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Post by solo2racr on Jun 12, 2008 23:51:33 GMT -5
Out of all the mods I have done to my SR, the one thing that left is changing the cam. At the moment, the whole valve train is stock. The piston I am running is a Wiseco 90mm bore with 9:1 comp. What will be a drop in with this piston? I really don't care to have to cut deeper valve pockets. Spring, retainer, & valve changes are all good. A good torquey cam would be better than a high RPM cam. Probably from about 3000 rpm and up.
Thanks for the help,
Ken
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sven
Full Member
Posts: 166
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Post by sven on Jun 13, 2008 10:33:43 GMT -5
I'd suggest an "offroad-profile", i.e. not too much duration but higher
lift. These cams have good midrange to topend power and are easier
to tune in than roadracing cams which depend very much on proper
inlet/exhaust design. I've good experiences with mc251-30 and wb2,
but there are of course similar cams from other manufacturers.
Typical values could be:
lift .500" (not with stock springs, needs spring kit like R&D)
lift @tdc .16" (no deeper valve pockets necessary)
duration 275° @.04" (e.g. inlet 30°/65° exhaust 65°/30°)
Best regards
Sven
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Post by solo2racr on Jun 13, 2008 10:51:06 GMT -5
Great answer. Thanks Sven. one of the things I was wondering about (and you answered) was when they said "modified piston" if the Wiseco qualified. Even though the piston hasn't been touched, I was unsure whether the valve pockets were deeper than stock. Of course I would clay the chamber just to check. VERY bad finding out the hard way.
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Post by caferacercarl on Jun 21, 2008 18:55:16 GMT -5
like sven suggested, a cam with a retarded intake lobe centre from standard will pull harder around the 3 to 4,000rpm mark, no more than 300 degrees at zero and not more than 500thou at the valve, but you will need a valve spring kit, it may pay to read the rebuild article I wrote on these engines in the international magazine "VMX" issues 29,30 and 32. it tells all, FOR FREE !!!
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Post by hudriwudri on Aug 14, 2008 6:37:30 GMT -5
as sven said the mc 130 grind should be a prime choice or one of the webcam grinds as they all have somewaht similar overlap lift at tdc, if you wanna go really agro and have the motivation to go really agroo you could even pick the 180 and cut the pockets a lil deeper even tdc lift is semi harmless on that monster, nevertheless with the agressiveness of the profile and the involved issues you really have to take care about the rest of the valvetrain and springs to be used. Also the compression would have to be raised to bout 11:1, but the powergains will pay of outreageously  anyways lots fun with the interesting project  ciao and kind regards Christian |
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Post by solo2racr on Aug 14, 2008 11:11:27 GMT -5
it may pay to read the rebuild article I wrote on these engines in the international magazine "VMX" issues 29,30 and 32. it tells all, FOR FREE !!! I never could find the articles. Any ideas. |
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Post by alancase on Aug 15, 2008 0:33:57 GMT -5
PM me an email address or email me at alan@tec-solutions.com.au and I will send you a copy.
Regards
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Post by StewRoss on Aug 15, 2008 5:30:43 GMT -5
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