Part 3 wraps up our investigation of why parts fail and how to prevent mishaps.
The cryogenic process lowers the temperature of the parts to 300°F below zero. Increasingly, machine shops are taking advantage of cryogenics to dimensionally stabilize their parts. They have found that by removing the internal stresses, components retain their exact shape. In addition, the cryogenics process invests the part with longevity—it increases tool, gear and part life.
If the part’s initial heat treatment is correctly applied, its hardness will remain unchanged. The toughness, however—its fatigue life—will increase. On the other hand, if the heat treatment was executed improperly, cryogenics will complete the process and increase its hardness. Therefore, it’s important to record hardness before cryogenics is applied.
After cryogenics the components are rechecked for hardness. Those that are too hard for their specific purpose are tempered to the proper hardness. The desired hardness varies with each component and its application. For example, street, drag race and road race transmissions are each hardened to different values. Finally, after tempering they are subjected to a second cryogenic process to remove any residual effects induced by the tempering process.
These processes are exploited to their fullest potential during transmission upgrades. Liberty’s Gears upgrades about 1,500 to 2,000 Tremec transmissions yearly. “These particular transmissions are extremely strong. In fact, they possess a capacity that ninety percent of their users will never explore,” says Craig Liberty.
So, for budget-minded racers and enthusiasts who don’t have the inclination to spend three times more than necessary, a simple metal-enhancement program might be a revelation. In braking systems, drivetrains, valvetrains, shocks, pumps and gears, it can significantly increase performance and longevity.
Liberty’s Gears shop gives the appearance of an Aladdin’s cave. From intricate parts for aerospace exploration to Honda bellhousings, and from one-off projects like a new Bonneville seven-speed gearbox for the Poteet & Main Speed Demon to metal enhancements, the place is bursting with activity.
Text by Sam Logan
Photos by Moore Good Ink