I think what he was getting at is that the o-ring allowed oil to be sucked into the motor, causing a runaway condition. You have two options at that point: get the air cutoff somehow, or stand by and watch your motor blow.
can get them on ebay for 50 bucks. its really not hard to rebuild them.
Any drunk monkey with thumbs can rebuild it, how do you finish balance it in the garage?
I have done all my turbos with no ballancing at all. The real ballance is when your foot touches the rad cap without being burned!!.........:hehe: