Date: Tue, 19 Oct 1999 01:43:09 GMT From: Rick and Lorie Mieras <rlmierasnopsamsplanet.net> Subject: Re: Noisy 16v - It's the timing chain!! - HELP
I have an '87 9000T with 230,000 kilometers on it--all original. Should I change my shain just because of high mileage? I have a slight rattle at idle, engine hot. johann wrote: > Dear Malcolm, > A couple of places are Eurocarparts 0541 506 506 (mail order) and German > and Swedish 0181 917 3883 - chains £20 + vat, tensioner £25 +vat (approx). > Beware ! > your guides are probably worn as well and this is an engine out job or if > you are cunning a head off job. Changing the chain means spliting the old > one joining it with the new one and winding it through while keeping the > crank and valve timing in sync -tricky. Seperating the chain is quite easy > with cheap tool but joining the ends succesfully needs a high quality > specialist tool - in the end its probably better to get a garage to do it - > there must be some Saab specialists in your area who are not main dealers. > I had rattle and tapping on my T16 (185 000 miles) - I took the lid off and > replaced 2 lifters, the chain and guides were in good condition but the > tensioner was shot (old style) so I replaced this with the later ratchet > type. > The result was the elimination of all the noises - sounds like new. > Timing chain rattle is like a clatter - noticable at any speed but at idle > you should clearly hear it at the back of the engine, if you have an old > type tensioner (Large flat bolt) you will hear it for a few second on start > up as the tension is maintained by oil pressure and also at idle on a hot > engine if the oil thins and can't maintain the pressure. On the later > tensioner (large bolt with centre bolt) if you remove the centre tensioner > you can measure the amount of exstension of the ratchet and thus the wear > in the guides and chain - I think anything over 11mm is bad news. > The best place to start is to get the lid off and check the guides and > tensioner - you can give the chain a rough check by holding it at the apex > as it goes round the sprocket - if you can pull it away from the sprocket > teeth even the slightest amount then its worn. > Don't delay doing anything about this - if the chain snaps you are looking > at a complete engine rebuild at least with the addition of a new turbo if > valve bits try to get out of the exhaust manifold. > > Hope this helps. > > Johann
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