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12-08-2018, 12:30 AM
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#1 |
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Senior Member
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math class needed on valve springs
what is the math formula for a known spring rate to calculate seat and open pressure ?
spring rate is 370lbs @ 1.00" closed valve spring installed heigh1.780 open valve spring height 2.237 seat pressure ? open pressure ? thanks in advance |
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12-08-2018, 02:21 AM
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#2 |
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Re: math class needed on valve springs
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12-08-2018, 09:57 AM
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#3 | |
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Re: math class needed on valve springs
Quote:
370 rate x .543" lift = 200.91 lbs more than whatever you set/start with the installed height at. You have to have a baseline height/pressure to calculate from, which the spring chart or actual test pressure will provide. That height is a variable based on valve stem length, +/std./- locks & retainers, spring seat machine work, depth of valve job seats.
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LOCOMOTION Racing Last edited by Myron Piatek; 12-08-2018 at 10:03 AM. |
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12-08-2018, 11:00 AM
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#4 |
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Banned
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Re: math class needed on valve springs
If you can afford it, this is the cats meow..............
 https://www.summitracing.com/parts/l...+5ba26a96cdb6b Wish I had it years ago! |
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12-08-2018, 01:43 PM
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#5 |
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Senior Member
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Re: math class needed on valve springs
What is the valve lift on the int. and exh.?. gsa612
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12-08-2018, 04:59 PM
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#6 |
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Re: math class needed on valve springs
If you can find a comparable spring on the PAC Racing site, this link to their spring rate calculator might help.
https://www.racingsprings.com/index..../?sku=PAC-1224 Edit: Change the part number to your match.
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Dale Shearon 68 Mustang 6394 |
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12-08-2018, 06:08 PM
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#7 |
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Senior Member
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Location: Southeast Michigan
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Re: math class needed on valve springs
The basic formula is F=kX . F is the force , k is the rate , X is the difference in spring height from the length of the spring when it is not loaded .
Last edited by ss3011; 12-08-2018 at 06:09 PM. Reason: Clarify |
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12-09-2018, 11:47 AM
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#8 | |
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Location: Pittsburgh
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Re: math class needed on valve springs
Quote:
To add to above, the spring rate is stated as the force generated per unit of compression. Ex: 1,000 Lbf/Inch, 1,700 N/cm etc. Also, its spring FORCE, not pressure. Spring pressure is a common misnomer racers seem to always use, and it just wont die. Its entirely wrong. Its not a pressure, Its a force. |
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12-09-2018, 10:11 PM
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#9 | |
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Senior Member
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Re: math class needed on valve springs
Quote:
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12-10-2018, 10:09 PM
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#10 |
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Senior Member
Join Date: Jan 2008
Location: 100th Meridian
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Re: math class needed on valve springs
The Pac 1220X spring shows 160 lbs seat press.at 1.900 and 400 lbs open at 1.250 which is close to coil bind.If you subtract your lift of .450 from the 1.900 your at 1.450 open.That may give you only 360lbs press.You need to find a "short" spring with your low lift that will give you the open pressure your looking for.Even if you do find a long spring that gives you the numbers, but is .300+ from coil bind your going to have valve stability issues. Have you looked into Comp cams ?. gsa612
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