Thread: Piper Camshafts
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Old 04-30-2016, 09:36 AM   #77
Tim Radley
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Quote:
Originally Posted by Blokatos View Post
Well, this is not as accurate as it should be. A 13 mm cam will always bring the valve closer to the piston, all else being equal. Ramp rates and duration play a role to the relation the valve has with its seat, not with the piston.
Sorry but that is just not the case. Piston to valve clearance is tightest at lower lift not higher lift. At max valve lift the piston is more than half way down the bore. A 13mm lift with 240 duration will likely have a lot more piston to valve clearance than an 11mm lift with 280 duration. Adding 1mm of lift to a cam profile doesn't mean you need 1mm deeper pockets cutting in the pistons.
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