Over the last few months, there have been some discussions about valvesprings, much without data or hard information. So anyway, I thought I'd share and article and an offer to get the ball rolling here.

First some background. I'm a physicist, so I'll start from springs and masses. The point of a valve spring is to keep the valve following the cam profile throughout the RPM range of interest. Pretty simple, yes? So then why are springs rated at things like 80 lbs seat pressure closed, and 200+ lbs seat pressure open to just keep a little valve that weights at most a couple ounces where it's supposed to be? Don't those numbers sound excessive?

So, let's think about the valve train. There is a camshaft with it's lobes. There is some form of rocker that rides the lobes, pivots somewhere, and presses on the end of the valve. This is for overhead cams (standard V8s have lifters and pushrods, but the idea is the same). What pushes back on all this stuff to keep it from rattling is the valvespring. It sits on the top of the head, and is kept in place by the retainer and lock. So this spring has to be able to push all this hardware back against the cam lobe.

The real killer hear is that as things go fast, it's not the basic static weight of the parts that comes into play. The spring has to overcome the inertia of the valve, the retainer, the lock, the rocker, as well as the spring (or springs) themselves. At 7000+ RPM, this takes a lot more force than is needed to just hold the parts against the force of gravity. Thousands of times the force. It can get pretty staggaring.

So, what does all this matter? For our Tritec engines, the choices for valvesprings have, until recently, been pretty limited. Every head I've seen has used some form of convetional spring. No one was offering beehive geometry. Some used Ti retainers, some used the stock steel ones. Some used single springs, some double. Some of the springs needed pocket work cause they were too long, and some needed spacers cause they were too short. None of this is bad per se, but it's all the consiquence of using parts pretty much designed for other applications and used because they were "close enough".

So, what's different? Well, nothing really. The PAC Racing Springs in the NS Valvespring and Retainer kit aren't custom for the MINI. They are, in fact, "close enough" springs found in the PAC spring catalog. What is different with the set is that the retainers are custom to the MINI so that a spring that is a touch too long can be used without machining a deeper pocket. What is new is that this is the first spring set for the Tritec that uses ovate wire (oval spring wire) and beehive geometry. The result of this is a lower mass spring and retainer set that has reduced harmonics compared to conventional springs.

Now, in some of the PMs that I've gotten from people, some who were not really happy when about the debate about springs, there was one quote that stuck in my mind: "You know that no one can feel the difference between one valve spring and another." And to be honest, I think that if the springs are properly selected, that may even be true. But we have a group of people in MINIs who are pushing ever higher RPM, and using aftermarket cams with more lift and aggressive profiles (this is called "ramp" to the cam guys). The faster the ramp, the faster the acceleration of the parts. Agressive ramp is the key to the NS cams benefits with lower overall lift (but that's another story). Anyway, we're demanding more and more out of the valvespring and retainer. And some are doing this with stock, or stock equivalent springs (for example the Cosworth single spring setup was a stock-equivalent spring. Same strength as the stock, just more consitent in specifications.)

Think this is all just marketing BS? Well, this is why I love Hot Rod Magazine. Sure it caters to the V8 Big Block crowd and American chassis and the like, but engines are engines, and they do some really great tech articles. The November issue was no exception and they have this article All About Valvesprings. I scanned it for your reading pleasure. It's seven pages (a lot for a mag article) and the high points of it are:

• In the past, valve train performance was limited by spring technology.
• Times have changed, and new geometries and materials have come into play.
• One V8 engine had significant high RPM HP increases when going to a SOFTER beehive from a dual spring set up!

So read away, and learn from the experts......

I've also got an offer to those that are interested in our spring and retainer set. The set retails for $385 on our site here. I want to get some of these kits into the hands (and onto the engines) of those that think they can benefit from them. So for the first 5 kits that are ordered in this offer, I'll let them go for $335 a set. To get this price, you have to do PayPal to sales@fes-auto.com. If you want to do a telephone credit card transaction, e-mail me at mattr@fes-auto.com.

If you have a stock motor, no tune, no cam, no nothing, these aren't for you. If you have a raised red-line and/or aftermarket cam, these may be just the ticket for really getting all the HP your engine has to offer as you bang the rev limiter!

Matt

ps, I'm pretty sure that in the coming weeks and months, you will see others offer Beehives for the Tritec. Why not? SuperTech, Ferrea, Comp Cams and others are using them for more and more applications! We use PAC Racing springs and are proud of it! Read all about PAC Racing at thier web site.