Quick! What the fastest moving component in your engine? If you’ve taken a hint from the title of this article, you probably guessed correctly – it’s your valve springs, those tight little bundles of joy that open and close your engine’s valves.
Beehive springs, such as those offered by COMP Cams, offer a huge number of benefits over stock-style cylindrical springs; reduced valve spring mass, faster valve acceleration, increased valve train rigidity, reduced valve train component stress and a whole laundry list of other positives.
Best of all, the word has gotten out and folks all over the country are using them for a wide variety of applications from street performance to extreme racing endeavors. That’s a really good thing.
Along with their success has come some confusion over exactly which beehive is right to purchase. Currently there are over a dozen beehive spring styles out there, each offering some unique take, be it in the seat pocket diameter, ovate wiring diameter, pitch or internal spring “frequency.” Regardless increased selection has bred some minor confusion, albeit easily cured.
Beehive springs are conical shaped springs that employ this powerful shape in the creation of a spring that can deliver both excellent performance and lowered seat pressures. With lower seat pressure, valve train components (especially the pushrods, rockers and lifters) are less stressed to perform the same work.
According to COMP, effective beehive springs can support an additional 700rpm over stock cylindrical springs. How? It just stands to reason that the smaller coils at the top of the spring don’t require as much force to get the valve moving quickly, much quicker than conventional style springs. The higher rpm potential equates to better durability and performance.
There are some very knowledgeable engine builders who don’t understand how a single coil spring can be better than a dual conventional spring.
“Its like watching a race car running 60-foot elapsed times on the drag strip,” stated Bill Godbold, Chief Engineer for COMP Cams. “For example, take two identical cars with equivalent 500 hp engines.
“One has stock suspension and the other a sophisticated racing suspension. The car with the race suspension will get going more quickly and achieves better 60-foot time. The same principle works with beehive spring mechanics.”
If there is one challenge to the beehive revolution, it’s the perception of the masses. While most engine builders and performance enthusiasts know that the beehive works to improve their engines, many don’t realize the true benefits. Some established enthusiasts are confused and concerned that the smaller valve retainer and single spring used in the beehive system are capable of handling the same high performance loads carried by the conventional spring with two coils.
“There are some very knowledgeable engine builders who don’t understand how a single coil spring can be better than a dual conventional spring,” stated Thomas Griffin Head valve spring engineer for COMP Cams.
“The fact is the beehive springs, by virtue of the ovate spring shape and a variety of internal upgrades is compatible with virtually any application where a dual spring is used. That includes some engines with mechanical roller camshafts. The key is to review the required camshaft load and assess the aggressiveness of the camshaft.”
The key profile consideration of a camshaft can be denoted in the camshaft profile section. By reviewing the duration specs for your potential camshaft at 0.050-inch lift and again at 0.200-inch lift, the shape of the lobe can be projected. These are the key figures engineers use to determine beehive spring compatibility. Currently beehive springs for camshafts measuring up to 0.750-inch lift are available.
Questions to ask when picking a beehive valve spring:
1) Do they fit my current configuration valve seat diameter?
2) Do they fit the proper installed height for my cylinder head?
3) Do they have the proper seat pressure for the camshaft I have selected?
4) Do they encounter coil bind at any point in the spring’s compression?
5) Do they match the profile of my camshaft?
6) If I am running a roller mechanical camshaft, are they appropriate for the application?
If something sounds good, it’s worth investigating, except where valve springs are concerned. Sound is the key. While its great for musical instruments, valve train sound, or more correctly, resonance, is destructive. As with sound waves, resonance “frequencies” cause parts to pull apart.
When you figure the speed with which your parts move (remember at 9000 rpm, your valve open and close 75 times per second) the valve spring surges like a cylinder full of water. Controlling that surge with high frequency, anti-resonance spring materials such as the ovate wire used in beehive springs is a good thing.
Resonance can also be dampened by installing springs that when compressed are close to bind. The tighter the coil is to this point, the more stable it becomes. To this point, shimming up a shorter spring can actually be a performance improvement over using a spring, which has a higher installed height.
“The height of a spring before it is installed has no real significance to its performance,” notes Griffin. “The most important determiner is the installed height. You never want to achieve coil bind as it can have devastating affects on your engine. But a shorter spring shimmed to the proper height will help the efficiency of your engine. It is true that nearing coil bind there are frictional losses, but I’d rather have the increased spring stability any day.”
Bigger is Better?
With the ever-increasing number of beehive springs available, the question of going to a larger spring, bigger than what will fit in the stock valve spring seat can be a question. The key here is to ask a valvetrain expert. If they determine that your cylinder head requires a larger valve spring, they can suggest a spring and spring seat cutter, which can be used to provide the correct clearance for your application. Regardless of your specific application, beehive springs are probably a good item to consider as they offer a number of potential improvements over conventional springs in some applications.