[30FF_]

Hey guys I'm rebuilding my n54 engine that had rod knock I'm currently putting the rods and pistons back in the cylinders and I tightened the rods down with new acl standard size bearings along with new bolts and they wiggle side to side as you guys can see in the video posted. I already checked the journal diameter which within spec of the 49.9 basically 50mm and also check the rod ID bore and it is 53.6 don't know what to do know and I'm completely dumb founded I have also double checked that the bearings are standard size and lower and uppers are in the correct caps.

Any information would help

[Foghorn]

Side clearance on the connecting rod big end is a must, you need to find the side clearance value and measure it if you’re concerned.

[30FF_]

Originally Posted by Foghorn

Side clearance on the connecting rod big end is a must, you need to find the side clearance value and measure it if you’re concerned.

Thank you will do even tho these specs seem to be no where

[Foghorn]

Unless there are signs of unusual wear on the sides of the connecting rods and cheeks of the crankshaft journal then it’s unlikely you need to be concerned.

The side to side movement of the rods in your video are normal. I don’t have the N54 specs but side clearance of 0.020” or more is typical.

[Foghorn]

You didn’t mention if you Plastiguaged each rod bearing, you did say you measured diameters, but Plastiguage tells you the sum of all the parts.

Of course you need to be sure you matched the connecting rods and caps as well as the orientation. Are you using any new parts other than bearings and bolts?

I also installed standard size ACL bearings with the updated BMW rod bolts. In my case the crankshaft journals were all the same size (“r”) and each one Plastiguaged at 0.018”. There was side clearance once assembled with lube.

[feuer]

Look normal to me. Not only n45 but all engines will have side play.

[B58]

Normal. If it does not have side to side play then you have a problem, but I'm not sure what the spec is on the N54.

[IllSic_Design]

normal, same as mine when I did rod bearings