Oops that is my mistake. I was thinking of the PAC 1518 that was rated for .650 lift.

 

What exactly is the argument to run a single spring???

I mean seriously.....what does it do that a dual wont do except remove the safety net under the high wire act you may as well enlist in with a single.

You most certainly have warning with a dual when one of the coils break....noise is typical as is the engines more notable struggle to reach the RPM it did before.

If your not in tune with your combination and choose to avoid looking into new valvetrain noise or the fact the engine isn't quite running as well (you wont have good valve control and the same power from the cylinder with the broken dual spring) it certainly wont save you because at some point you will break both coils but with a single, barring a heap of luck and good fortune, if it breaks that valve only has one direction to go and it aint pretty. It can literally cost you an entire engine including the heads when the shrapnel from the piston breaking and valve mulching goes everywhere. You can reuse your intake after you clean all the bits of metal out of it.

So I ask again.....why even think about running a single when it offers no competitive advantage to a dual and comes with a significant amount of added risk??

Yes....a dual doesn't guarantee you will be OK.....especially if you ignore telltale signs of a problem, but you at least have a very good chance of catching it versus a single spring breakage which is highly likely to immediately create catastrophic engine failure in the event of a breakage....and ALL parts break....I don't care who's name is on the box and what was done to them. We don't live in a perfect world....**** happens....try to help yourself by thinking this thru a little more.

Plenty of good reliable dual springs out there to choose from....I will be launching my own line of spring kits soon (mainly using PAC as my supplier) and note I will only carry dual springs. I wont even sell singles.....I'm just dead set against them unless my customer simply insists and he will still hear a rash of %$#& from me before I ship them to him

-Tony

 

It's lighter and cheaper? lol All I got.

 

The single springs (beehive and conicals) are lighter and have better harmonic characteristics. That results in better power and a more stable valvetrain.

Hot Rod saw some nice top end gains when they switched from a dual spring to a beehive with ~200lbs less open pressure.

What You Need To Know About Valvesprings

"Even on a relatively mild 406ci small-block Chevy with a hydraulic roller cam, a spring incorporating the latest technology can make a big difference. Westech Performance tested a traditional Comp Cams dual spring with damper (PN 954) against one of Comp's new single beehive springs (PN 26918). The 954 developed 210 pounds on the seat and 523 pounds open, compared with the 26918's 130/318-pound specs. Both springs were installed with titanium retainers and locks, yet the beehive combination was still 52 grams lighter. If the engine's steel valves had been replaced with titanium valves instead, the weight savings would have been just 40 grams.

Overall peak output was virtually the same: 418.4 lb-ft for the 954 versus 416.9 lb-ft for the 26918, both at 4,800 rpm; and 418.2 hp versus 419.3 hp for the 954 and 26918, respectively, at 5,800 rpm. Average output throughout the 2,500- to 7,000-rpm test range varied by only about two numbers. But above 6,500 rpm, the difference was huge: The new-tech 26918 effectively extended the engine's rpm range, proving to be worth 15 to 36 hp and 12 to 28 lb-ft on top. The stiffer 954 did produce more low-end torque because its higher loads were actually bending the other components, effectively decreasing duration at the valve." -Marlan Davis

 

There are pros and cons to either system, the beehive springs are lighter, the dual springs are more durable.

We tested our dual Platinum springs versus some popular beehive springs back to back on a engine dyno and they both made the same power, so there's no real world power advantage in a beehive spring that I've seen. Although we control the spring rate so the maximum open spring pressure is 400 lbs or less.

 

Are Hot Rod's results not real world? They made the same peakpower but the beehives held out longer, so average power was increased.

I can see an argument that different applications would see different results though, but it shows there is a viable advantage to single springs in at least some applications.

 

If you run a dual spring with too much pressure (which causes friction and losses) and switch to a beehive that is ideal for your setup, then yes. You'll gain HP.

The rule of thumb is to have just enough spring pressure to control the valve. Not any more.

 

Exactly. With beehives, you don't need as much spring pressure because you don't have as much mass to control on the valve side of the rocker arm. Hot Rod saw a 50 gram reduction switching to beehive springs.

 

People don't take into account the entire weight of the system or the aggressiveness of the lobe when they slap **** together. There's a reason I run hollow-stem LS3s on my heads. It's 83g vs the standard Ferrea weight of 110g. That's significant. I also run Ti retainers which help with weight. So do the stock rockers.

The duals are heavier, but when you look at the system, you run what is needed for all components. Could I pick up power switching to Beehives? Maybe, but I'm not running a ton of pressure with PAC 1904 springs as the system doesn't need it to be effective.

I'd rather run the duals and have some margin of safety than pick up 10HP at 7000 RPM.

 

Dude, that comparison is a bit flawed. 523 pounds of open pressure? Kip Fabre would tell you that's abusive. He advised me to aim for 380 open pressure.

You would need 3/8 pushrods, probably thick walled, stout as hell lifters, and maybe solids. If the pushrod was deflecting, you were probably also pole vaulting the valve off the peak, which is dangerous also. And I hope the rocker trunnions were really stout as well.

But that's not "duals drool and beehives rule". That's "set your valvetrain up correctly. Use enough spring to control the valve." Maybe a touch of safety margin, but 523 pounds is way high.

 

Show me a test where the springs were at basically the same open and seat pressures and I'll start to consider it scientific.

 

The hot rod magazine comparison is garbage...who would actually compare a 210/523 dual spring to a 130/380 beehive on a mild setup? Lmao

A 150/380 dual should of been compared to the 130/380 beehive and I bet there would of been very little gains just as BTR pointed out. Jake also hit the nail on the head.

 

Amen....

I've also tested the singles and duals on the dyno....my experience showed the duals actually seemed to carry better past 6800.....under that RPM it was a lay over (no difference in power).....these were the 26918's versus the first gen 8019 AFR springs.

With the rest of the valvetrain properly set-up I have achieved solid roller style power curves on countless builds I have been involved in and offering (myself) and all the customers I helped the peace of mind of running a dual spring and having the safety net that goes with that choice.

And at the end of the day it is all about choice....for me it's a no brainer....besides what sounds sexy on paper (harmonics, lightweight, etc.), the singles IMO offer little real world benefit (my personal testing actually favored the duals), yet the risk factor increase is without question hard to argue with and very significant. Why would you risk (potentially) every dollar you invested in your engine even if it was worth some power? (which it isn't).

No thanks for me....I will take a pass and recommend to every client I help he or she do the same. While there are various high quality single springs on the the market that have good track records, I simply wouldn't take the chance as slight as it may be....its far to costly in the event your one of the unlucky ones that draws the short straw.

-Tony

 

I wholeheartedly agree with this post - I had a single beehive break on me, and the valve wrecked that head, broke a piston, which took out a rod and put a hole in the block. I'll never run anything but a dual spring again.

 

I've seen the opposite to support Tony's argument, an Australian Holden engine in a street car with a stupid mechanical roller camshaft at the time, 264 and 274 @ .050" and around .690" lift with K Motion dual springs, something like 200lbs seat and 600lbs over the nose from memory.

I found two broken outer springs on a teardown, both still held their form until the retainers were removed though. I'm pretty sure the last drive beforehand had at least a couple of 7000+RPM busts, no dropped valves and no engine damage.

Pure dumb luck for certain which I couldn't believe at the time but the only thing keeping it together as far as I could see was the inner springs.

Best wishes,
Jason.

 

https://ls1tech.com/forums/advanced-...-lift-etc.html
From the "Read me First" sticky at the top of this forum. This post is what made me want to run a performance beehive. This and Predator_Z success with PSI 1511ml springs.
LQ4-E39 I read your post, as well as others who used PAC beehives with XE-R lobes and broke a spring. I feel bad for your loss but I still feel Beehives have their place and feel the PSI beehive is a different case, a tougher spring. BTR must feel the same way or he wouldn't carry them. Another member here, Damien also agrees.
I bought PSI 1511 and am trying to make a combo around them. I have LS6 valves so that should help them live. I plan to get a Cam Motion stick with their smooth (55) lobes in .595/.578 lift and 223/230 112.5+1 , should be a easy cam that will help them live.
So the quote is, "so there's no real world power advantage in a beehive spring that I've seen. " If you search youtube for Comp Conical, their testing says something quite different.
Tony, if you are going to introduce a line of springs why not try to combine the best of both ideas ? A dual spring with conical shapes and smaller retainer.
Until then, maybe the title of the thread should not be singles vs duals but instead, When is it ok to use singles.

 

We found things on the spintron that didn't show 1 hp difference on the dyno. In my opinion a smoother trace on the spintron manifests itself in durability, but not necessarily in power.

Don't assume lighter components automatically equaling more power. A reduction in component weight (valves, springs, retainers) does not automatically equal a gain in power. If the lighter components allow increase RPM, then yes you'll make more peak power. Conversely if more spring pressure allows increased RPM, even though it may weigh more, again you'll make more peak power. Think for a moment about how many professional race teams use beehive springs.

I've made a lot more power in hydraulic roller applications by using less aggressive lobes and less spring pressure. Less spring pressure generally does mean more power, because of less parasitic loss.

I've also made more power with less lift because of that same parasitic loss. Anytime a valve is opened further, the power gained from opening it further has to exceed the power expended from opening it further, if it does not, then it's a net loss. That's a very important concept to understand. I wish more cam guys would actually do more back to back dyno testing so they can determine the point of diminishing returns, because everyone's setups would be making more power and be more durable at the same time. The assumption that more lift equals more power is one of the dumbest things that is circulating on the internet.

Rent yourself some dyno time and swap some springs and let us know what you find. I've done it, there was no difference in power between the beehive springs and our Platinum dual springs.

 

Can you guys post any data from some of your testing?

It's interesting that in the Hot Rod article, peak power didn't really change much but power after peak was increased. Anyone have any testing that showed similar results?

 

That's just it.....I don't think ANY application warrants the risk of a single. You do realize you are gambling with the fate of your entire build and all the money you invested for folks keen on running them for reasons that still escape me.

How many combo's have I designed for myself and my customers that most would agree make more power than an average build of similar nature? Alot....and every single one of them are running dual springs.....typically the upgrade AFR 8019 or one of the PAC 1200 series springs depending on the combo. None of these packages would have ran better or made more power with a single but every one of my clients (not to mention myself), can sleep better knowing they have the safety net of a dual.

The performance benefits of single versus a good lightweight dual are negligible at best to non existent (my testing actually showed duals being more effective at higher RPM) but the increase in financial risk and heartache is HUGE. Find me one person that had a single spring break that would ever go back to one....its just silly to consider.

Consider my posts on this subject as leading a horse (horses) to water.....whether you drink or this information sways you in any way is up to you. I know what I will be using as will my clients and that's all I can possibly expect to control. The information I'm very passionate about and spending the time to share is for all your benefit.

Regarding the test results, they were done a long time ago at Westech for AFR and I wouldn't have access to the information any longer but I give you my word the results Im sharing was exactly how things went down. After 6800 the power curve started showing some instability/light valvefloat where the dual springs curve was still smooth. Note both HP curves had rolled over and were on the decline but the single spring with its slight instability around 7K started falling of worse and the curve was more jagged.

-Tony

 

That would again be a flawed test. One advantage of the beehives is the ability to use less pressure to control the valvetrain. You would basically kick the leg out from under a beehive in a test of that sort.

Then you also have to consider what system of components you're asking the spring to control. An L92 with an LSK or XER probably will see better results with a dual spring and 450lbs. An LS6 with an HUC lobe may have the opposite results.

I don't have any time in the pits or engine shops of professional race teams, but I do know reducing valvetrain mass is the holy grail in most of them. I understand it doesn't necessarily mean more power, but it can allow an engine to make more power with the right combination of parts.

Besides the millions of OEM engines using beehives?

People selling beehives swear by them. People that don't sell them swear they're the devil. Who to believe?

There are a lot of conditions that can cause a spring to fail as I'm sure you're aware. Many times, it's not the fault of the spring. I guess if a customer has broken a single spring, then maybe they do need something more "idiot proof" and that's certainly a valid selling point for many enthusiasts out there. Chances are, whatever caused the single spring to break will cause the dual spring to break as well if left uncorrected.

If I'm not mistaken, I believe the dyno test in the Hot Rod article was performed at Westech as well and it shows the beehives having an advantage.