So I printed this tool in preparation for putting my oil console back on and I didn't like the surface of the alignment shaft. I mulled printing it on the resin printer for a smooth body, but figured that wouldn't be much help for the typical 3D printing mechanic. Traditional 3D printers (FDM printers) tend to create a so-called z-seam, formed by little blobs at the start of every layer. Your options are to align the blobs and end up with a seam, or intentionally space out the blobs and end up with random dots on the surface. Here is a random internet picture that shows the traditional options...
seam_position_comparison.jpg
Neither of these options are great for an alignment shaft, since the blobs or seams interfere with getting a perfect fit/alignment. So....
Image-of-no-Z-orpv-tool.jpg
Here's my solution! It dawned on me as I struggled to make a perfectly smooth alignment shaft that I could put a tiny notch in the shaft to prevent/hide the z-blobs -- without affecting the tool's functionality at all. [Update: I used this 3D printed tool on my own engine in January '26 and it worked like a champ -- allowed the OPRV to screw in easily after the filter console was torqued in place, and oil pressure was normal after repair.]
oprv-no-seam-smooth.jpg
Here it is as printed, with the shaft measuring a near-exact 17.51mm (+/- depending on ambient temps). With the notch used as a sacrificial z-seam avoider, it becomes perfectly smooth around the circumference just like its factory counterpart.
OPRV late 944 No Seam Tool.stl
If using an FDM printer, this is the better model to use. I used the Bambu Vision Encoder board to calibrate the print. After calibrating, when printed with Bambu ABS using .16mm layers, the shaft comes out to 17.51 as intended. If you are printing your own, measure it after printing and scale the X and Y dimensions in your slicer up or down as needed to get to 17.51. Once you do that, I'd argue it's every bit as good as the factory tool.
