Advancements in camshaft grinding technologies have improved the surfacefinish on the lobe
As the money and competition in the Nextel Cup Series have skyrocketedin recent years, the image of a Nextel Cup engine builder has changed.The old mechanic who learned about engines working in his daddy's garageis still there, but working right alongside him is a mechanical engineerwho spent his youth studying the laws of thermodynamics. It's adifferent world from the old days (Maurice Petty told us once that heused to scrounge junkyards looking for parts for Richard Petty's cars),but that's OK because that's what is needed to continue the pace ofinnovation.
Much of that innovation, however, doesn't come from insidethe engine shop but from outside sources. Many of the advancements inrace engine technology actually come from the parts manufacturersworking closely with the race teams to give them what they need. That'sthe good news for a Saturday night racer. After all, the last thing aNextel Cup team wants to do is pass along its discoveries to anyoneelse, but an innovative parts manufacturer can take what it learnsracing on the Nextel Cup level and use that knowledge to help everyonego a little faster.
To find out more about how high-end racing affectsthe little guy, we called up the folks at Comp Cams and asked afew personal questions. Comp Cams is a perfect example of thisphenomenon because the company produces a wide range of engine parts andis a big player in everything from Nextel Cup, to drag racing, toSaturday night stock cars, all the way to go-karts. Interestingly,there's a lot more going on than we originally thought.
Super-precise measurement equipment such as this Adcole machine allowscam grinding technic
"When it comes to the camshafts, the demands of theNextel Cup and Indy Car teams that we work with required us to go togreat lengths to meet their specs," says Chris Brown, Comp's vicepresident of operations. "But once we figured out how to meet theirrequirements, it was relatively easy to continue those improvements toour other cams.
"The number one thing that we've done is have ourcamshaft design team work with every type of engine out there. We've gotthree cam designers, and instead of having them specialize in certaintypes of engines, they all work on everything from Nextel Cup, to TopFuel drag racing, to street cars, to oval track stock car racing. Theyeven do the cams for go-kart racing. That's really paid off for usbecause of the depth of knowledge that those guys have acquired. Theyunderstand what's happening inside an engine a lot more than somebodywho only has access to one style of engine. So now when they encounter aproblem for a Saturday night race engine, they can draw on theirexperiences with how drag racers or Nextel Cup racers solved a similarproblem.
"The upper-level guys are always raising the specs that theyneed for their products. That's why we acquired an Adcole machine thatchecks cam tolerances. But what happened was our guys on the manual camgrinders started using it to tune up their machines and methods for alltheir stuff. In the past couple of years, they have gone from having awindow on their duration specs from 0.5 to 0.75 of a degree down to 0.2to 0.25. Without having to tell them, their own pride in theirworkmanship has brought them down that path.
Advancements, including holes that feed pressurized oil to the needlebearings and tool ste
"We've also learned a lotabout surface finishes, what works best on a roller (cam) and what worksbest on a flat tappet. We've taken what we've learned frommicropolishing and used it to test different types of grinding stones sothat the stone itself leaves a different finish on the cam lobes. That'shelped us improve the lobe surface finish for guys that don't want to orcannot pay for micropolishing. All that stuff is directly related tosome of the high-end cams we have done for NASCAR teams because theyoften put a spec on the surface finish.
"Something that's prettyinteresting is one of the biggest advancements for the racer running aflat tappet cam didn't come from the NASCAR guys, but from working withan Indy Car team. When we first started working with Toyota's Indy Carprogram a few years ago, they said the cams had to be nitrided. And wesaid, '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 alsohelpful in just about any flat tappet application. We're doing it on allour overhead cams, and it's made a big difference in the cams for the2300cc Ford motors. Those cams for the four-cylinder motors we used tocall boomerang cams because you could count on three out of four comingback. 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 wentfrom 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 theV-8 stuff, too."
Comp's engineers say that using lifters that restrict the movement ofthe pushrod seat can
"Over the years we had two types of solid roller lifters--let'scall them better and best," Brown continues. "The NASCAR Busch and Truckteams used the 'best' lifters and the Saturday night racers used the'better' lifters. But the advantages of the best lifters have bled downuntil there's really not much difference between the two. There's no onebig thing that you can point to. It's really just different things welearned and applied to other lifters. These are things like changing thesize of the needle bearings in the roller to reduce the load on them,drilling oil holes in the body that inject pressurized oil directly intothe bearing assembly, and making the axles of tool steel rather thanmild steel. It's just a lot of little things that add up to make thelifter a more durable part with a longer life.
"The same thing hashappened with the hydraulic roller lifters. A lot of the road racers anddrag racers have to use them, and what we've learned there can be reallyhelpful to the Street Stock-type racer that is required to use astock-type hydraulic lifter. We've learned that by controlling thepushrod seat location in those things, we can get a lot better valvecontrol. We've gone from a tappet that maxed out at 6,000 rpm justbecause things got so out of control, to stuff we now are running at7,200 rpm. We restrict the amount of movement the pushrod seat hasinside the lifter. What that does is prevent it from depressing too farand getting enough hydraulic pressure behind it that it would expand thelocation of the pushrod seat, which would hold the valve open a littlelonger."