[happos2]

Originally Posted by e92livin

Bearing #8 looks rough, Why does that bearing significantly wear more then the others? What is the difference with the VAC bearings and OEM? Thanks for the useful info btw.

Answers noted below in regards to VAC question...........

As or the #8 wear, I don't know...good question.

Originally Posted by regular guy

Unfortunately no they don't. VAC uses Calico Coatings to coat factory bearings. According to the Calico web site, the coating will add an extra0.0002 - 0.0004 inch thick coating. To put this into real numbers, that would mean your bearing clearance would be reduced from 0.0010 to a range of 0.0006 - 0.0008.

Here's a link to the Calico Coatings FAQ on bearing coatings. Note they recommend 0.0020 - 0.0030 bearing/journal clearance.

http://www.calicocoatings.com/faqs/

Calico's CT-1 dry film lubricant used on engine bearings, valve springs, oil pump gears, timing and transmission gears is 0.0002" to 0.0004" thick and generally speaking does not need extra clearances. A benefit of Calico Coated bearings is the allowance for tighter clearances. Keeping in mind that bearing clearances of .002" to .003" are typical for High Performance applications.

Originally Posted by italyix

Tom,

Thank you for posting this. When you guys replace the bearing, is it a direct swap, or are tolerances taken into account, relaxed to accept the thick tws and therefor properly clearanced?

I ask as it was already mentioned herein, the VAC bearing will be even tighter as they are coated and therefor only accelerate this problem in the future.

Also, how many hours would one expect bearing replacement to take?

Thanks!

Originally Posted by DLSJ5

Good point, I'm pretty sure it's going to be tighter.

Man those bearings are beat up. Great info for the community Tom, thank you for documenting the work and posting it up, glad you guys caught this in time.