[HWYSTR455]

https://www.enginebuildermag.com/202...st-on-lifters/


"Oil Restrictors

Theoretically, with roller rockers and solid lifters, the valvetrain doesn’t need as much oil. Installing an oil restrictor limits the oil flow and reduces the windage from excess oil draining past the rotating assembly. It also keeps more oil flowing to the rod and main bearings. This is a specific application where some feel it improves performance.

The folks at Jesel point out that with the spring pressure and ratios being used in today’s racing engines, the lifters need as much oil to them as they can possibly get. They recommend plumbing the block, so oil is fed equally to the lifters through the front and rear of the oil galley, and in the event there is excessive oil to the top end, they recommend improving oil drain back to the pan through external scavenging lines or internal drains.

Restricting the oil flow to the lifters also limits oil flow to the cylinder heads. Since the oil cools the valve springs and other components, it’s not recommended to restrict oil flow. "


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