Beehive springs were originally...
Beehive springs were originally created for restrictor-plate racing, but the design is so successful that it has made its way to over-the-road automobiles. The varying diameter of the coils makes the spring resistant to harmonic failures, and the small diameter of the top coil means a smaller retainer can be used. Currently, these springs may be suitable in Street Stock-level cars where OEM parts are required, but Comp Cams representatives say it won't be long until ovate wire beehive springs are capable of functioning with the high-lift racing cams in Saturday night engines.
"Something that's pretty interesting is one of the biggest advancements for the racer running a flat tappet cam didn't come from the NASCAR guys, but from working with an Indy Car team. When we first started working with Toyota's Indy Car program a few years ago, they said the cams had to be nitrided. And we said, 'What's nitriding?'
"Nitriding improves the cam's surface finish, and as it turns out, it's not just good for Indy Car racing-it's also helpful in just about any flat tappet application. We're doing it on all our overhead cams, and it's made a big difference in the cams for the 2300cc Ford motors. Those cams for the four-cylinder motors we used to call boomerang cams because you could count on three out of four coming back. So much on those heads has to be just right or the cam will fail. It isn't the cam's fault, but that's what usually got the blame. Anyway, to make a long story short, we started nitriding the 2300 cams and went from a 70 percent failure rate to a 2 percent failure rate in two years. The difference is just incredible, and it can be just as helpful in the V-8 stuff, too."
Lifters "Over the years we had two types of solid roller lifters-let's call them better and best," Brown continues. "The NASCAR Busch and Truck teams used the 'best' lifters and the Saturday night racers used the 'better' lifters. But the advantages of the best lifters have bled down until there's really not much difference between the two. There's no one big thing that you can point to. It's really just different things we learned and applied to other lifters. These are things like changing the size of the needle bearings in the roller to reduce the load on them, drilling oil holes in the body that inject pressurized oil directly into the bearing assembly, and making the axles of tool steel rather than mild steel. It's just a lot of little things that add up to make the lifter a more durable part with a longer life.
Advancements, including holes...
Advancements, including holes that feed pressurized oil to the needle bearings and tool steel axles, have filtered down from NASCAR Busch Series racing to make even budget roller lifters more efficient and durable.
"The same thing has happened with the hydraulic roller lifters. A lot of the road racers and drag racers have to use them, and what we've learned there can be really helpful to the Street Stock-type racer that is required to use a stock-type hydraulic lifter. We've learned that by controlling the pushrod seat location in those things, we can get a lot better valve control. We've gone from a tappet that maxed out at 6,000 rpm just because things got so out of control, to stuff we now are running at 7,200 rpm. We restrict the amount of movement the pushrod seat has inside the lifter. What that does is prevent it from depressing too far and getting enough hydraulic pressure behind it that it would expand the location of the pushrod seat, which would hold the valve open a little longer."
Pushrods "Pushrods are no longer simply pencil-sized metal rods," asserts Brown. "Now they are available in a variety of diameters and shapes with different wall thicknesses. That's because we've learned that pushrods are important for controlling harmonics as well as simply providing a connection between the lifter and the rocker arm. All that stuff is directly related from extensive spintron testing. For example, the LS1 engine from the factory has a terrible problem with bending the pushrods if you over-rev it. Well, just by going from the factory pushrods to a one-piece pushrod with an 0.080 wall thickness, we've eliminated those issues and gained about 500-700 (rpm) on the redline. The same thing is going on in race engines where you can add a little weight to the pushrods and still gain a lot because you are getting rid of the bending and limiting the harmonics. As little as five years ago, racers were running 51/416-inch-diameter, 0.080 wall pushrods, and now they are using 71/416-inch-diameter pushrods. It looks like a Lincoln log in there, but it works."