I don't have time for a drama debate. Someone asked for real-world info on beehive springs, which I provided. I noticed that the one person who was calling other people names and rubbishing the idea of beehive/conical springs was the same person who didn't appear to even know how valve springs worked, let alone had any real experience with them. Thinking that seat pressure rides the cam lobe "continuously" proves this (hence my point).
So caveat emptor. Listen to the people who have used them, or listen to those who haven't. But name-calling is uncalled for – especially by those who do not appear to be in a position to call names.
And the fact that three of the people here arguing the merits of beehives all happen to be from Australia (which I have only just noticed myself) is simply a coincidence. Tarring an entire nation because you got called out simply shows what type of person you are.
Aftermarket head manufactures put budget "one-size fits all" springs in their heads because they know that many engine builders will remove them and replace them with their own springs matched to their choice of cam. Even "premium" head manufactured do this.
There are many advantages to running beehive/conicals, and I'm not about to list them all, but here are a few:
Rocker-retainer clearance
Longer component life through reduced weight and spring pressures (think cam lobs, valve seats, reduced lateral loads on valve guides etc)
Less heat
Reduced harmonics with better valve control
Reduced cost of complimentary components – no need to use to Ti retainers/valves or heavier rockers/pushrods etc where sprung weight can be reduced with the beehive spring and smaller steel retainer
Reduced complexity and set-up time/cost (fewer moving parts = fewer things that can break)
On the subject of single vs double springs, having a double spring is no guarantee of saving your piston and valve if a spring breaks because if it happens at high rpm, the inner spring and/or damper are not going to control the valve, which is likely going to hit the piston anyway.
But don't listen to me, listen to those who design and build these things for a living:
“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.”
Beehive Springs Sound Great, But Will They Work For You? - EngineLabs