Bottom End rattle?

[grizzo@domain.elided]

My 88 Milano 3.0 (102 K miles) exhibits a strange rattling sound at idle. It
sort of makes the engine seem "off beat" and causes some rattling in the
exhaust. At anything above idle the noise is undetectable. I know I need valve
guides as there's oil burning, but I don't think it's related. One Alfa mechanic
told me unequivocally that it was main bearing noise, An AROC tech advisor told
me that mains don't rattle, only rods do. So in a nutshell, anyone go down this
road before and can advise. 

Giovanni
88 Verde

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