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Discussion Starter · #1 ·
Well, I was sort of hoping that when I got my timing cover off, I'd see a load of really worn out gears and chains.

However, I have to say that to the naked eye everything in there looks great! I haven't removed everything yet, so I haven't closely inspected things.

This is kind of annoying. I am sure the rattle was chain related (my skeptical friend moved the car just before I took it apart, and was horrified by the noise!) Since it was so intermittant, and so loud, I wonder if it was a tensioner sticking, or losing pressure or something?

Anyway, I suppose I have no choice but to replace everything now I am there, but it is annoying - not as satisfying as replacing obviously worn bits.
 

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John...

You've clearly done it for the sense of satisfaction of a job well done!

You know I did mine a few weeks ago, I'm not sure if I'd have been disappointed at not finding soemthing significant. As it was I found my exhaust balance shaft sprocket devoid of any teeth whatsoever (when I first saw it I thought it was an idler or tensioner pulley) and two of the chain slipper bars broken in two. That said, everything else *looked* ok until I looked properly. The crankshaft timing chain sprocket was showing wear and slight hooking but the camshaft sprockets were ok. It would have been stupid not to replace it all while it was stripped.

With all the work you've done on the head (how were the valve clearances BTW?) I reckon you've removed any source of noise - maybe what you had was a cumulative collection...

I'd still like to know where all those sprocket teeth of mine went..

Greg
 

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Just a thought from my experiences.

The idler pulleys on the 'fan belt' can make an horrendous chain like noise as they fail !! and it's not fun when they do fail as you loose the water pump and power steering.

I had to have an engine changed when I was a victim of the 'Black Death'. I had been using Halfords full synthetic oil, changed about every 6000 miles. After a lot of fast motorway use, the oil turned to a black junge, blocked the oilways, the balance shafts spinning at twice crankshaft speed need plenty of oil and seize. This doesn't usually stop the saab, it just rips all the teeth off the balance shaft sprocket !!!!!
 

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Discussion Starter · #4 ·
Tom: I was originally hoping that the noise was belt related (even though my Saab specialist told me it was chains). Especially when my water pump bearing started to disintegrate.

However, the tensioner was not flapping or vibrating at all. Also, although it's hard to be 100% certain, the noise really did not seem to be coming from the tensioner area at all. When I dismatled it, the pulleys seems to spin freely without excessive play, and the tensioner still moves and does not seem to be leaking.

Greg: haven't got the head off yet (too many other things to do other than work on the car), but I think it probably is stupid not replace everything while I am there, but I'll see when I've got everything on the bench. If any of the old parts look totally A1, maybe I should keep the new ones and advertise them in classified section Can't send them back, because I bought kits.
 

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Discussion Starter · #5 ·
Hey, while we're on the general subject, the Haynes seems to suggest removing the electric fan cover and the oil cooler to remove the head/turbo. I can't see a good reason for this, but am I missing something?
 

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I have replaced the timing chain on 2 2l 9000's without balance shafts. On both the pulleys were ok but the chains had worn. Slack could be seen in the section between the cam pulleys which went on the new chains. You may see wear in the old chains if bent sideways compared to the new ones. On one car the old worn chain was catching the timing cover giving a loud metallic noise.
 

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Best way to check for chain wear is how Saab recommend, remove the centre bolt of the tensioner, then the main tensioner and measure the section of tensioner that has moved out of the tensioner body. I believe you are allowed 14-15mm before chain replacement is necessary.
 

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Discussion Starter · #8 ·
Well, having pulled it all apart, I'd be hard pressed to tell any of the new parts from the old parts, even with close inspection. The plastic parts have very slight grooves where the chains run, so it seems sensible to replace them. I can't see any difference in chain lengths (the old ones didn't seem slack either) and the sprockets all look identical. Not sure how to tell if the tensioners are worn or not!

Still, it's got me scratching my head for sure. I still can't decide whether to just replace everything or be selective. And I really hope I haven't wasted my time and money on a wild goose chase.
 

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Hi John..

Glad and sad I think...


I think Paul may have a point with maybe the chain rattling on something - especially if either of the tensioners weren;t tensioning properly ... were they ratcheting out and staying out??

I know I could have probably got away with replacing just the broken/worn components on my re-build (that would have been the slipper/guides and the balance shaft sprocket) but that way just presents you with a motor in which you have critical parts that WILL fail before others... I'd personally just bite the bullet and replace the lot - IMHO a long term investment...

Just out of interest, what were the camshaft bearing surfaces like?? No excessive end-float?

Cheers

Greg
 

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Discussion Starter · #10 ·
I decided to forgo pulling the head apart... not enough time. So, I've just cleaned it up a bit, and I'm putting it back on. There doesn't seem to be any play in the bearings though.
 

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Originally posted by Neil(CS2.3T):
[qb]I believe you are allowed 14-15mm before chain replacement is necessary. [/qb][/b]
I'd heard elsewhere that it's 11mm. It's quite important to me as I've just pulled the tensioner off mine on the way to removing the head and would like to know. The tensioner on mine is extended 10.5mm.
 
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