Valve spring pressures?
01-21-2010, 07:34 PM
#1
Staging Lane
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Valve spring pressures? I have AFR 205's, and when i was at the engine shop that put together my bottom end, they recommended that they test the spring pressures. The #8017 springs advertised at #135@1.800 and #340@1.230. We measured #150@1.785 and #390@1.185! This seemed odd to me!? Now i was told by the shop that these are too stiff and would cause lifters to blead down and cause ticking in the valve train and possibly more issues.
Then i called AFR was told that those pressures are fine with hyd. lifters. I just want the optimal springs for my setup. So basically regardless of weather the pressures were measured correctly or not, are those numbers acceptable for hyd. lifters? Do you have recommendations for different springs that will be better for my setup? Thanks in advance for your help!
Then i called AFR was told that those pressures are fine with hyd. lifters. I just want the optimal springs for my setup. So basically regardless of weather the pressures were measured correctly or not, are those numbers acceptable for hyd. lifters? Do you have recommendations for different springs that will be better for my setup? Thanks in advance for your help!
01-22-2010, 04:42 AM
#3
The 8017 springs have a stiffness of 360 lb/in per the AFR web site. The 8019 springs have a stiffness of 428 lb/in. Since springs will get weaker with use lets look at your values.
(390-150)/(1.785-1.185) = 400 lb/in
Looks to me that you don't have 8017 springs but rather 8019 springs. These are excellent springs and a lot of guys run these springs (including me) without issues on a hydraulic lifter. I am now running Morels though, which will handle much higher valve spring forces.
(390-150)/(1.785-1.185) = 400 lb/in
Looks to me that you don't have 8017 springs but rather 8019 springs. These are excellent springs and a lot of guys run these springs (including me) without issues on a hydraulic lifter. I am now running Morels though, which will handle much higher valve spring forces.
01-22-2010, 03:25 PM
#4
Staging Lane
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I can guarentee that the springs i have are thoe #8017's because we measured the OD which measured 1.290. Do you think that new ls7 lifters could handle these pressures? Im just confused because im getting mixed opinions about what to do so any more input would be greatly appreciated!
01-22-2010, 05:42 PM
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The 8017 and 8019 spring look identical from the outside and will measure the same size physically. It sounds like you might have the 8019's but they could still be 8017s since they are shimmed to 1.785. The pressure increses as you shim the spring. Either way, you will be fine with hydraulic lifters. I run MUCH more
spring pressure than that in some applications with no issues whatsoever. I never order the 8017's anymore because with most cams used these days, the 8019's are a much better choice.
Shane
spring pressure than that in some applications with no issues whatsoever. I never order the 8017's anymore because with most cams used these days, the 8019's are a much better choice.Shane
