What We Like: It's easy to set up and fits under the stock timing cover. We found that the gears set up with minimal lash and lined up with each other perfectly in our application.
What We Don't: Conceptually, we were a little wary of floating intermediate gears in a precision system. However, when the system was put to the test, it seems as though it works, and it's hard to argue with that.
Noise: The C.A.T. standard dual-idler geardrive we tested turned out to be far less noisy than we were expecting, producing just the mellow hum you'd get with any straight-cut gears. Besides the standard geardrive sets, C.A.T. also sells a noisy version for most applications under another part number, presumably for those enthusiasts who want to be heard as well as seen.
PN/Price: GD440, $118.90 (fastengineparts.com)
Source: C.A.T. Power Engine Parts; Baldwin Park, CA; 626/330-1999; catpep.com
Jesel Belt DriveHow It Works: The Jesel drive uses a toothed drivebelt and pulley set to drive the cam. A Jesel setup features a custom cover, adapters, and seals that place the cam drive externally.
How It Goes On: Since the Jesel drive is external, the front cover is recessed to fit behind the drive rather than over the top of it like a conventional timing cover. Each cover is designed for the specific block type, however some block clearancing is required in most applications. On our 440 Mopar block, some clearancing was required at the front of the block, a job we took care of by hand with a carbide in a die grinder. Once the cover is installed, the crank pulley is driven in place. At the cam, the thrust shim pack is determined and set, and the pulley components bolt in place. Line up the timing marks, slip the belt in place with the upper pulley loose on the spider, then tighten it up. We found that the stock-type water pump and damper bolted on and cleared with no problem once the Jesel was installed.
What We Like: The fast and accurate cam timing adjustment allows us to really dial in an engine for maximum power. The well-engineered thrust control was impressive, and we appreciated that everything fit together precisely, allowing the system to bolt together quickly once the block was clearanced. The high-tech-racing looks are a bonus.
What We Don't: An external drive wouldn't be the best choice in a daily driver street application, since it is vulnerable to dirt and debris. It's not for the budget-minded, either.
Noise: We didn't hear it make a whisper on the dyno.
PN/Price: KBD-35000, $805.00 (hensleyperformance.com)
Source: Jesel; Lakewood, NJ; 732/901-1800; jesel.com
Car Craft Dyno-TestWe put the various cam drive systems against the pump to find out for ourselves if any make a wild difference in power. Before the dyno day, we took the time to dial in each system, degreeing each to an accuracy of a quarter of a degree, setting the installed intake centerline of our custom Competition Cams' solid roller to 103 degrees after TDC.
The peak numbers listed are the average peak results. The average power figures listed cover 3,100-6,600 rpm and are the results of averaging the average numbers from the same three pulls the peak numbers were derived from.
As can be seen from the average power results, the four drive systems tested showed less than 1 lb-ft of torque and 1 hp in variation of power-a difference of less than two-tenths of a percent.
Cam-Drive Dyno ResultsTested at Westech Performance GroupSuperFlow 902 engine dynoAll drives at 103 installed centerlineAverages calculated from 3,100-6,600 rpm