Are bucket shims for mainstream Japanese cars interchangable?

Question

I have two Japanese cars ( a Mazda and a Nissan ) which use cams placed directly over the valves ( no rocker arm ) which contact a shim sitting on top of a bucket over the valve. Are the shims used by different manufacturers all the same circumference such that I could use for example Toyota shims in a Nissan or Mazda or visa versa, or are the all different circumferences? I.e. are these type of shims standardized?

Answer 1

Almost never will you find two sets of shims from different manufacturers that are identical. That said, it's a shim. You can reshape a larger one if need be, though it's a hack job.

So unless you really want to go DIY, no, they're not interchangeable even if they're the right thickness.