Re: Valve spring pressures and testing
[Re: mopar dave]
#2700149
09/23/19 02:28 PM
09/23/19 02:28 PM
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Joined: Jan 2003
Posts: 4,733 Moved to N.E. Tennessee
GomangoCuda
master
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master
Joined: Jan 2003
Posts: 4,733
Moved to N.E. Tennessee
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Which pressure is most importance, the seat or the open? Which ever one is off by enough to damage the cam or valve train parts. Sorry but if either open or closed pressures are too high or too low then Carnage is the result.
Last edited by GomangoCuda; 09/23/19 02:30 PM.
In theory, there is no difference between theory and practice. In practice, there is.
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Re: Valve spring pressures and testing
[Re: GomangoCuda]
#2700152
09/23/19 02:37 PM
09/23/19 02:37 PM
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Joined: Jan 2003
Posts: 4,733 Moved to N.E. Tennessee
GomangoCuda
master
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master
Joined: Jan 2003
Posts: 4,733
Moved to N.E. Tennessee
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Also with that much lift you have to check for coil bind and retainer to valve guide/seal clearance.
In theory, there is no difference between theory and practice. In practice, there is.
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Re: Valve spring pressures and testing
[Re: mopar dave]
#2700263
09/23/19 08:31 PM
09/23/19 08:31 PM
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Joined: Dec 2007
Posts: 12,588 Great Neck,LI,new york
hemi-itis
I Live Here
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I Live Here
Joined: Dec 2007
Posts: 12,588
Great Neck,LI,new york
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Todd is a well respected member,and I mean him no disrespect,,,,,,,,,but in your location there are several machine shops that could give you a good squeeze,,,,,,and your springs too!
HEMI-ITIS has no cure. My condition is fully BLOWN!!
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Re: Valve spring pressures and testing
[Re: mopar dave]
#2700264
09/23/19 08:40 PM
09/23/19 08:40 PM
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Joined: Oct 2007
Posts: 4,209 New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,209
New York
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Spintron has revealed something not believed possible decades ago: "these 600 lb. spring are permitting the parts to separate at several different RPM levels". Right - not just float at peak RPM. Assuming safe break-in: too little spring is more dangerous than too much. If you gap the parts, they will break.
Boffin Emeritus
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Re: Valve spring pressures and testing
[Re: mopar dave]
#2700729
09/25/19 10:39 AM
09/25/19 10:39 AM
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Joined: Dec 2007
Posts: 12,588 Great Neck,LI,new york
hemi-itis
I Live Here
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I Live Here
Joined: Dec 2007
Posts: 12,588
Great Neck,LI,new york
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Dwayne and Todd and friends. Dwayne spec'd the cam, so I feel confident Todd will get me on the right track with this spring ordeal. Incompetence in many shops and businesses around here is over the top. Doesn't matter what kind of business it is, some people just don't give a sh!t no more and its getting worse. You have who you need and one phone call gets them delivered to your door!
HEMI-ITIS has no cure. My condition is fully BLOWN!!
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Re: Valve spring pressures and testing
[Re: mopar dave]
#2700733
09/25/19 10:53 AM
09/25/19 10:53 AM
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Joined: Jan 2003
Posts: 14,506 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 14,506
So. Burlington, Vt.
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Yes, I have a friend that feels I should run more spring pressure. Not that it matters, but he is a Hemi guy, Jim Keys wrench who maintains Jims 68 Hemi cuda super stock car. He has his own factory stock car he runs as well. He runs much more spring pressure on his SFT cams and they live. I just do not want to flatten a cam in this engine. Does he have a good quality spring tester? It’s really quite simple. There is either a valvetrain control problem...... or there isn’t. If there is, you need more spring load, or a different spring altogether....... or lower the engines operating range so you’re not running the motor in the range where the loss of control is occurring. If there isn’t a control problem, you have other issues(or the combo just doesn’t work that well). Obviously, the best way to determine exactly what’s going on is to dyno the motor. That answers (at least) two questions. It will show whether or not there is a valvetrain control issue that’s keeping the motor from realizing it’s potential...... and whether or not it makes enough power to achieve the desired goal as is....... or if more power is needed to get there. I’ve tested many motors........ after the owners had spent thousands and thousands of dollars trying to get their car to run a number that the motor didn’t make enough power to achieve. In most of those cases........ the car was going as quick as it “should”.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Valve spring pressures and testing
[Re: mopar dave]
#2700800
09/25/19 02:46 PM
09/25/19 02:46 PM
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Joined: Oct 2007
Posts: 4,209 New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,209
New York
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Sometimes a dyno run will show a narrow band of small spikes at an RPM where nothing should be happening. That's what VT harmonics or weak springs will do. This also happens with pushrod flex, IDK how to distinguish between them. The usual rule is "If you don't have the biggest pushrods that fit, get them".
Boffin Emeritus
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Re: Valve spring pressures and testing
[Re: mopar dave]
#2700931
09/25/19 08:42 PM
09/25/19 08:42 PM
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Joined: Aug 2003
Posts: 43,228 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,228
Bend,OR USA
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Dwayne, my thinking is, you know the cam and Todd knows the springs. So I figure I have the best two guys on this possible problem. As soon as the weather turns here, I will box up 4 springs and send them to Todd for inspection. DON,T do just four, send them all You know Murphy loves messing with us hot rodders and drag racer, don't you One bad spark plug wire can drive you CRAZY
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Valve spring pressures and testing
[Re: Cab_Burge]
#2700933
09/25/19 08:48 PM
09/25/19 08:48 PM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
Taking time off to work on my car
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Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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Send 'em all. Dwayne checked a set of mine after a problematic dyno session years ago and found a number of the intake springs had lost a lot of pressure during the tests.
Do you know the advertised specs for your springs?
Last edited by BradH; 09/25/19 08:50 PM.
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Re: Valve spring pressures and testing
[Re: Cab_Burge]
#2701156
09/26/19 02:59 PM
09/26/19 02:59 PM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
Taking time off to work on my car
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Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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I've seen guys remove all 16 springs on the motor by using clothe pins or additional valve seals on them Buy a set of 16 of the soft checking springs and simply swap the real springs out for the checking springs while they're off getting tested. Be aware you need to shop around a bit cuz some of the parts vendors ask as much for 2 springs as others might for a set of 8. Or, if Dwayne suggested only needing to send four, pick 2 intakes & 2 exhausts (which I suspect was your plan) to be able to see if there's a pattern in load degradation between the two sides. So, what pressures & heights are (were?) the springs set up for?
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