Originally Posted by ChevroletSS
AWWWWW, ok I didnt know all that, but I was talking about chevy small block. I didnt know it was that complex. Sorry guys. So if I am using a .420INT and a .442EXH Lift cam with 1.6:1 rockers its actual lift is what????? I cam up with .672INT and .707EXH. That dont seem right. Also what is dual and single pattern
Yeah it gets complicate fast, don't be sorry we all started out from less than we know now, how did that song line go,,,"I wish I didn't know now, what I didn't know then."
The math for rocker ratios is ratio your going to divided by the ratio your coming from in this case 1.6/1.5 equals 1.0667. That answer times the known valve lift for a 1.5 ratio rocker will yield the lift at the valve for the 1.6 rocker. So .420 times 1.0667 is .448 on the intake and the exhaust is .442 times 1.0667 which nets .478. Also the lift event happens faster with the increasing ratio as does the loading on all the components, no free lunches allowed.
Springs are fun in a not very funny way, get this wrong and you ruin a lot of expensive parts.
- Typically a single spring is just that a simple winding of a piece of really good wire.
- A single spring with damper is the addition of a flat cross section wire wound into a spring that rides against the inner coils of a single spring to absorb (dampen) the natural harmonics of the single wire that would cause it to continue bouncing once excited (just like the shocks on you car's suspension in purpose).
- A single spring may also come with variable distances between windings which tends to dampen harmonics without a seperate damper, they may be made from wire that is not round you will see the term "ovate" and in more modern designs we see a variable diameter of the winding in what's called the beehive. Beehives have a lot of advantages in being more self damping and will tolerate more RPMs before loosing control with less spring rate and pressure. A lot of this is due to using a smaller thus lighter retainer.
- Dual wound is actually two springs a smaller nested inside a larger. They are wound in opposite directions to gain damping of harmonic responses in either but the main attraction is increasing spring rate and pressure without increasing diameter, lenght or wire size.
- Tripple wound is more of the same as dual with one more nested spring.
I highly recommend that you use the camshaft manufacturer's recommended springs and retainers if not lifters and valves as well if these are specified. They have the equipment like a Spintron that lets them do the testing to determine whether a selected spring actually performs the task of keeping the valve train tracking the cam. Loss of control quickly leads to broken parts in some cases even the loss of the engine. While a major player in keeping control of the valve train can be found in spring rate and pressure, the harmonic respose of the spring, also, needs to be studied and included into the spring design This is more complex to calculate and needs to be studied for actual events compared to calculated to be proofed by test that the spring doesn't get out of control harmonically somewhere in the RPM range.