260 cam
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2nd Gear
Joined: Jan 2018
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From: New Zealand
260 cam
Hi guys
Anyone running the se 260 cam? I have just finished a new 113ci build with se mva heads and a se 260 cam, pretty disappointed with the results, it feels completely gutless untill 3500rpm then wants to rip your arms off!!
what are everyone elses opinion on the 260? Should I change it out? If so what cam produces the best torque right up through the rpm?
Anyone running the se 260 cam? I have just finished a new 113ci build with se mva heads and a se 260 cam, pretty disappointed with the results, it feels completely gutless untill 3500rpm then wants to rip your arms off!!
what are everyone elses opinion on the 260? Should I change it out? If so what cam produces the best torque right up through the rpm?
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Joined: Mar 2010
Posts: 21,006
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From: Poolville
Okay, 150 psi is not static compression.. That is CCP (cold cranking pressure) which is actual cylinder pressure that is based on the IVC (intake valve closing timing in degrees). The later the closing time in degrees, the lower the ccp.
So please tell us "exactly" everything you done to your motor..
With a current ccp of 150 psi and an ivc of 55* in that SE 260 cam and a little reverse calculating I would say that your static compression is some where around 9.0:1.
So lets figure your motor first then your actual static compression. Then we can figure a proper cam to carry you through the rpm range without giving up too much on the bottom.....
Do you have the SE kit number?
So please tell us "exactly" everything you done to your motor..
With a current ccp of 150 psi and an ivc of 55* in that SE 260 cam and a little reverse calculating I would say that your static compression is some where around 9.0:1.
So lets figure your motor first then your actual static compression. Then we can figure a proper cam to carry you through the rpm range without giving up too much on the bottom.....
Do you have the SE kit number?
Last edited by 98hotrodfatboy; Mar 11, 2018 at 07:18 AM.
Seasoned HDF Member
Joined: Mar 2010
Posts: 21,006
Likes: 7,541
From: Poolville
I did a little more research and those MVA heads have a huge combustion chamber.... You can take them off and have them done or find a reasonable cam (35-38* ivc) that will bring up the compression. The only thing those heads will drive is maybe a bus.......
The problem many people run into is that cams like that don't turn on until late in the RPM band. When they do turn on, the heads have almost reached their max flow. Also, with the cams characteristics, airflow at low rpms isn't a very high velocity with heads with bigger valves and open exhaust (for lack of really getting into it).
So you wind up with a soft bottom end that transitions into a nice top end but where you really ride, it's soft - especially when riding 2 up. Smaller, less built engines will actually run circles around it in the lower to mid rpms.
You will get a much more fun and streetable ride from a cam/head/exhaust combination that is matched for a realistic power band - where you will ride 99% of the time vs a max HP#.
So you wind up with a soft bottom end that transitions into a nice top end but where you really ride, it's soft - especially when riding 2 up. Smaller, less built engines will actually run circles around it in the lower to mid rpms.
You will get a much more fun and streetable ride from a cam/head/exhaust combination that is matched for a realistic power band - where you will ride 99% of the time vs a max HP#.
Last edited by Ed Ramberger; Mar 12, 2018 at 05:55 PM.
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