I've just traded up to a K-reg '93 Griffin with 104k miles. Engine sounded smooth and quiet on idle, both cold and warm, when I bought it. Some 200 miles later, I had it serviced by a local SAAB garage, using synthetic oil (Mobil 1) and now it rattles on idle. The mechanic pointed this out, told me it was the balance shaft chains, and that it would be "really bad" if they were to break (which I don't doubt - especially after reading some of the recent comments on this BB.)

How can you tell the difference between balance shaft chain rattle and cam chain rattle ? Is the synthetic oil making the chains rattle more ? How easy is it to inspect the balance shaft chain (the cam chain can be seen just by taking off the camshaft cover - easy). The cam chain tensioner is an easy thing to check/change - how about the balance shaft chain tensioner?

Having just forked out all my dosh to buy the car, I'd like to be reasonably convinced I need to spend lots more money that I don't have on getting the chains done ...

Frankly I wouldn`t worry about which chain is causing the noise-just get it seen to before its too late !

Its one of those jobs where its wise to change everything whilst the engine is stripped down. The list can grow if the drive belt tensioner and pulleys are found to be suspect - oh and the water pump if thats noisy or weeping (like you ?) is down there too.

Good luck

Given the power of the turbos I felt that some of the components were a bit weedy

Having shopped around, the cheapest estimate I've found for stripping down and replacing both chains plus any worn parts is around £500 (parts+labour). Prices vary a lot - I've been quoted up to £1200 for the exact same job ! Just buying the two parts kits and a few gaskets/seal to do it myself costs around £300, so I think this quote is pretty good ! We'll see ...

Not doubting your garage Mark, but I had a rattle at idle that was cured by changing a 'rubber block' under the cam cover.The specialist said they go hard with age.
Is this the cam chain tensioner?

The rubber block in the cam cover is one of three chain guides which are much cheaper from people like Euro Car Parts or M1 parts in Leeds. There are two sorts for the cam cover so make sure you get the right one, I think the change was made at engine code K083010. Cost about £7.

I would get the chain renewed NOW.
I have a 2.3 16valve, the chain broke without warning (no rattling etc).
The cost was considerable, The parts alone came to £650.
Apparently it is well known in Sweden that 2.3 engine timing chains break often.
Beware the cost is frightening.
Stick with the trusted 2 litre 900.

A work colleague bought a 2.3T cheap because the chain had broke and lunched a couple of valves. He did all the rebuild work himself and it still cost him £500 in parts!!

I'm getting the work done this week. The SAABMaster who's doing the work has been recommended to me by a number of other SAAB owners - in fact, he gets most of his business by personal recommendation.

Interesting comment about the guides - I took off the cam cover - there was a slight mark on the top chain guide, but nothing unusual. You can only see the cam chain from the top, not the balance shaft chain, and this looked to be in perfect order, and properly tensioned. The actual tensioner screws into the back side of the engine block, and is relatively easy to change (assuming you can get a socket in there behind all the gubbins - was easy enough on the last 9000 I had)

All the people I have asked for quotes say that the balance shaft chain is the one that goes - the teeth start to get knocked off the idler pulley (I think they said?), and eventually the balance shaft chain either breaks or is thrown off, and generally takes out the cam chain, which is right next to it. As well as the rattle, which you can hear best from the timing-chain side of the engine about half-way down, the engine appears to "tremble" slightly at idle, presumably because the balance shafts are not rotating smoothly.

It will be interesting to see which parts are damaged when they are replaced later this week !