.650 double springs too much for this cam?
12-18-2008, 06:35 PM
#23
They were not testing power output, but rather the impact of valve spring load on a hydraulic roller lifter. Concerning what was measured, what you state could have been measured but not included in the test summary. Stating it wasn't measured is an ASSUMPTION.
This was a data point to help illustrate to the OP the valve springs he is proposing will not collapse a hydraulic roller lifter.
This was a data point to help illustrate to the OP the valve springs he is proposing will not collapse a hydraulic roller lifter.
B)That Crane test was a Crane billet lifter for a Big Block Chevy with a completely different rocker arm at a relatively lower RPM. The test was on a Crane lifter. The OP has stock LS1 lifters. I wouldn't assume that a stock OE ls1 lifter can hold under the same loads as an aftermarket billet lifter without collapsing.
Doesn't mean it's bad either. I have a street car/weekend warrior, not a race car campaigned at national competitive events. I do frequent the road course for HPDE's where I spin the engine to 6800 RPM. I have never had an engine related issue in 71,xxx miles since the car was new. Approximately 60,xxx miles of the 71,xxx were with the Crane rockers and Crane 144833-16 valve springs.
Pushing the power envelope will cause one to discover the flaw in any part or design that's substandard for the task, agreed. We can discuss theory all day long, but what I have used/experienced has shown no flaw in the Crane rocker design. Can you cite any specific cases where this product was proven faulty, specifically contributable to the 'quick lift' design?
Physics and basic mathmatics makes it bad.
Putting peak ratio, and therefore peak acceleration and load, at the moments leading up to the valve closing is BAD. With stock valvetrain components, it's probably not enough to cause problems...even at brief moments at 6800 RPM, but more lift and faster ramp rates will lead to problems SOONER than "proper" geometry. It will prove substandard for a task that "proper" geometry could handle. I would bet a LOT of money, with a "competition" valvejob where the seat cut is taken to the edge, those OEM valve heads would tulip like a toilet plunger.
BTW, what are you expecting to see as an indicator of a flaw? What issues would you expect to have? Are you expecting some kind of catastrophic failure, or a "ticking", or whatever? If so, you may have an issue and not even know it. Have you compared the power output with other rockers, in a solid A-B-A test? Do you know for a fact that you aren't losing power to excessive valve bounce? I haven't seen any direct tests to prove me right or wrong, but maybe you could be the first...
