Another bolt size needed

[ck5566]

Originally Posted by COBALT

Make sure you buy a grade that matches the grade in the stock bolt, or something that won't cause damage to your mount over time. You don't want your bolt to be harder than the threads in the mount or the bracket, or you'll end up with the same problem I have: a loose mount that allows my fan to bang against my fan shroud on right turns.

0 marks: 2-grade
3 marks: 5-grade
6 marks: 8-grade
stainless: ~5-grade

I'd go with either stainless or 5 grade. It's a bit more ductile than 8-grade, and will flex a bit with the movement of the mount due to cyclic loading. Just some Materials Engineering for the day.

Question on if going to build a block from ground up then how do you know what grade of bolt to use not having any thing there to start with in the first place? Does the motor mounts say any thing about what needs to be used?