Valve Spring Life - Duals vs. Beehives
Valve Spring Life - Duals vs. Beehives With a TSP228R cam, would you expect valve spring life to be greater using PRC 0.650 springs or PAC 1211x 0.625 lift beehive springs?
Your asking a question I also have. I have an opinion but no experience so give more weight to the other opinions you get.
Define spring life: either the spring breaks or the spring loses a percent of it's pressure. What % that is, I do not know.
On a Dual, if one spring breaks, say the outer, the inner spring will keep the valve from contacting the piston up to a certain RPM. Beyond that RPM there will be contact and could result in a bent valve, causing a damaged seat and damaged piston. Possible disloging of the valve locks from the retainer and a dropped valve.
On a Beehive, if a spring breaks there WILL be piston contact with the same results.
A Dual controls harmonics (spring surge) by having the inner spring contacting the outer, like putting your hand on a ringing cymbal. This interferance fit causes heat and that heat is controled by oil on the springs.
A Beehive controls harmonics by varing the spring rate. Having the top coils smaller and stacking coils as the spring is compressed. This stacking of coils also creates heat but much less. That heat is controled by oil on the spring.
Since heat and harmonics, along with cycles and stress determine life, it is my "guess" that the Beehive would last longer.
I hope the others here can give us the answers we need to make a informed choice.
Define spring life: either the spring breaks or the spring loses a percent of it's pressure. What % that is, I do not know.
On a Dual, if one spring breaks, say the outer, the inner spring will keep the valve from contacting the piston up to a certain RPM. Beyond that RPM there will be contact and could result in a bent valve, causing a damaged seat and damaged piston. Possible disloging of the valve locks from the retainer and a dropped valve.
On a Beehive, if a spring breaks there WILL be piston contact with the same results.
A Dual controls harmonics (spring surge) by having the inner spring contacting the outer, like putting your hand on a ringing cymbal. This interferance fit causes heat and that heat is controled by oil on the springs.
A Beehive controls harmonics by varing the spring rate. Having the top coils smaller and stacking coils as the spring is compressed. This stacking of coils also creates heat but much less. That heat is controled by oil on the spring.
Since heat and harmonics, along with cycles and stress determine life, it is my "guess" that the Beehive would last longer.
I hope the others here can give us the answers we need to make a informed choice.
Heat management is a big one, but I think there's more to it, such as the size of the wire, the aggressiveness of the helix in which it's wound, surface treatment, and the composition of the steel itself.
Most people here are only going to be able to give you a WAG (wild *** guess).
Most people here are only going to be able to give you a WAG (wild *** guess).
My suggestion if you don't have the cam yet is to get a cam with mild cam, not a 228r which uses aggressive XE-R cam lobes lobes if your concerned about longer valve spring life. If you already have the cam then I'd run dual spring since you can usually get higher spring rates at seat height which will allow better control of the XE-R lobes. To further increase valve spring life make a permanent habit of letting the car warm up (at least half way) before you take off driving since cold valve springs are more likely to be damaged since they're more brittle when cold. The PAC 1219X beehive valve springs would be a better option than the 1211X spring since they offer a higher 145 vs a 130 spring rate at seat height. Now as far as whether beehive or duals will last longer I couldn't really say.
Maybe you can get PAC Racing to chime in..?
Maybe you can get PAC Racing to chime in..?
Nope I have not purchased the cam yet. I know the 228R cam has aggressive lobes. It was an example for the sake of discussion regarding the springs. Cannot decide on the specs I want yet. But I am thinking I will stick with the PRC .650 springs already installed in the stage 2.5 5.3 heads and get a custom cam from EPS. I understand that they have nice lobes for valvetrain stability and life, as well as the alloying in the steel has better characteristics (surface hardness, wear resistance, ect).
Now I just need to select my specs. I want to improve power everywhere. I am not installing aftermarket rod bolts so I will never spin this thing over 6500rpm. Redline will be set at 6400rpm. Additionally its the daily driver. Needs to idle and drive at low rpm well. I can compensate for this alot with my tuning, yes im good lol. Want something to compliment my heads as well, which I calculated will be ~11.4:1 CR with its 59cc chambers.
Now I just need to select my specs. I want to improve power everywhere. I am not installing aftermarket rod bolts so I will never spin this thing over 6500rpm. Redline will be set at 6400rpm. Additionally its the daily driver. Needs to idle and drive at low rpm well. I can compensate for this alot with my tuning, yes im good lol. Want something to compliment my heads as well, which I calculated will be ~11.4:1 CR with its 59cc chambers.
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I know for a fact that they're extremely light weight. The disadvantage of duals was that your valve spring would weight more, but you earned much more seat and open pressure. The conical is lighter than a beehive, with seat pressure comparable to a dual. I cant remember the information on harmonics.
I know for a fact that they're extremely light weight. The disadvantage of duals was that your valve spring would weight more, but you earned much more seat and open pressure. The conical is lighter than a beehive, with seat pressure comparable to a dual. I cant remember the information on harmonics.
It's the open pressure that is comparable to a dual, over 400lbs but the seat pressure is 130.
I'm trying to decide between 7228 Conicals and BTR .660 Platinums. Thinking about a LXL 230 single pattern on a 111 +0
Last edited by squalor; Nov 12, 2014 at 02:30 PM. Reason: added video
I know for a fact that they're extremely light weight. The disadvantage of duals was that your valve spring would weight more, but you earned much more seat and open pressure. The conical is lighter than a beehive, with seat pressure comparable to a dual. I cant remember the information on harmonics.
As far as the life on beehive or dual, it all depends on your application. Remember basically all OE is beehive and they can see hundreds of thousands of miles.
What you are not told about when you reach rates this high on a single spring, are the stress levels the spring is seeing. Low rate=low stress, high rate=high stress. This is why duals tend to have higher rates than singles. We offer a conical spring, have been for over 5 years but it is marketed as a BBC drag race only spring.
As far as the life on beehive or dual, it all depends on your application. Remember basically all OE is beehive and they can see hundreds of thousands of miles.
As far as the life on beehive or dual, it all depends on your application. Remember basically all OE is beehive and they can see hundreds of thousands of miles.
I'll be using them on the cam that is in my TA. It's a 235 degree single pattern cam but I don't remember the lobe on it. I've been traveling for work so I haven't really had a chance to make any progress just yet.
Seems that the conical shape dampens the higher order harmonics more effectively which minimizes surge/float. Kinda like an ATI super damper as compared to an oem rubber bonded pile.The micro/media polishing or surface enhancing apparently serves at least two purposes. First by reducing microscopic imperfections which could cause a breakage. Second by being smoother, the oil runs/drains off of it faster which removes heat (btu) quicker and extends the lifespan. Friction causes heat and the faster you move a strong spring, the more heat it produces. IIRC @ 7000 rpms each valve opens and closes like 58 times per second. Pretty sure a 9000 rpm NASCAR engine is 87/sec. Quite insane what we ask of them !!