| Many people view cams as a commodity. One cam from this company is just as good as another from another company, right? Wrong! There is a dirty little secret floating around that many people don’t know. There are a number of companies, notable companies, that have based their businesses on copying other people’s cam profiles. These people will take a design, measure it, and reproduce it as their own work. Then they may take a design and apply it to applications where the original designer never intended it to be used. This process can happen multiple times, over and over, and the design data is heavily degraded each time a copy job is done. You as the consumer, may never know if your cam contains a grind with the original design or a knockoff of someone else’s work. After all, it measures as the duration on the cam card (I would hope!). The effect of copied cams is to increase bad valvetrain dynamics and loads in the system. Think of that old form in the office where the original has been lost, and you now have a copy of a copy of a copy. It’s hard to read isn’t it? The same process happens on cams, but only after a couple of copies. Another pro tip is to ask for an inspection report on your cam. The best measurement machines for this are made by Adcole, but there are other machines (Marposs, Jenoptik, etc.). While this won’t tell you if the design is any good, it will tell you if it was ground reasonably accurately. A good cam will be 0.002″ from the design data during the lift event, and seven tenths of a thousandth of an inch from the design data during the base circle. My advice as a cam designer myself is the following: |
- Make sure you’re doing business with the company doing the original work.
- Ask to speak with the cam designer. They aren’t on the phone often and would love to talk to you!
- Ask him what year that the design was produced. Many cam companies are still selling the grinds they designed in MS-DOS back in 1984. You remember that the Corvette ran 0-60 in 7.1s in 1984, right? Go with a more modern design
- Ask what journal size the profile was designed for. BBC size is 1.948″. Sometimes SBC grinds are repurposed for BBC cams, leaving performance on the table.
- Review the inspection data to see how well the cam was ground. Ask that the profile error plots be included in the report. I’d be glad to review any Adcole reports for those unfamiliar with interpreting them.
