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Tech Question
Wesley Johnson,, Winnipeg, MB, Canada, 1981 Dodge D150 318
Rick, my truck is currently stock except for a 4bbl,dual exhaust, and a MP .430/.450, 260/268 cam. I am replacing the heads with a pair off of an E58 360 that I had rebuilt. I am going to reuse the stock springs(I checked them for squarness and they are all the same height) and I was wondering what installed height I should set them at? I've read that you can go to within .100" of coil bind and be safe, can I do that with these ones? Also what is the correct free height of these springs so I can tell if they are sagged or not. I don't know if this is important or not but they use a triple groove lock. I know that I should use the matching springs but funds don't allow that right know.
Thanks and keep up the good work!
Wes-
I'm goping to assume you mean the late-70s E-58. The earlier, '76-down (Duster, etc.) version, used the same springs as 340s.
First, as you asked, here's factory specs for the late E-58 springs: Pressure, valve on seat: 108-118 lbs (@1.66")Pressure, valve open: 186-200 lbs. (@1.25")
Installed height: 1.625 - 1.688"
There's no published free height specification. For good reason: pressure checking is the right way to test a spring.
Installing any spring at less than the manufacturer's recommended height dimension is done at your peril. (OK, maybe 0.060" less is safe.) But there's more to the equation than simple coil bind! Without getting overly technical, I'll just asnswer your question with a question: How do you know that you aren't exceeding the wire's limit of elasticity when you do this? Answer: You don't!
These E-58 springs are about halfway between the old 340/360 hi-po springs, and the 360 2Bbl springs. Not really a bad choice. IF they were new. Valve springs are cheap. And they are one of the most highly stressed, and most often fatigued, parts in an engine. Do yourself, your heart, and your engine a favor: Cut out 2 greasy burgers a week for a month. Take the extra cash and buy a set of new, decent springs.
Rick
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