Determining Main Bearing Grades?

[Louis Rosanova]

>  1 1 1 1     <-- rod grades

This means you need grade 1 black for all four.

> 1 0 0 1 1    <-- crank main journal grades

You got half of it.

> But the numbers stamped on the block don't match what's
> in my FSM, it should be one letter followed by five
> numbers, what's there is this weirdness:

> U20 12      <-- supposed to be block main journal grades

Are you sure your looking in the right place. Its located near the fourth
piston.
Though you could always just figure it out using a micrometer or plastigage.

If you are looking in the right place and its just missing the 3rd number
than,

Bearing #1: D, Yellow  #2 A, Black  #3 Measure it  #4 C, Green #5 D, Yellow

So just measure the third one.  Or to be safe measure them all.

Louis Rosanova
95 200sx SE-R gots stuff