waiting for a
Join Date: Jan 2007
Location: Buckingham, UK
Re: 166 Big end troubles
Sorry to read about your misfortune. Gotta say, in my experience (which is frankly, extensive [not meaning to blow my horn, just being honest]) it sounds like you've had a bit of a freak failure.
Obviously the most common cause of bottom end failure in any engine is oil starvation. This is usually brought about by a combination of low oil level, cornering lateral forces and/or high rpm. Unfortunatly on Alfa's the oil pressure warning light is triggered at a lower threshold than the damage occurs. This usually leads to a bearing shell binding to the crank and spinning in the con (conecting) rod big end instead. it's this motion that scores the crank. The noise should start quietly and build up to a load-ish knocking noise over 2 or 3 miles, especially prominent at low rpm and during decelleration. it shouldn't be so evident under load. Not at first anyway. After a few more miles it will sound like a bag of nails all the time. As I say, if you experienced this gradual onset it's almost always due to a low oil level.
However, as I read your story it seems to be a sudden failure and instant loud noise. In that case it seems like a freak accident, and it may be worth replacing the pump as a precaution, but the pump must be rebuilt and inspected anyway, as it will have sucked up some of the metal fragments from the disintegrating parts.
If however your oil level was boarderline, you were driving along the motorway, radio on, and then when you slowed onto the sliproad you heard the noise, you've probably got garden variety failure.
Either way, you should be able to get the crank ground and replacement (oversize) bearing shells for around 300 quid plus labour to remove and refit. Maybe something like 6 hours? And after that your engine will be as good as new, and you shouldn't worry about it again (aside from keeping the oil level up.
Hope this info helps.
Six/twelve devils screaming
Alfa History: '78 GTV 2.0, '83 GTV6 2.5, '98 156 Selespeed 2.0, '96 GTV 2.0, '96 GTV 2.0, '05 GT 3.2 V6, '96 146 2.0ti, '99 156 2.4JTD, '01 147 1.6 Lusso.
Current Others: TVR T350 Spider, AM V12 Vantage