Why are hydraulic roller lifters, different on different sides in the engines?
Just wondering, how can that be?
Look at where/how the oil flows to get to each side:
- Passenger side oil comes straight up the back from the oil filter in a large passage about 7/16" diameter IIRC.
- Driver's side oil has to flow from the far (front) end of the passenger side gallery, which is the lowest pressure point in that gallery, down the small passage (3/16" diameter IIRC) to the #1 main, then across the main bearing area (another possible restriction), and back up another small passage to the front end of the driver's side gallery. And at the #1 main, some oil splits off to the #1 cam bearing, so there is more flow exiting from that area to cause pressure loss. All the driver's side flow has to go a lot farther and through smaller passages; if the lifter flow (through and around) is more, it just gets worse. (Hence the need to pay attention to lifter bore wear and the clearance.)
You can't flow fluid across that path between the front of the passenger side to the driver's side via the small, longish feed passages without some pressure loss. The driver's side is simply further downstream in the system.
I think everyone's ideas exclusive of this difference, are the reasons the OP saw his different lifter designs.
