Don't agree with this. The Twin Spark engine is an excellent engine, if you look after it correctly. Certainly changing the timing gear every 36,000 miles/3 years is important, together with regular oil changes. It is, after all, a fairly sophisticated engine, and needs looking after more than, say, a GM or Ford engine. It is, after all, an Alfa Romeo.
I agree with this. If there are particles in the oil, then change oil/filter now. If the particles are metal then I strongly recommend (as suggested before) an inspection of the main bearings.
All engines make a knocking sound after changing engine oil and especially filter
Well my engine never knocks when I change my oil/filter.
ALL engines knock after changing the oil and filter. It takes a few seconds for the oil to be picked up and fill the passageways and gallery before reaching the bearings. This is exacerbated by the variator in the Alfa engine. That's why it's not uncommon for Subaru owners to complain of poor performance after a service. The knock sensor picks up the extra vibration and retards the ignition. It will reset after 1-2 hundred miles though.
The 16V Twinspark is not really a very sophisticated engine, and as BN points out, a backwards step after the bombproof 8V Twinspark. The only 'advancements' the 16V had were:
A special cylinder coating to reduce friction- the cause of high oil consumption, I think.
Oil pump in engine front housing to allow a direct drive and packaging improvements- common nowadays.
Balance shafts on the 2 litre- like Honda and Mitsubishi, but 10 years later.
Oil/coolant heat exchanger to allow fast warmup of engine oil.
Stretch head bolts to allow constant clamping force irrespective of engine temperature.
The cast iron block damps engine noise and vibration better, but the cast lump is hardly an advancement.
Extra electronics are not really part of the engine.
The older all alloy unit was lighter and virtually as powerfull (148BHP). It used 8 less valves, still had variable valve timing, a nitrided steel crankshaft which was bombproof, cam bearings in the cylinder head (from 1954- most British engines were 25 years behind) due to Italy having such advanced foundaries and casting processes, a virtually unbreakable timing chain for the cam gear and oil pump, long life shim tappets.
The older engine doesn't lunch crankshafts, break cam belts, drop valves, drink oil, stip sump threads, wear variators worth a mention. Note however, that all these problem areas were created by the Fiat engineers, and not the Alfa engineers who were only really responsible for the cylinder head. It is also worth mentioning that in as many cases as not, it is the 16V Twinspark engine which is responsible for someone having a really bad and costly ownership experience which puts them right off the brand.
The new engine was an advancement only to compete in the emissions BS governed world. It did not keep Alfa ahead of the opposition, only enough to keep up. The fact the old alloy block had a life of 41 years is testimony it was right frist time. If the 16V unit was a horse, I'd shoot it. The only favour it has done Alfa is to remain in business. I do know it has good performance and fans, but it really is nowhere as good as it's charasmatic predocessor. You may not agree with my opinion, but it is backed up with facts.