JacksonAuto
15+ Year Contributor
- 753
- 131
- Nov 21, 2005
-
Hanover,
Maryland
9!'clipseDOHC;152347683 If I wanted to go "all out" on the springs I would use the Kiggly Beehives. [/QUOTE said:I guess our opinions of "all out" differ a bit. I would never recommend a single spring for any all out application.
When we assemble a package or recommend a component, it has been chosen because it compliments the others and will work as a combination to ensure that nothing is left on the table in terms of reliability or power. The stock Evo springs have their place but it's not with more aggressive aftermarket cams. As the duration of a cam increases, so does the steepness of the ramps. In order for the cam follower to stay in constant contact with the lobe it needs a spring with higher pressures for it to perform properly. Otherwise the follower will lose contact with the cam. As the follower passes the point of peak lift and the valve should now begin to close, the inertia actually carries the valve further open. This is known as valve loft. Then, once the spring catches up and actually does close, the follower slams into the back side of the lobe. So now you've got a valve that has opened further than it's supposed to be which puts it dangerously close to hitting the piston and you have a follower beating up the camshafts. Because larger cams also tend to close the valve much more aggressively, this will give the valve a higher propensity to bounce. When it slams shut against the seat, a weak spring will often allow it to bounce right back up off the seat. In addition to bleeding off compression and costing you power this action absolutely destroys every component of your valve train. A weak spring will also allow the valves to float. At higher RPM's, the valve spring simply cannot open and close fast enough so you end up with a situation very similar to valve loft whereby the follower cannont maintain contact with the cam. Also, the stock springs were not designed to tolerate higher lift. Also, as a spring is compressed it generates heat. The closer a spring gets to approaching coil bind, the more heat it generates. As it begins to overheat it's pressures change and if this happens just once the the tension is gone.
Valve loft, float and bounce are where bent/dropped valves come from. You also end up with beat up seats that don't seal and give you bad leakdown and compression numbers. Cams will wear out quicker. These problems also cause noises that the lifters usually get blamed for. Ever hear someone say they upgraded to 3g lifters but the noise didn't go away? Many times it's because they've got the wrong combination of parts rattling away inside the head and it's got nothing to do with lifters. Will it run with stock springs? Yes, for a period of time. However, they cannot maintain proper geometry and dyanamins which means you will sacrifice power and you will experience premature failures.
This is what happens when you put a hodge-podge of parts together that were never designed or intended to be used with one another. Often recommended by someone on a forum that has no business giving out advice.
I can't speak for you, but we're drawing from 80 years of combined experience here at the shop building and racing high performance engines. I'm not sure why you've got a problem with us but please, if you feel the need to argue the point further, please take it to PM's. I'm here to help you guys out not argue about a $25 price difference in a set of springs or have you tell my why my recommendation of them was wrong.
We started with DSM's in '95 before anyone here knew what an Evo was and had the first 8 second 4G63 in 2001. What difference does it make anyway? As far as the valvetrain is concerned they are nearly identical.
