what will break valve springs?
06-28-2008, 03:18 PM
#13
Senior Member
RACING JUNKIE
Join Date: Jul 2007
Location: Florida
Posts: 635
Running the springs you have that tight may not be feasible, in addition to the fact you broke one they already may be hurt. I would look at the PAC or PSI, they coil bind a little higher. You can get away with as much as .120 to coil bind, but the idea is to use a valve lift that matches the spring when you start running more than about 7500 RPM. That way the seat height and open height are optimum for spring, putting coil bind height where it need to be without excessive seat pressure. Mine ended up with .075 intake and .095 exhaust distance to coil bind.
06-28-2008, 08:26 PM
#14
Senior Member
MASTER BUILDER
Thread Starter
Join Date: Oct 2003
Posts: 144
Ok,
I have now been ingulfed by this coil bind, / spring height setup.
when the springs are installed at the height that is advertised say 2.0 inches and coil bind is at say 1.15 and my cam total lift is say .700
I should set up with .070 shim to get somewhere in the .080 range before coil bind ??
Now on the other hand, if my cam total lift was , .770 then would I be in the ball park? And if so how would that "Tighten the springs as you say?
kinda curious?
It is very interesting what happens at high speeds in the v. train.
Thanks
Alan
I have now been ingulfed by this coil bind, / spring height setup.
when the springs are installed at the height that is advertised say 2.0 inches and coil bind is at say 1.15 and my cam total lift is say .700
I should set up with .070 shim to get somewhere in the .080 range before coil bind ??
Now on the other hand, if my cam total lift was , .770 then would I be in the ball park? And if so how would that "Tighten the springs as you say?
kinda curious?
It is very interesting what happens at high speeds in the v. train.
Thanks
Alan
06-29-2008, 08:19 AM
#15
Senior Member
MASTER BUILDER
Join Date: Nov 2004
Location: Port Sulphur, La.
Posts: 139
coil bind
I just went thru this with the same springs. I used a shim, standard height retainers than the normal +.100 that are usually used, and a .060 spring cup on the ex instead of the .030 that came standard. This got me in the ball park with my .800 + cam. As with most cams Ive seen, You will need more shim on the EX as it has even less lift. As I was advised, stacking a lot of shims is not good. You can also get -.050 keepers. I had 2 pages of responses when I did It, I will try to find it, Good Luck. :wink: Found it, search Speedtalk, Broke Valve Springs, by travlinman572, check it out.
06-29-2008, 08:52 AM
#16
Senior Member
RACING JUNKIE
Join Date: Jul 2007
Location: Florida
Posts: 635
When a spring is run closer to coil bind, it dampens the bouncing/surging when it is around peak lift because there is little room to move. If too much distance is available at peak, it can't dampen the surge. On an engine under 7500 RPM this is not as much an issue. It is even possible to have the spring set up correctly, but the harmonics of the spring is wrong for the RPM you are running. This is why I suggested a different brand. Edvanced engines Ed Wilson here is a dealer for PAC and can probably get you a fair price on them. Spend the money for an on the head spring tester to keep tabs on your springs, LSM or Pro Comp will do the job.
