Originally Posted by Dwight Southerland (Post 485801)

Not exactly a complete analysis. While "not enough" valve spring pressure can cause failures as you describe because of lack of control, I would also have to say that the allowed increased spring pressure has promoted running the engines at a much higher rpm range and demanded much more radical camshaft dynamics which have contributed to more failures than not enough valve spring pressure. The stresses on valve train components increase geometrically with the rpm, which contributes to parts failure more than the "not enough" spring pressure as you point out. Also, without the increased spring pressure, having to resort to parts like the ceramic lifters or tool steel lifters would not have been necessary. The camshaft manufacturers are smart guys and will produce profiles that work with whatever pressures are available, so you think that they are not pushing the limits of design to take advantage of the increased pressures and increasing engine speeds and ramp events accordingly? They also pushed limits in the same way when we ran OEM valve spring pressure, but the spring pressure limitation kept the engine speeds lower and camshaft dynamics softer so parts were not stressed nearly as much. The snowball effect of the consequences of that one rule change has escalated the cost of stock eliminator more than any other, and it simply was not necessary.

Originally Posted by Dwight Southerland (Post 485801)

Not exactly a complete analysis. While "not enough" valve spring pressure can cause failures as you describe because of lack of control, I would also have to say that the allowed increased spring pressure has promoted running the engines at a much higher rpm range and demanded much more radical camshaft dynamics which have contributed to more failures than not enough valve spring pressure. The stresses on valve train components increase geometrically with the rpm, which contributes to parts failure more than the "not enough" spring pressure as you point out. Also, without the increased spring pressure, having to resort to parts like the ceramic lifters or tool steel lifters would not have been necessary. The camshaft manufacturers are smart guys and will produce profiles that work with whatever pressures are available, so you think that they are not pushing the limits of design to take advantage of the increased pressures and increasing engine speeds and ramp events accordingly? They also pushed limits in the same way when we ran OEM valve spring pressure, but the spring pressure limitation kept the engine speeds lower and camshaft dynamics softer so parts were not stressed nearly as much. The snowball effect of the consequences of that one rule change has escalated the cost of stock eliminator more than any other, and it simply was not necessary.

Originally Posted by Mike Taylor 3601 (Post 485858)

The stockers I build have plenty of spring pressure,they make more runs and require less maintenance than my pure stocker with stock spring pressure does,there valves,guides,spings,valve jobs will last twice as many runs as my pure stocker does..
Mike Taylor 3601