FEULING OIL PUMP CORP. Lifters Race Series® Twin Cam Oversized 4052ST

New revolutionary design with 0.115" of total travel vs. a full travel lifter with 0.200". These lifters will increase RPM by decreasing valve float and valve-train harmonics while maintaining a quiet engine. Travel reduction reduces the amount of oil that is required to fill the inside of the lifter which reduces oil aeration inside the lifter on steep, fast action high lift camshaft lobes. When oil aeration is present inside the lifter, the pushrod seat drops when the lifter rolls onto the front cam lobe ramp after squeezing the aeration down thus creating a noisy poor performing lifter. Short travel lifters should be set with 0.065" - 0.070" of pre-load and with the normal engine growth from heat will put the operating lifter pre load at or around half travel. Machined from a steel body and designed to exceed the needs of large lift camshafts and higher valve spring pressures with a slower bleed down rate. Compatible with either Feuling® HP+® or Race Series® oil pumps and are designed for use with both street and strip engines. Maintain proper oil flow to the top end, increase engine RPM, valve-train stability, decreasing valve float promoting maximum valve lift. Precision ground needle roller bearing with high chromium steel axle for long life and minimal friction. High-flow disc-style quick-reacting check valve for better reaction at higher RPM. Spin-Tron dyno developed and track proven. Made in the U.S.A.. Feuling® recommends pumping up each lifter by hand prior to installation, to remove all air and provide a fully pumped up lifter. Use of a thin weight oil like ATF in a squirt can works well.. Feuling® recommends Race Series® lifters for engines running higher than 185 lbs (84 kg) valve spring seat pressure.. Feuling® recommends the use of a high volume oil pump which will result in quieter, better performing lifters.