Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - Broken inner Valve springs Dart Iron Eagle SS Heads on Chevy 383 Stroker
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Old 12-29-2012, 09:41 AM
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It appears that the spring pocket (seat) is too large O.D. for the valve springs. That allows the springs to dance on the seats. If you have a damper, dancing will cause the damper to fail first, then the valve springs themselves. It appears the spring seats may be machined 1.500" O.D. That needs to be verified before you order a new set of valve springs. The spring seat O.D. should be .030" to .060" larger than the valve spring O.D.

If the seats are 1.500" O.D., install a set of Comp Cams 995 dual valve springs with dampers that are 1.437" O.D. along with the appropriate retainers. The larger O.D. outer valve springs will allow .030" - .060" clearance for the damper and inner valve spring to valve guide boss. The ledge on the O.D. of the valve spring seat serves to stabilize the valve springs. Sometimes hardened spring locators can be used but they are difficult to fit with the correct inner and outer clearances with the correct spring height. In order to use dual springs (with or without a damper) , you must use a larger diameter outer valve spring.
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