Main bearings identification M54B30

[quakes]

Hi all,

I recently picked up a M54B30 crankshaft for a M50 stroker build, I do know that it’s probably more cost effective and easier to buy a S50 or S52. But they are hard to find here in Australia for a good price.

I was hoping someone could clear something up for me please? I have both green and what looks like yellow dots to mark the journal tolerances, I have been searching online and reading over the tis but I’m not clear on what main bearings to purchase if I have both yellow and green spots? Could someone please clear this up for me?



Thanks in advance.

[quakes]

Has anyone run into this before?

[nonturbodan]

The color classifications are not necessarily critical. I would order up whichever bearing shells allow the greatest clearance. If yellow is looser than green, I would order yellow.

Aftermarket shells are often sold in a standard size with no color classification. I have built bottom ends both ways, factory color coded shells and aftermarket non coded, they have all worked great. Doesn't have to be perfect. You can plastigauge them during assembly if you want to double check clearance but I think they'll almost certainly be fine.

[quakes]

Thanks so much nonturbodan. Appreciate the input. I’ll move forward with that.