Hello colleagues, I have a case study and I am asking for help... It is about Audi A4 B9 2017 3.0tdi 272hp. I decided to service the engine properly, camshafts, chains, connecting rods and main bearings all OEM plus new bolts. There was no problem with all the parts except the main bearings and this is where the need for help comes in. No one knows which bearings to order, no one knows what color the car left the factory, some say they measure the shaft, others say they measure the bearings, others say they measure the clearance between the shaft and the bearing, and now once a week we can't order these bearings. What I found out is that they originally come in 4 colors and opposite each one there are dimensions but are they mm or clearance. No one tells or knows what we should look at, what we should measure and how and how to navigate which bearings to order. ... Please advise and help thanks Good night

 

 

 

Boris.

Have you ground the crankshaft journals to smaller dimensions? In practice it is difficult to measure either the clearance or the bearing accurately, however one can accurately measure the journal diameter with a micrometer. I suggest you tell Audi what journal size you are dealing with and let Audi worry about the colour.

Hello Boris,

I agree with Clifford - keep it simple.
It may also be worth having your current shell width measurements - in case asked for. 
The only other measurement you can do is to clamp the end cap onto the conrod, and accurately measure the internal diameter of the conrod, in case there are conrod differences from one engine batch to another. This dimension, and the crankshaft dimension would dictate the thickness of the shell bearing. 

Kind regards,

Gareth.