There's a large groove all the way around the middle for oil to come in. If there was no oil getting to them, they never would have pumped up and it would sound like a typewriter ready to fly apart.
Also, the lobes on the camshaft are tapered to one side to make the lifters rotate while in operation. That prevents a wear spot from forming on the rubbing surface. What IS important is you must reinstall the lifters back on the lobes they were on before because they will have matched wear patterns. Switching lifter locations can lead to excessive wear of the bottom of the lifter and the cam lobe.
Sunday, July 8th, 2012 AT 5:32 AM