CAM Bearings?

[JTaylor2005]

Hi guys. This place is full of clever people so I thought I'd ask here.

On an aluminium head with aluminium cam caps. Are the bearing shells graded to fit the size of the hole that the cam is going into? That's if a bearing shell is even fitted? I am trying to understand all the tolerances etc and oil film thickness on head setups.

Thanks

[Rippthrough]

They usually just run in the carriers/caps with no bearing, the loads and speeds are much lower than the crank anyway.

[Ruan]

Yep, just run in the caps themselves, there's no bearing shell as such, just an oil port in the head side of the cap to provide forced lubrication to the bearing.