It is not necessary to oil your new bearings since they have never been used, but, it wouldn't be bad to oil them anyways.
they are oil bath, they get oil from the differential
YES, NEW cam bearings increase oil pressure and Improve oil lubrication through out the valvetrain. The cam bearings MUST be in GOOD shape if you want the engine to last.
engine bearings failed . do not run engine until bearings have been replaced. (note) count the bearings that came out in the oil and compare that number to the number on your new bearings. any bearings left in the engine can become failed with other parts and harm the engine. Some times, magnets will placed into oil filters.
NO Rear bearings are lubricated with the rear end / gear oil.
If the motor has oil ports you can put in a few drops of oil. If the motor has sealed bearings you will need to replace it.To fix a squeaky furnace, you need to add oil to the motor bearings. In some cases it could also be due to the fan, which would then need to be replaced.
Cam bearings, Main bearings, Rod bearings.
Low oil pressure due to: Defective oil pressure sensor Excessive engine wear (bearings, weak oil pump)
If the engine bearings are bad, then the oil pan will need to be removed to gain access. The engine will probably need to be removed and checked for other damage, as bad bearings can score the crankshaft requiring it to be turned smooth or replaced.
A spun cam bearing, or just bad cam bearings period. Push rods stoped up, Need cleaned.
Bearings help machines work smoothly and keep gears and machines that need bushings (with bearings in them) from wearing out too quickly. Bearings significantly reduce friction in working machines (with the help of a bit of oil and grease), thus reducing wear and tear--and reducing maintenance costs and times of repair.
The oil pump on supplies the oil to the bearings. The oil being squeezed by the bearings is what creates the pressure. If you are loosing then the bearings would be the problem.
Whatever type of motor oil you put in the engine, will lubricate the rod bearings along with all the other bearings and moving parts.