New Cams....need valvesprings?
11-20-2013, 03:02 PM
#1
New Cams....need valvesprings?
I am in the midst of pulling my motor to freshen it up and cams are on my list.
I am pretty sure I will go with a set of DC21 or RS cams from Patrick motorsport. That being said, do I need to change the springs? I don't plan on changing the rod bolts to ARP or revving it past the stock redline, I just want a little more mid range upper end. I know stronger springs can cause premature cam wear, but if I am not revving it any higher are they really necessary? I have done several searches and haven't found a definitive answer.
Thanks!
JM
I am pretty sure I will go with a set of DC21 or RS cams from Patrick motorsport. That being said, do I need to change the springs? I don't plan on changing the rod bolts to ARP or revving it past the stock redline, I just want a little more mid range upper end. I know stronger springs can cause premature cam wear, but if I am not revving it any higher are they really necessary? I have done several searches and haven't found a definitive answer.
Thanks!
JM
11-21-2013, 12:39 AM
#2
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If it was me, newer high lift cam warrants matching new heavy duty springs and titanium retainers. Your stock springs will do overtime with the new cam and eventually fail. Rod bolts are the weak link in what is a relatively heavy but robust rod. ARP rod bolts are cheap insurance if you plan on consistent spirited driving.
Dan
PS Forgot to mention depending on how much lift on the new cam you might get spring bind with the new lift and drop a valve.Check with Patrick Motorsports or reputable Porsche tech.
Dan
PS Forgot to mention depending on how much lift on the new cam you might get spring bind with the new lift and drop a valve.Check with Patrick Motorsports or reputable Porsche tech.
Last edited by pantera43; 11-21-2013 at 01:24 AM.
11-21-2013, 01:36 AM
#3
RL Technical Advisor
I am in the midst of pulling my motor to freshen it up and cams are on my list.
I am pretty sure I will go with a set of DC21 or RS cams from Patrick motorsport. That being said, do I need to change the springs? I don't plan on changing the rod bolts to ARP or revving it past the stock redline, I just want a little more mid range upper end. I know stronger springs can cause premature cam wear, but if I am not revving it any higher are they really necessary? I have done several searches and haven't found a definitive answer.
Thanks!
JM
I am pretty sure I will go with a set of DC21 or RS cams from Patrick motorsport. That being said, do I need to change the springs? I don't plan on changing the rod bolts to ARP or revving it past the stock redline, I just want a little more mid range upper end. I know stronger springs can cause premature cam wear, but if I am not revving it any higher are they really necessary? I have done several searches and haven't found a definitive answer.
Thanks!
JM
If its strictly a street car and you will not be doing any DE events, different springs & retainers may be a waste of money for you.
OTOH, if you plan on doing track days, I'd highly recommend installing better springs & retainers as well as having your rods reconditioned with ARP bolts. Racing valve springs are NOT all alike and differ by seat pressures. Consult your engine builder and choose wisely to avoid putting undue stress on cams, rockers, chains and sprockets.
Naturally, this is JMHO, however I hope this helps a little bit.
11-21-2013, 09:07 AM
#4
Nordschleife Master
It isn't so much stiffer springs that would be needed, but rather the install height of the spring needs to be determined to obtain the proper spring pressure on the seat and over the nose. Your camshaft manufacturer should provide those pressures for you once you give him the mass of the valvetrain and your max RPM, accounting for a safety margin. From there, you can determine if the stock springs will work for you.