is scrupulously clean and apply an even layer of Loctite 518, or equivalent, along it.
• Swivel the engine into a suitable position and install the oil pan, then tighten to: XXXXX XXXXX (16 ft. lbs.).
23. Swivel the engine round again and rotate the crankshaft through 45°.
• Install the cylinder head, using a new gasket.
• Check that it is correctly seated on the locating pins and that the chain is not trapped.
• Using the sequence shown, tighten the cylinder head bolts in three stages: Stage I: 60 Nm (44 ft. lbs.).
Stage II: 80 Nm (59 ft. lbs.).
Stage III: A further quarter-turn (90°).
24. Install the two bolts between the timing cover and the cylinder head and tighten to: XXXXX XXXXX (16 ft. lbs.).
25. Check that the camshafts are in alignment with their setting marks and turn the crankshaft back to the 0°mark.
26. Install the camshaft sprockets and chain.
• Start with the camshaft on the inlet side.
• Do not tighten the bolts yet.
27. Prepare the chain tensioner for fitting by pressing down the catch and pushing in the chain tensioner.
28. Install the chain tensioner, using a suitable 27 mm socket, then tighten to: XXXXX XXXXX (47 ft. lbs.).
29. Install the plug for the chain tensioner with push rod and spring, then tighten to: XXXXX XXXXX (16 ft. lbs.).
30. Check that the chain is correctly seated in the guides.
• Rotate the crankshaft two complete turns and check that the timing marks on the flywheel and camshafts are still in alignment.
31. Tighten the camshaft sprocket bolts to: XXXXX XXXXX (47 ft. lbs.).
32. Clean the flanges of the camshaft cover, using a suitable solvent.
33. Apply soap to the open end of the camshaft cover and install the cover, starting at the open end.
• Then tighten the bolt located furthest to the front at the timing end.
• Then continue all the way round, on both the inside and outside.
• Tighten all camshaft cover bolts to: XXXXX XXXXX (11 ft. lbs.).
34. Install the spark plugs and tighten to: XXXXX XXXXX (20.7 ft. lbs.).
35. Install the ignition discharge module or ignition cables and the cover plate and tighten to: XXXXX XXXXX (8 ft. lbs.).
36. Install flywheel locking segment tool No. 83 94 868 and tighten the crankshaft pulley to: XXXXX XXXXX (129.5 ft. lbs.).
• Remove the locking segment.
37. Install the exhaust manifold using a new gasket and tighten to: XXXXX XXXXX (18.5 ft. lbs.).
• If the exhaust manifold is of two-piece type, install the outer section before the inner section.
• Check that the contact surfaces for the front pipe are level with each other.
• Note-that spacer sleeves are fitted on the outer studs only.
38. Plug in the oil level sensor connector and install the adapter housing with oil filter.
• Install the crankshaft sensor and the thermostat housing cover.
39. Install the power steering pump and bracket.
40. This step is not applicable to this model.
41. This step is not applicable to this model.
42. This step is not applicable to this model.
43. Lubricate the O-rings with Vaseline (petroleum jelly) and install the water pump and water pipes from the expansion tank and heat exchanger.
• Install the clips for the crankshaft sensor cable at the same time.
44. Install the bracket for the engine mounting.
45. Align the intake manifold gasket with the aid of guide pins tool No. 83 94 736 and install the intake manifold, then tighten to: XXXXX XXXXX (16 ft. lbs.).
46. Install the intake manifold steady bar and connect the crankcase breather nipple.
47. Connect the cables for the temperature sensor, and the hoses for the throttle body.
• Install the oil filler pipe bracket.
48. On models with automatic transmission, check that the torque converter is properly seated in the transmission casing and that the locking screw is fitted.
• On all models, install the transmission into place and tighten the bolts.
49. On models with automatic transmission, apply Loctite 270D or equivalent, to the torque converter bolts threads, then install ant tighten the bolts to: XXXXX XXXXX (44.4 ft. lbs.).
50. On all models, install a lifting sling to the engine and lift it off the stand.
• Remove the fixture and lower the engine onto a trolley.
51. Install the bearing bracket with tube and inner driveshaft joint.
• Install the alternator, connect the leads and install the belt tensioner.
52. Install the starter motor and connect the cables.
• Check that the oil plug is properly tightened.
• The engine is now ready for installation into the car.