Date: Wed, 07 Jun 2006 09:16:57 +0100 From: "Charles C." <c.k.christacopoulos.removeme.nospamee.ac.uk> Subject: Re: Saab 900 Classic Timing chain issue
James Rosenkranz wrote: > "Charles C." <c.k.christacopoulos.removeme.nospamee.ac.uk> wrote in message > news:4485ecdb$0$1235$db0fefd9nospam.zen.co.uk... >> You can hear a slapping chain with the car stationary. Open the bonnet >> (hood or whatever you call it) accelerate the engine to say 4000 revs. >> >> If you stop the acceleration suddenly listen for metallic noise. Repeat >> and decelerate gently you should not hear a noise. >> >> Under acceleration the chain is tensioned so it is the moment >> acceleration stops that it will move. >> >> If it helps at all. >> >> Regards >> Charles >> >> PS. I don't think you are going to hear a worn chain as such only as a >> loose chain the hits other parts anyway. > > Hi Charles- > > The metallic "pinging" has largely dissappeared after the tensioner > replacement and been replaced by a rattling sound that is pretty constant > regardless of RPMs. In which case we all hope it is the chain and not something worse. This and your other messages (and rereading your original post) now point more to a chain. I take it you can hear the noise with the car stationary and the hood open ... in which case you should be able to tell if rattles come from something else. > Still some trace of the pinging upon deceleration. > I'm wondering if it could be the upper chain guide in the valve cover. I have avoided passing comment as to what part it may be ... as I have only done a chain (well I did the complete engine) in a 1983 900 and yup the chain was long gone. I am not familiar with the engine in your car ... tween cams for example hence I am keeping quiet. You sound capable of replacing the parts you mention yourself ... if you can afford them go for it. BTW. Effectively with the wear on sprockets, guides, the linkages of the chain and the lobes of the chain you end up with a chain which is physically longer and feels even longer because of the sprockets. Any length of it that has to travel in a straight line will produce movement and hit the guide. ============================== Do a process of elimination of what else is nearby that could produce a rattling sound ... I had many V belts do that as parts were not perfectly aligned (do you have a V belt or serpentine belt ... probably the latter in which case it can't be the belt itself ... the belt has a tensioner too ? ...), alternator bearing? water pump? Camshafts gone? No. Oil pump ... I doubt it would make any noise. Power steering pump? I am just taking some wild guesses above in case you get a pointer. Regards Charles -- Please remove _removeme_ to reply.
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