Re: Solid roller camshafts spring pressure ?
[Re: franko]
#2016771
02/21/16 07:56 PM
02/21/16 07:56 PM
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Joined: Sep 2007
Posts: 14,889 up yours
Supercuda
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Posts: 14,889
up yours
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Sure, but will the valves float? Probably.
Best help, with the limited info given, is to do what the cam manufacturer recommends.
A number of things go into determining valve spring pressure requirements, lift, rate of lift, rpm, ect. None of which we have.
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
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Re: Solid roller camshafts spring pressure ?
[Re: franko]
#2016857
02/21/16 09:33 PM
02/21/16 09:33 PM
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Joined: Sep 2007
Posts: 14,889 up yours
Supercuda
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Very generally speaking, yes, but there is a limit how low you can go.
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
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Re: Solid roller camshafts spring pressure ?
[Re: franko]
#2016925
02/21/16 10:47 PM
02/21/16 10:47 PM
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Joined: Aug 2003
Posts: 43,163 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,163
Bend,OR USA
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Why do you want to reduce the pressures you have now? I've always been told(for over 40 yrs) on solid roller race cams by other hard core racers and the cam racers reps(not the 1-800 cam help) it is way better to have more valve spring pressures to start with than the minimum as new springs will loose presuure after being ran, raced and warmed up and cooled down when racing them Years ago I bought a Rimac 1000 lb. spring pressure checker due to being told by several different cam racers reps to set up all the good race valve springs up so they had between .060 and .080 on each spring before coil bind, if that meant that I ended up with 20 to 50 lbs more pressure opened it was okay as they would loose bewteen 20 to 30 lbs after 60 to 80 runs, which they would. I would recheck them after 100 runs or so and reset them up, on some I could add a .015 or maybe even a .030 shim and get them back to .060 from coil bind and raise the pressures up to or above the pressures recommended originally and get another 60 to 100 runs out of them before having to replace them The main thing I've learned on racing valve spring pressures on solid roller cams is to look at the back side, closing side, of the lobes, if there are no roller tracks all the way around the lobe, especially on the closing side from the nose for a short space down to the ramp, to raise the pressure so the roller couldn't hop or launch off the nose or top of the lobe and come crashing back onto the lobe further down from the top of the lobes On solid roller race cams valve spring pressure having more than what recommended is way better than a tiny bit to little
Last edited by Cab_Burge; 02/21/16 10:51 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Solid roller camshafts spring pressure ?
[Re: dvw]
#2017179
02/22/16 04:22 AM
02/22/16 04:22 AM
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Joined: Jan 2003
Posts: 27,421 Balt. Md
383man
Too Many Posts
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Posts: 27,421
Balt. Md
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Weak springs will hammer the bearings in the tappets worse than high spring pressure. What are the cam specs? What is a "large drag race roller"? Specs? Doug This is right as any valve float or anything that can let the valves bounce or hammer on the roller lifter wheel is not good for the roller lifter. You want enough spring pressure to keep that roller wheel on the cam. Why not go with a street type of hydraulic roller as they run less spring press then what you have ? Ron
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Re: Solid roller camshafts spring pressure ?
[Re: Cab_Burge]
#2017493
02/22/16 04:57 PM
02/22/16 04:57 PM
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Joined: Aug 2005
Posts: 4,799 ILL
MLR426
master
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master
Joined: Aug 2005
Posts: 4,799
ILL
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Why do you want to reduce the pressures you have now? I've always been told(for over 40 yrs) on solid roller race cams by other hard core racers and the cam racers reps(not the 1-800 cam help) it is way better to have more valve spring pressures to start with than the minimum as new springs will loose presuure after being ran, raced and warmed up and cooled down when racing them Years ago I bought a Rimac 1000 lb. spring pressure checker due to being told by several different cam racers reps to set up all the good race valve springs up so they had between .060 and .080 on each spring before coil bind, if that meant that I ended up with 20 to 50 lbs more pressure opened it was okay as they would loose bewteen 20 to 30 lbs after 60 to 80 runs, which they would. I would recheck them after 100 runs or so and reset them up, on some I could add a .015 or maybe even a .030 shim and get them back to .060 from coil bind and raise the pressures up to or above the pressures recommended originally and get another 60 to 100 runs out of them before having to replace them The main thing I've learned on racing valve spring pressures on solid roller cams is to look at the back side, closing side, of the lobes, if there are no roller tracks all the way around the lobe, especially on the closing side from the nose for a short space down to the ramp, to raise the pressure so the roller couldn't hop or launch off the nose or top of the lobe and come crashing back onto the lobe further down from the top of the lobes On solid roller race cams valve spring pressure having more than what recommended is way better than a tiny bit to little I agree Cab and that's what I do, use all available open pressure of the spring .080 before coil bind. Controlling the valve and spring from bounce or float is key to getting the most out of your valve train and not damaging it or the cam. MLR426
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