Isky Racing Cams, a name synonymous with high-performance since the beginning of high-performance, recently released its new line of heavy-duty HPX hydraulic roller lifters. “Now that there are so many hydraulic applications, people are rebuilding the engines with hydraulic lifters when going to a high performance application, instead of just converting to solids,” says Isky’s Nolan Jamora. “When you start getting aggressive–especially turbocharging or supercharging the engine–it’s killing the OEM hydraulic lifters. They just can’t take it.”
To that end, the two levels of Isky Racing Cams HPX series of hydraulic roller lifters–Silver and Gold–are designed to combat the weaknesses found in OEM and OEM-style hydraulic lifters. “The Silver version is a needle-bearing version of the lifter, while the Gold is an upgrade to the EZ-Roll solid bushing with no needles,” Jamora says. “The major difference between the two is that the life expectancy of the solid bushing is four times that of the needle bearings.”
Isky has coined the term “Big Foot Effect” to describe why the solid bushing has better wear characteristics than the needle bearing version. “When you are running on needle rollers, you are only putting pressure on three needles at a time,’ says Jamora. “With a bushing, you are running on a bed of oil, and what happens is that the load is spread about 350-percent more than with the needles. You’re running on hydraulic pressure, so there’s no metal-to-metal contact.”
Thanks to the specialized internal valving in the HPX lifters, they are designed to substantially exceed traditional hydraulic roller lifter limits. “A normal hydraulic roller lifter can only take about 130 pounds of seat pressure, and 350 pounds of pressure open. These HPX lifters can take 200 pounds of seat pressure and 550 pounds open,” says Jamora. “They don’t bleed down like a normal lifter, either. They are all short-travel designs, which means not only do they not compress under high spring loads, but they work up to 7,500 rpm and with high ramp rates, as well.”