Date: Tue, 17 Sep 2002 11:16:14 GMT From: "Jussi Aaltonen" <jussi.aaltonennopsamam.pp4.inet.fi> Subject: Re: B234 2.3 engine damage
Balancing shaft chain failures are quite common, or even typical, in earlier B234 engines. Balancing shafts rotate at twice the engine speed and chain load naturally oscillates due to eccentrity of shafts . There for balancing shaft chain wears much more rapidly than the timing chain. Timing chain typically lasts over 350 000 km, balancing shaft chain lasts 1/2 - 2/3 of that. There's nothing to do to slow down the wear, all thought rumours tell that keeping oil level slightly above MAX makes it last longer, sooner or later the chain failure occurs anyway. The best thing is to be prepared and change the chain before it breaks. Balancing shaft chain as well as the timing chain becomes noisy well before the actual failure. Condition of the balancing shaft chain can also be seen from the vibrations of the engine, as the chain and pulleys wear the engine tends to begin vibrating more. Jussi "Vesku" <vtmnopsamoint.net> wrote in message news:am57k0$n6$1nopsam-news1.kolumbus.fi... > Saab 9000 2.3 turbo -91, B234 engine, clacking noise begun and oil pressure > dropped on autobahn. > > When opened the oil pump and removed sump, found that big end bearing 4 is > badly damaged and others worn. It seems there is kind of metal powder all > around. Ie heard one possible cause for this failure could be balance shaft > chain that will drop metal when it is worn. > > Any experiences on similar failure ? What could cause this ? Is it a common > failure ? Is it somehow related with turbo, or could happen as well with > any B234 non turbo ? > > br Vesku > >