Yeah when I was installing my oil return/-10 AN fitting I noticed that my Gen 2 Precision 6870 Dual Ball Bearing had a taper on the small oil feed side. Have you measured it or know what size it exactly is?

 

No I haven't. I haven't looked at my turbo in a while or taken it off recently but IIRC it looked to be about the standard size. I didn't want to touch it because it was marked with paint and said something like "don't ever take this apart" lol

 

Precision turbos are great turbos! Believe it or not some people don't understand the simple fact that the oil feed should be facing up and the oil drain down, as only gravity gets the oil out of the turbo. something simple as this mistake can result in smoke and blowing the seals out "like a fat kid eating cake".

 

When clocking your turbo, some applications wont let you have the feed straight up top and the drain straight down. In this case before you tighten the compressor housing bolts down, you have up to a 15 degree pitch to work with.