Cam LIft

What is the difference in the HP and torque that one cam will make to the other.
And how fast the bike will wind up.
And the life and durability of the engine and cam and componets.



And question 2

If you leave and go to a 590 to a 610 lift.

now you've gone to a High lift cam that required different cam springs.

What is the difference in the HP and torque that one cam will make to the other.
And how fast the bike will wind up.
And the life and durability of the engine and cam and componets.


And how much are you gonna have to worry about the quality of gas you will have to run.

O.K. Hotroadking waitin for a reply

Here is what somebody esle replied.

Aside from lift, cam duration probably has more impact on rideability and where the power is applied than any other cam characteristic. I found this understandable explanation of cam duration in my archives and am posting it for any that are considering a cam change. There are singel and dual profile cams but that should be a subject for another thread.

Duration has a marked affect on a cam's power band and drive-ability. Higher durations increase the top-end at the expense of the low end. A cam's "advertised duration" has been a popular sales tool, but to compare two different cams using these numbers is dicey because there's no set tappet rise for measuring advertised duration. Measuring duration at 0.053-inch tappet lift has become standard with most high-performance cams. Most engine builders feel that 0.053” duration is closely related to the RPM range where the engine makes it's best power. When comparing two cams, if both profiles rate the advertised duration at the same lift, the cam with the shorter advertised duration in comparison to the 0.053” duration has a more aggressive ramp. Providing it maintains stable valve motion, the aggressive profile yields better vacuum, increased responsiveness, a broader torque range, and drivability improvements because it effectively has the opening and closing points of a smaller cam combined with the area under the lift curve of a larger cam. Engines with significant airflow or compression restrictions like aggressive profiles. This is due to the increased signal that gets more of the charge through the restriction and/or the decreased seat timing that results in earlier intake closing and more cylinder pressure. Big cams with more duration and overlap allow octane-limited engines to run higher compression without detonating in the low to midrange. Conversely, running too big a cam, with too low a compression ratio leads to a sluggish response below 3,000 rpm. Follow the cam grinders recommendations on proper cam profile-to-compression ratio match-up.

Duration generally ranges from 220 degrees for a torquey bottom-end cam all the way to 295 degrees for a “top end rush,” typically measured at 0.053 inch lift.

As a general rule, lower-duration cams in the neighborhood of 210 to 200 degrees at 0.053 work best for stock-type replacement cams. Stepping past 220 degrees of duration (at 0.053) places the cam into the bolt-on, mid-range style category. These cams work well with the stock compression, intake and exhaust. Cams with 240-plus degrees of duration or more are beginning to step into the performance arena and generally work better with other induction, compression, and exhaust modifications. Duration has a marked affect on the cams power band and drivability.

Higher durations increase the top-end at the expense of the low end. As a general rule, cams with 220-235 degrees of duration tend to produce good low end torque. Cams with 235-250 degrees of duration tend to work best in the mid-ranges and cams over 260 degrees work best for top end power.

It is important to remember here that the duration values given are to be used as a general rule and that increasing the duration will have an effect on the idle characteristics and overall drivability.

Long duration, late intake closing cam designs are necessary to drag the last bit of power out of an engine. Unfortunately, these same cams can perform poorly under more normal riding conditions. In the quest for maximum power output, many (too many) Harley owners choose a late closing, high-rpm cam for their engine. The problem with such choices is that the engine seldom spends time in the rpm range favored by such cams.
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Good information. Thanks.