Feel free to delete my post in general miata discussion.
So, maybe someone can shed some light on this situation for me:
I have two cranks, one from a previously turbo '96 and another from an n/a...believe it was 96 also.
They're sitting at the machine shop, and I plan on grinding the journals -.25mm to run my King XP's.
Turbo crank was getting ground down because rod journal #1 was .001 out of round. However, UV showed a ton of spiderweb cracking on rod journal 4 when dyed at my machine shop. Builder wouldn't send it out to get ground down.
So, I bought the second crank, looks beautiful...unmachined ever and has standard journals. That one ALSO is showing the start of this issue. You guessed it, almost in the identical spot on rod journal #4.
Is this a common issue on Miata cranks? My shop is pretty dumbfounded to be 2 for 2 on this same issue. I can't imagine most guys ever even test this. They just toss rods in and go for broke.