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Spring Pressure.


WHEELERBUFFY's Avatar
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04-01-04, 07:01 AM   #1  
Spring Pressure.

can anyone help me with a simple plan to build a spring tester to check pressure on springs for a 5 hp. go cart motor.
i know i can buy one but right now i can't afford this.
thanks for any advice on this project.

 
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04-01-04, 07:35 PM   #2  
Sorry, but I'm not sure which springs you are referring too.


GregH.........HVAC/R Tech

 
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04-04-04, 07:56 AM   #3  
WHEELERBUFFY:

Could sure use some feedback on your tester question.


GregH.........HVAC/R Tech

 
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04-06-04, 06:09 PM   #4  
SPRING PRESSURE

Originally posted by GregH
WHEELERBUFFY:

Could sure use some feedback on your tester question.
valve springs
thanks--mccoy

 
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04-06-04, 07:40 PM   #5  
Ah, Ok.

I'm not sure of the pressure range of those springs but you could rig up something like a fish scale.
Also maybe you could put the spring on some kind of platform scale and rig up a lever of some type to push down on the spring and then read the scale.

This is outta my area of expertise though so I'll copy this to our Small Engines forum where the folks that really know this stuff are.


GregH.........HVAC/R Tech

 
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04-06-04, 10:30 PM   #6  
What are you wanting to measure units of? A spring has no pressure unless it is compressed. If you were to compress it with a hinged fulcrum, with the spring on a scale, you would have to be able to calculate how much downward force is applied to the end of the fulcrum, how long the fulcrum is, the distance between the hinge and the center of the spring, and the reading of the scale to begin a mathematical process to determine the resistive force of the spring in whatever units you want to measure that in.

Man...that sounds like a bunch of mumbo-jumbo. Maybe I should just say, no, there's no simple way to do it, lol. (that I know of).

If you want to compare springs just to find out which is stronger, use a fish scale capable of reading quite a bit of weight...up to 80 or 100lbs would be ok. Hook it to a piece of wire that connects to a piece of metal that spans across the top of the spring, and hook a wire to a similar piece across the bottom of the spring. Feed both wires through the center of the spring. Connect one wire to a strong hook in the wall, and the other to the hook on the fish scale. Pull the scale until the spring compresses to whatever given length (say 1 1/2"). Read the amount of weight the scale says. Then do the same thing with the other spring. Whichever requires the highest reading on the scale to compress the spring to the same length is the strongest spring.


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04-07-04, 09:53 AM   #7  
Springs have what is known as a spring constant. The idea is that a spring will always compress a known distance when subjected to a known force. For the most part this relationship is linear in the normal working area of the spring. I've seen specs for the springs I put in my Chevy engine, but I've never seen a spec for a Briggs or Tecumseh engine. That doesn't mean you couldn't try to measure a known good spring and determine the number for yourself. See the diagram. The weight selected should compress the spring about the same distance that the spring gets depressed in normal service inside an engine. You could then compare what you see with a known good spring against springs that were of unknown quality. I've actually used such a device to measure the spring constant of springs in the physics lab in college and the method will indeed work. The accuracy you get depends on how accuractly you can measure the weight you use and how close your distance measurements can be made.

<img src = "http://ronj48.home.mchsi.com/spring1.jpg">


Last edited by jughead; 04-07-04 at 11:42 AM.
 
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04-07-04, 06:39 PM   #8  
Nice pic there Jughead, you draw yourself? How is the spring situation, were we any help to you?

 
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