Originally Posted by alfa_147_lusso
since purchasing my car the other day, i looked all through the service history and found that on 44k miles, the cambelt must have snapped as there is a warranty bill saying that a new cylinder was fitted as all valves were found to be bent, cylinder was fitted along with cambelt/variator etc.
there is no mention of bottom end/big shells being done.
the car has now done 73k miles (another 30k miles) - if there was a problem with the shells would this have already shown up?
also what does it sound like if there is a problem with shells/bottom end?
Although the pistons do get hit hard when a belt snaps - hence why the valves bend - rarely does it mean that this does damage to the big ends - which are designed to take big and heavy forces.
When you think about it, the pistons push on the big ends with all the power of the engine all the time - but the valves don't take much to bend at the head, so the force rarely does damage, although a good mechanic will always check. A damaged bottom end will have big end shells that are spread out - i.e. pressed into a thinner but wider shape. Personally I have only seen this once and that was because the head of the valve snapped off and jamned between the head and piston crown. This also bent the conrod, and then forced the piston through the liner and broke the block (it was on a Rover KV6 engine).
Anyway, if there were problems it would of shown up by now. It is easy to remove the sump on a 156 and then remove the shells to measure and check (or just replace) if you are concerned. You could always view it as a preventative measure. £30 and 3 hours well spent perhaps.
If you have 'failed' or worn big ends you may notice a bottom end type deep knocking around 2500-3000 rpm (unloaded) first. Sometimes this is worse at cold, although I have had some engines that only did it when warm. Never worked out why they vary.
You may also notice some signs of low oil pressure - i.e. rattles on the tappets on startup, delay in the oil light turning off when started etc
What I would say is, don't panic but listen out for noises on any Alfa as this is a common issue and best caught early. If you have time and skills to hand, remove the sump and check them all over with some plasti-guage.
Anyway, thats just my opinion.