Rattling 3.2 V6.
I picked up 3.2 v6 engine for £200. Suspected Timing chain failure. I already have a Q4. That has had all chains and tensioners done and it is sweet as a nut. Consumption is another issue, best left. However, over two days I have been stripping the spare engine down and if there are any issues about the quality of the build, the major ones would be, the variation in tightness of the bolts around the timing chain cover and on the Tensioner and guides. However, this being a 56,000 miler anecdotally, it really is in very good condition. Oil residues inside the heads and on the front housing for the timing chains are substantially absent. All very clean - and I mean very clean.
There is no evidence of "Scoring on the nylon faces of the tensioners or guides and checking the main lower chain tensioner to see if the mythical none return valve actually is there, I can confirm it is and it works. However, else where it has been stated the springs in the tensioners are very powerful and in one instance, it was said "The hydraulics" help support the springs? Well they certainly would need to in the case of this engine as the pressure they exert upon the tensioners is pathetic. Non the less, there doesn't seem to be the problem I was expecting to see - the "Dreaded Timing Chain Stretch". The engine was removed and replaced in a late Brera as a "severe rattling" was emanating from the block. I have inspected the oil filter and sure enough there are shards of white metal, almost grainy such as sand. Tomorrow, it is likely I will see the real problem when the sump comes of. The heads will also be off tomorrow and everything will be de-greased and dry stored in poly boxes whilst I get the funds together to have the remedial work done; most likely the first being a reground crank. Expert opinion seems to lead towards a spun bearing shell and damaged con-rod. I also suspect; as the fining's would need to come via the Oil Pump, I will probably need to change that too.
This all seems terribly depressing. But no! Yes it is going to cost me, but I would not spend the money if I had seen what I have been led to believe about this engine. Others more expert than me may be able to point more directly to issues other than poor power figures, high oil an petrol consumption and potentially issues about oil pressure and V.V.T. However on the evidence I have before me; this is fundamentally a very well designed engine and the quality of the casting is as good as anything I have seen. The strength of the block is enhanced by virtue of the crankshaft bearing caps being bolted through the block walls as well, thus strengthening the block and effectively encapsulating the Crank within it.
All this has spun of from my desire to supplement oil pressure across the block by using external piping directly from the Oil Filter/cooler unit. After getting the front cover off I was able to inspect the V/V.T. feed ways and the diameter of those further reinforces my view that Oil flow/pressure distribution across the block is not sufficient to support a "Proper Functioning Variable Valve Timing System" and maintain timing chain tension.
All this aside, I'm still glad I bought the Q4 and the spare engine. I think the engine is brilliantly designed but poorly manufactured. Did they run out of money or was the launch date approaching to fast for them to finish the job properly? Who can say. I think Alfa let this engine down. But I remain convinced that well throughout modifications; to oil distribution in particular, can go some way towards redemption. Is this a good engine - yes. Could it be great - yes. Is it a complex engine - no. Could a mechanical minded enthusiast overhaul it - yes. It appears complex. But once you start to take it apart, it's not complex at all The electronics are a different issue. But it is well to remember, the dealers can't fix that either. They just simply throw the faulty bit a way and stick on a new one.
Is the V6 worth buying? Yes, Yes and Yes again.