How do the rollers on roller cam lifters get oiled? I've purchased retro-fit, hydraulic roller lifters from Erson (SL-541) and don't understand how they are lubricated.

 

The same way the cam to lifter interface does on a flat tappet, from the lifter bores and splash.

 

If your car is an automatic transmission, then check the torque converter bolts for looseness. This can cause a knocking sound similat to a spun rod bearing. Also check your belt driven accessories to make sure your pulleys are tight.