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Another note, the new springs seemed to have an oval shape to them making for interference if not aligned, I had checked on installation with the original springs to see if they were oval, the one I looked at seemed so, but now that I checked a few more I'm not sure if the old springs aren't more circular, in which case there would be no contact between inner and outer I assume.
**** (EDIT: Removed a spring pair again to check for squareness and measured the circumference, new and old springs are not oval, at least for the purpose of contact between the inner and outer springs. Oval was a visual or optical illusion and contact between outer and inner springs most likely was just the way the springs were sitting, but don't know for sure. They were around 1/16 " out of square and I may have aligned the inner and outer springs to have their deviation from square characteristics in the same locations, may not be the right thing to do.)***
I've also heard of harmonics, how does one explain this? Do the eigenvalues of the two springs in our engines appear so close that the need for damping is required? I don't know how that would happen exactly, but I'd think it would require more precise spring tolerances then I saw so that a known contact point/points are guaranteed between inner and outer springs.
Phil
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Last edited by ahh911; 08-10- at
06:02 AM
..I crudely measured the installed height, with a ruler. I have also ordered a valvespring micrometer. It looks to be 47.5 mm or 1.87". If I understand correctly, with a 1.175" bind height and .587/.597" net lift, that means I should have .098" before bind on the exhaust and .108" before bind on the intake. Both intake and exhaust looked about the same at approximately 1.87" height.Barry_R wrote:You really need to check installed height on those.
I just did a really quick look at the spring data (using Summit's site - it was aready open on my 'puter). If you were assembled at the Ford spec height of 1.82 you were only .048-.058 from bind based on your net lift number. If the retainer had the normal +.100 inner step on it that thing was likely hitting bind even after accounting for reduced lift from deflection and such. Look at the unbroken ones for signs of coil to coil contact.
Other wise I'd say it's just a matter of fatigue failure or heat. If it's fatigue you'll need a better spring - only a metals guy with the broken part in hand can tell you. If they're getting hot the inners are smaller in cross section and will get hurt first.
I crudely measured the installed height, with a ruler. I have also ordered a valvespring micrometer. It looks to be 47.5 mm or 1.87". If I understand correctly, with a 1.175" bind height and .587/.597" net lift, that means I should have .098" before bind on the exhaust and .108" before bind on the intake. Both intake and exhaust looked about the same at approximately 1.87" height.The retainers do have an inner step that the inner spring rides on. It is about .1" With .098" exhaust and .108" intake clearance does that mean my inner springs are binding????If so why wouldn't crane advertise the coil bind height taking into account that the inner spring typically is installed at .1" shorter height than the outer?I also talked to Crane. They want me to send them the valvesprings for inspection. They seem confident that they can tell the cause of breakage by examining the springs. They said they would replace depending on what they found.I pulled one inner spring out and looked at it. I couldn't see any obvious sign of coil to coil contact. I'm not sure If I would know what I as looking at though.paulie
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