Boom wrote:
why do you plug the oil galley?
also the lifter bushings are needed why? different diameter lifters? roller lifters? the only reason I would see a need for bushing would be diameter size, does a bigger cam put stress on the lifters bore?
Good questions Doug.
The oil galley that a stock pump outputs to is plugged because it is going to be full flowed. When it's full flowed the oil from the pump comes out through the pump cover, goes to a filter and possibly a remote oil cooler, and then returns to the case to the same channel that I am plugging there, but a couple inches away. The reason for plugging that hole in the case is to prevent any pressurized oil from traveling down that galley and escaping between the case and the pump. The outlet to the pump is also plugged for the same reason.
The bushings are needed to prevent wear of the lifter bores. The lift at the cam on the custom cam I'm using is like .415". With that much cam lift the lifter places a lot of force and hence friction on the lifter bore. With a soft material like magnesium, the lifter bores will wear out quickly and become oval, causing a loss of oil pressure and a lot of magnesium wear particles in the oil. The bronze bushings are far more wear resistant and solve the problem. The aftermarket aluminum cases like I run don't have that problem because the AL is a lot harder.