1998 Nissan Altima Timing Chain

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  #1  
Old 02-19-11, 04:52 PM
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1998 Nissan Altima Timing Chain

I have a 1998 Nissan Altima that I am changing both timing chains on. I have everything taken off so far and I am down to the lower chain cover. I have jacked the motor up and down and have used a puller to get the chain cover off. I have taken every bolt out that is in sight and still can't get the cover off. I have it loose and it is coming apart from the motor and I can see the chains but I can't get it to come all the way off. It's like it is sealed on or something. Is there a special trick I am missing?
 
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  #2  
Old 02-19-11, 05:00 PM
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Nissan 240SX/Altima 1993-1998 Repair Guide
Timing Chain and Sprockets

* REMOVAL & INSTALLATION





1. Disconnect the negative battery cable.

2. Drain and recycle the engine coolant.

3. Drain and recycle the engine oil.

4. Remove the engine undercover.

5. Label and disconnect all appropriate vacuum hoses, fuel lines, wires and electrical harnesses.

6. Remove the alternator and bracket, upper radiator hose, air duct, and front exhaust tube.

7. Remove the intake manifold collector supports, intake manifold collector, and exhaust manifold.

8. Set the No. 1 piston at TDC on its compression stroke.

9. Remove the distributor.

10. Position a floor jack with a block of wood beneath the aluminum oil pan and remove the passenger's side engine mount.

11. Remove the cylinder head cover. Remove the cylinder head cover bolts in the proper sequence.

12. Remove the camshaft sprockets.



The stoppers on the camshaft covers prevent the upper timing chain from disengaging the idler sprocket.

13. Remove the cam bearing caps in the proper sequence and remove the camshafts. The camshaft brackets must be loosened in reverse order of the tightening sequence to prevent damage to the camshaft.



These parts must be reassembled in their original positions.

14. Loosen the cylinder head bolts in the reverse order of installation.



A warped or cracked cylinder head could result from loosening in an incorrect order. The cylinder head bolts should be loosened in two or three steps.

15. Remove the cam sprocket cover.

16. Remove the upper chain tensioner and upper chain guides.

17. Remove the upper timing chain.

18. Remove the idler sprocket bolt.



The stoppers on the front cover prevent the lower timing chain from disengaging the crankshaft sprocket.

19. Remove the cylinder head and gasket.

20. Remove the oil pan.

21. Remove the crankshaft damper.

22. Remove the front cover.

23. Remove the oil pump drive spacer.

24. Remove the lower timing chain tensioner, tension arm, and lower timing chain guide.

25. Remove the lower timing chain and idler sprocket.



To install:

26. Install the crankshaft sprocket and oil pump drive spacer.



Ensure that the mating marks on the crankshaft sprocket face the front of the engine.

27. Set the No. 1 piston at TDC on its compression stroke.

28. Install the idler sprocket and lower timing chain.

29. Set the lower timing chain on the sprockets, aligning the mating marks.



The mating marks on the timing chain assembly will be silver.

30. Install the chain tension arm and chain guide.

31. Install the lower timing chain tensioner.

32. Install a new front cover oil seal.

33. Apply a continuous bead of liquid gasket, as illustrated, to the front cover.

34. Install the front cover. Tighten the M6 attaching bolts to 56-66 inch lbs. (6.4-7.5 Nm). Tighten the M8 attaching bolts to 12-14 ft. lbs. (16-19 Nm).

35. Install the crankshaft damper.

36. Install the oil strainer and oil pan.

37. When installing the front cover, install the cylinder head. Insert, but do not tighten the cylinder head bolts.



Apply engine oil to the bolt threads and seat surfaces. Ensure that the washers between the bolts and cylinder head are properly positioned.

38. Temporarily tighten the cylinder head bolts.



This is necessary to avoid damaging the cylinder head gasket.

39. Install the upper timing chain, chain tensioner and chain guide.

40. Set the upper timing chain on the idler sprocket, aligning the mating marks.

41. Apply a continuous bead of liquid gasket, as illustrated, to the cam sprocket cover.

42. Install the cam sprocket cover.



Be careful not to damage the cylinder head gasket. Be careful that the upper timing chain does not slip or jump when installing the cam sprocket cover.

43. Tighten the cylinder head bolts in the indicated sequence to the proper specification.

44. Install the camshafts and camshaft bearing caps.

45. Install the camshaft sprockets (with the chain attached).

46. Install the chain guide between both camshaft sprockets.



The alignment marks on the upper portion of the timing chain should now be aligned.

47. Install the distributor. Ensure that the No. 1 piston is set at TDC and the distributor rotor is set at No. 1 cylinder spark position.

48. Install the cylinder head cover and tighten the attaching bolts in the indicated sequence to the proper specification.

49. Install the intake manifold collector, intake manifold collector supports, and exhaust manifold.

50. Install the alternator and bracket, upper radiator hose, air duct, and front exhaust tube.

51. Connect all appropriate vacuum hoses, fuel lines, wires and electrical harnesses.

52. Install the engine undercover.

53. Refill the engine with the correct grade and viscosity of engine oil.

54. Refill and bleed the cooling system.

55. Connect the negative battery cable.

56. Start the engine and make the necessary adjustments.

57. Check for proper operation and leaks.

| Repair Guides | Engine Mechanical | Timing Chain And Sprockets | AutoZone.com

apparently, there's a hidden cover bolt that requires engine mount to be removed, on the pass side, along with a bracket, to uncover that bolt. check that link i posted out.
 

Last edited by ukrbyk; 02-19-11 at 05:16 PM.
  #3  
Old 02-21-11, 01:40 PM
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Random question why did you decide to change the chains?
 
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Old 02-21-11, 05:56 PM
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he has his reasons, but chains do stretch.

fold a chain tight together. basically, it will look like a bar. grab one end and lift it up holding parallel to the floor.

if the opposite end of it droops down, chain is stretched. good chain stays perfectly straight.
 
  #5  
Old 02-22-11, 05:06 PM
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hope his doing them every 30k miles then. Wouldn't want a broken in chain on a car.
 
  #6  
Old 02-23-11, 06:47 AM
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Originally Posted by ukrbyk View Post
he has his reasons, but chains do stretch.

fold a chain tight together. basically, it will look like a bar. grab one end and lift it up holding parallel to the floor.

if the opposite end of it droops down, chain is stretched. good chain stays perfectly straight.
Perfectly straight ?? .......
 
  #7  
Old 02-23-11, 01:25 PM
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nothing's perfect in this imperfect world, especially things made by imperfect beings like humans.

it depends on the chain length and how it's made. his looks like a - gosh, what to compare it to.... it's really wide, with thin links, and large gaps between rollers. sprocket causes this. not like GM chains, or Honda chains, when they have them thick and substantial and rollers are tightly grouped..

so, anyhow. the longer the chain, the more of distal droop there will be. but it should not obviously bow. i'd say, 1/8 of distal displacement is within normal.

i know this cuz back in old country, we had total lack of spare parts. so, schemers will take used chain, clean, re-grease with thick grease, repack into wax paper, and try to sell it as new. it was all done on markets, so one had to really watch for it. on well used ones, difference is drastic.
 
  #8  
Old 02-23-11, 02:29 PM
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Does that mean he is also going to replace main and rod bearings plus the oil pump. Timing chains are on the same list for preventative maintenance as timing chains.
 
  #9  
Old 02-23-11, 03:15 PM
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Just to answer a question I have regarding the chain replacement timing schedule. -

Is this a non-interference engine so things just don't work right. the problems are not to costly or serious, so you can gamble and stretch timing/changing a bit.

or -

Is it an interference engine when it can let go and cause a lot of engine problems and rebuilding. I had one let go on a Friday morning in a small town in western NJ with no load on the engine and it cost a bunch to replace the upper end and I learned a costly lesson very quickly. I was 300 miles from home and commuting on week-ends and had to rent a car to get to work and get home for a week-end or two so that raised the cost even more.

It is smart to be proactive, especially with an interference engine.

Dick
 
  #10  
Old 02-24-11, 04:17 PM
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Almost all these engines that have this problem have belts that break not chains. The only engine that I can think which self destructs because of timing chain stretch is a lamborghini. Usually that happen around 100k miles. The reason for this is those engines are fit on assembly so everything is measured and built on the fly. Thats why they aren't massed produced cars. Very few are made year. As for your nissan that thing can strech all it wants. Very much worth the gamble since chains on a such a lower power enginer virtually never break. Plus if its that old its about time to get a new car.
 
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