This year we cryo treated many crankshafts to help our customers. These customers had recently purchased crankshafts to help assure that they would not fail like their original ones did. After seeing so many crankshafts, it makes you wonder why they fail. After a little research, it became apparent why they fail. The two main reasons can be found below.
- The Wrong Crankshaft: A stock crankshaft is made for a car that is left in its stock state. When a racer decides to add more torque and horsepower to their application, they put more stress on the stock crankshaft. Some stock crankshafts can handle some added power, but most cannot. There are many ways to solve this problem. One is to purchase a stronger crankshaft that is made to deal with the extra stress of higher horsepower and torque. Another is to take the stock or aftermarket crankshaft and cryo treat it to remove residual internal stresses that can contribute to crank failure. Other alternatives include the application of surface coatings.
- Flawed Vibration Dampers: Stock dampers tend to have moving parts. For example, some crankshaft dampers have hydraulic oil in them. As the crankshaft rotates the fluid in the damper causes inertia. The end result is more stress on the crankshaft, which in time will lead to crank failure. Many aftermarket crankshaft manufacturers have found that lighter and smaller vibration dampers are better for racing applications. A small solid piece of rubber as a vibration damper is much better than one filled with hydraulic oil, because it will not cause inertia.
The bottom line is if you are going to add a ton of power to your engine, then you should expect a failure of your original stock crankshaft at some point. The way to ensure that a failure does not happen is to purchase a stronger crank or have your OEM or aftermarket crankshaft cryogenically treated. At the same time, if you are increasing power you should look for an aftermarket vibration damper that does not cause extra stress on the crankshaft. For more information about cryogenic treatment for racing components, take a look at http://www.nitrofreeze.com/racing.html.