Saturday, 24 November 2018

WHAT YOU NEED TO KNOW ABOUT THE VALVES OF A CAR - Everything about valves


There is much more than valve springs than sitting and open pressures. Here's what you need to know.
For many years, the camshaft technology was limited not by the lack of knowledge about cam profilers, but by valve technology that was not suitable for stabilizing aggressive wing structures. However, in the last 10 years, spring material and structural improvements have been improved, which - in combination with ever lighter valves - allow the full potential of modern cam profiles and high-performance cylinder heads. Today we have more spring options than ever before, but it also means that it is
easier to go astray or quickly get confused about all the complexities of installing and configuring valve springs.

New technique, new thinking

In relation to high-performance work, the primary function of the valve valve is to prevent the valve float, defined by Godbold as the "limiting speed of the valve in which the spring does not control the movement". The more radical the camera, the more springs you need. Traditionally, spring-loaded engineers have made stiffer springs using better materials, increasing the number of coils and / or increasing the size of the
coils. As the cameras became more aggressive, the springs became larger, heavier and more elements were added: Duals replaced the singles, the trios replaced the duals. In the end, it became unproductive, because much of the pressure on the larger spring was wasted trying to control its own weight.

The choice of spring
One of the biggest questions about valve springs is whether you can use general springs and valve parts, or whether the cam, springs and other critical engine parts must be made as an integrated packaging from the same manufacturer. There is no stalemate response. Many non-genuine heads are mounted with generic springs for a specific type of cam (flat pusher, hydraulic cylinder [HR] or fixed shaft) and usually works well with an average hot rod. On the other hand, you can always play, paying attention to every detail. Of course, the higher the intended rpm scope and / or the larger the camera, the more critical these things become. You will probably have to take a closer look if you will routinely perform 7,000 rpm. Or more and / or run cameras with a duration of 240 degrees or longer (at 0.050-inch pusher lever).

It is also controversial to choose a spring for hydraulic roller cams. Originally, the HR hoist was based on OEM technology. Although they were more intense than ordinary grinders, special cam grinders still determined relatively soft springs to maintain 100,000 miles in length thanks to OE-based elevators. This often caused the premature mouth of the valve, which prevented the new grinders from using their full potential. Running disc springs solves the problem on dyno, but can reduce the final longevity. Currently, new lightweight and short HR lifts are available from secondary sources as well as advanced OEM applications that significantly reduce the need for compromise.

Beehive Vs. Conventional
Even on a relatively smooth 406ci Chevy small block with a hydraulic roller cam, the spring containing the latest technology can make a big difference. Westech Performance has tested the traditional Comp Cams double spring with a flap (PN 954) on one of the new individual spring springs Comp (PN 26918). The 954 developed 210 pounds per seat and 523 pounds open, compared to specifications 26918 at 130/318 pounds. Both springs were installed with titanium fixing elements and locks, but the connection of the beehive was still 52 g lighter. If the steel engine valves were replaced by titanium valves instead, the weight savings would be as low as 40 grams.

The total peak performance was virtually the same: 418.4 pound-foot for 954 compared to 418.9 pound-legs for 26918, both at 4800 rpm; and 418.2 hp compared with 419.3 hp for the models 954 and 26918 respectively at 5,800 rpm. The average performance in the test range of 2500 to 7000 rev / min differed only by two numbers. But above 6,500 rpm the difference was huge: the new 26918 technology effectively increased the engine speed range, proving it to be between 15 and 36 hp and between 12 and 28 pounds at the top. Stiffer 954 produced more low-current torque, because its higher loads actually bent other elements, effectively reducing the valve's operating time.

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