WPC Treated Bearings
Pictures show factory bearings (left) compared to WPC treated bearings (right).
Here's a possible solution I haven't yet seen discussed. The idea was first pitched to me by Auto Talent in Los Angeles. I forgot all about that, but then re-pitched by m3post user 'e92zero.' WPC has a micro shot peening process that they say reduces friction without changing dimensions of the treated surface. WPC uses this treatment on many surfaces including engine bearings. It's hard to imagine engine bearing thickness wouldn't be affected by the WPC treatment because we're looking at clearances in the ten-thousandths of an inch. E92Zero proposed to send my reference bearings to WPC for treatment then let me take proper measurements when they returned. But as pure luck would have it, Auto Talent had already sent out a complete set of bearings for the WPC treatment and they arrived while I was in the area collecting all of the data for this article.
While on my way to EAS to measure the VAC coated bearings, Auto Talent was gracious enough to allow to measure two sets of bearing shells (two uppers, two lowers). I documented and photographed the results as follows:
| Factory Reference | WPC-1 | WPC-2 |
| Top (Blue) | 0.07885 | 0.07875 | 0.07870 |
| Bottom (Red) | 0.07865 | 0.07860 | 0.07850 |
Just as I had hoped, the bearings were thinner than stock. After collecting the measurements, Auto Talent allowed me to take the same two specimens to Van Dyne Engineering for our much more thorough bearing measurement tests. While at Van Dyne Engineering, we put the WPC coated bearings in our factory connecting rods to obtain proper clearance measurements. I torqued the WPC treated bearings into two factory connecting rods to obtain the data listed below.
| WPC-1 | WPC-2 |
| Crank Journal | 2.04655 | 2.04660 |
| Rod Bore | 2.04825 | 2.04820 |
| Bearing Clearance | 0.00170 | 0.00160 |
Thanks to Sam and Zolti @ Auto Talent for letting me take these measurements and share them with the community. And another shout out to e92zero for bringing the WPC treatment back to my attention.