Testing Valve Springs
04-14-2002, 10:59 AM
#1
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Testing Valve Springs
Just tested my seat pressures yesterday and was looking for some input as to if its time to change valve springs. Can't talk to my engine buider until tomm. 632 merlin; Comp solid roller 280 / 288 @.050 on 115 centerline; .785 / .760 lift. Comp 948-16 springs with about 40 hrs on them. thanks for the input.
Cylinder;Intake;exhaust
1 285 290
2 280 295
3 285 290
4 280 295
5 285 295
6 275 270
7 280 295
8 270 280
Cylinder;Intake;exhaust
1 285 290
2 280 295
3 285 290
4 280 295
5 285 295
6 275 270
7 280 295
8 270 280
04-14-2002, 07:23 PM
#2
I hate the winter!!
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I would consult with either the cam card or Comp. Cams for the recommended spring pressure for that cam. That takes all the guess work out of it.
04-15-2002, 09:33 AM
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I am wondering what is the best way to test valve springs. JDNCA1 said it is hard to tell exactly when the valve is off of the seat and with aggressive roller cam springs slight variances in valve opening can cause considerable differences in measured force. Would it be better to use a dial indicator and measure each spring at say .010" lift off the seat? It seems to me this will give a more precise comparison than trying go by feel. Opinions from some engine builders or other solid roller users would be appreciated.
04-15-2002, 11:15 AM
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The ONLY correct way to do it is, to have a valve spring pressure tester.
It sits on your work bench, you put the valve spring in between the two surfaces and pull a handle (like a slot machine). It has a micrometer and pressure guage on it to tell you the spring pressure at that highth.
Dave
It sits on your work bench, you put the valve spring in between the two surfaces and pull a handle (like a slot machine). It has a micrometer and pressure guage on it to tell you the spring pressure at that highth.
Dave
04-15-2002, 01:22 PM
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Just one of the expenses of a high lift roller cam. Are you going to use the same spring or try a different mfg.? Erson p/n E915048 claims it will last 1.9 million cycles. They claim the comp 948 will go .2 million, the Manley 221048 will go .15 million, and the Manley 221148 will go .7 million. I don't know the test parameters, but these numbers are printed in their spring catalog. Sounds worth checking out.
