When are Titanium Retainers Needed?

“These days, almost never,” proclaims Billy Godbold, Comp Performance Group Valvetrain Engineering Group Manager. For sure, anytime you can reduce the mass of the valves, valvesprings, valve locks, and retainers, it’s a good thing. Dynamic forces seen at the valve increase with the square of the rpm, so the higher the rpm, the more important it is to cut valvetrain mass without reducing reliability. “The crossover point where saving valvetrain weight becomes significant is around 6,000 rpm,” Godbold says. “Lightweight retainers alone can add 100–200 rpm to the powerband.”

The problem with titanium is it begins to wear as soon as it’s installed. Wear increases the valvespring’s installed height, resulting in a loss of dampening over the nose of the cam. On the high end, a titanium retainer may actually wear out faster than the valvespring. That’s why today’s wear-resistant tool steel is the preferred retainer for most applications. Only several grams heavier than an equivalent titanium retainer, it’s still nearly 30-percent lighter than the 4000-series steels used to make “standard retainers.” Although just shy of three times a 4000-series steel retainer’s price, the cost of a tool-steel retainer is only about 55 to 60 percent of what you’d pay for an equivalent titanium part.

At the extreme high end—NASCAR cup racing and Pro Stock drags—”ultimate” retainers  are now made from maraging steel on a custom-order basis. But get out your wallet: A 1-inch maraging-steel bar is about $120, and that’s before forming! A full 16-piece set of maraging-steel retainers might go for as much as $1,200. Concludes Godbold, “About the only remaining ‘best use’ for titanium retainers would be in a bracket-race, triple-spring application—that’s the one instance where tool-steel’s weight starts to go up.”

Contacts

Comp Cams; Memphis
901.795.2400
CompCams.com

Summit Racing Equipment
330.630.0240
SummitRacing.com

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