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Broken Spring Performance

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Old Apr 11, 2003 | 08:52 PM
  #1  
87Formula4bbl's Avatar
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From: Toledo, OH
Car: '87 Formula
Engine: 350
Transmission: Auto
Broken Spring Performance

Quick question:

What kind of performance loss would you see from a broken or weak valve spring? Would it be drastic?
Also, could this possibly cause a loud knocking sound at higher RPM's, but not at idle??

Any input appreciated. Thanks!
-Ben
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Old Apr 12, 2003 | 06:30 AM
  #2  
ede's Avatar
ede
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From: Jackson County
you'd have a dead hole, you'd know it
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Old Apr 12, 2003 | 09:32 AM
  #3  
RB83L69's Avatar
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From: Loveland, OH, US
Car: 4
Engine: 6
Transmission: 5
Yup, it would be drastic. It would manifest itself in other ways besides knocking noises.

If you have what sounds like a RPM-dependent knock that occurs at valve train speed as opposed to crank speed which is double the valve train speed, then it's probably a rolled / rolling cam lobe.
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Old Apr 12, 2003 | 10:22 AM
  #4  
87Formula4bbl's Avatar
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From: Toledo, OH
Car: '87 Formula
Engine: 350
Transmission: Auto
I'll check today to see if it is RPM dependent or if its the same frequency as the valvetrain. Hopefully this will give me a little better idea of the problem.
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Old Apr 12, 2003 | 11:52 AM
  #5  
V8Astro Captain's Avatar
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From: 600 yds out
Car: Bee-Bowdy
Engine: blowd tree-fity
Transmission: sebin hunnerd
Axle/Gears: fo-tins
Also, if you hook a vacuum gauge up to the engine a broken valve spring will make the needle bounce up and down rapidly.

...been reading my ASE A1 study guides too much!
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