After 25 yrs its out!

 

 

Hurst390 wrote: SKeown wrote:    255 x 650 will carry you past 7500 RPM. You wont benefit from anything beyond that.    SKeown your wrong

 

Edited by SKeown - Dec/22/2012 at 10:30am

 The only relevance to the discussion is sparing Tony unnecessary aggravation resulting from excessive valve spring pressures for his application and intended use. I would like to spare him the oreal he endured during the power tour.

 

 Overkill in such areas may not bight you in a tow to track then make a half dizen passes scenario. What he intends to accomplish is a different matter. Ering in the direction of undue stress would be appropriate in my estimation.

 

 Some builders setup their springs with excessive pressures to forstall the need for replacement. Valve springs start loosing tension pretty quick, particularly with agressive cam profiles. The 225 x 590 springs started showing signs of fatigue after two seasons. What I discovered was some springs were much weaker than others, it seemed the heavier intake valves had an effect. Being I had room to further work with those springs, I had the retainers step for the inner springs reduced so both inners and outers stacked at the same height, mixed and matched inner and outer springs to get matching pressures, then shimmed them to within .060 of binding. At that point I had raised both their seat and open pressures beyond the initial rates. I ran them that way for the following year without issue, they actually seemed to stabilize quiet a bit at that point. These were expensive PSI polished silicone "endurance" type springs, so I figures the expereiment was worthwile.

 

 SKeown