4G63 main bearing journals

Hey Andrea, looking at the 4G63 practical engine building course. Question, what measurement did you use to zero the bore Guage too in order to check out of roundness in the main bearing journals ?

What you're doing it looking at the relative differences of the diameter at different points around the bore.

Personally, I'd suggest using the point 90 degrees to the parting line, across the bore, as the zero reference, and work around the bore from there at several points, such as 30, 60, 90 degrees each way and if you notice a change, do a few more around that point, or the points. I'd also suggest checking for taper, so do close to the 'front' and 'back' edges at the same time.

Hey, thanks alot for clearing that up. 👍