Crank timing gear have any surface rust on inside?
Nitto Rods and pistons (Nitto/JE) on prepped RB30 crank or go the 3.2 big kahuna I can put you in touch with Andrew from Nitto, if you'd like to talk to him. He's a mate and lives 10 mins up the road. He's very approachable and helpful with info. Ask about Nitto materials and design R&D it's incredible.