I guess there is always the bigger/more is better mentality, so it is easy for some to believe that 2 springs are better than 1. However in this case less is more.
For my first few Dmax cylinder head builds I used dual springs. Actually they were aftermarket Toyota springs, it was all that was commercially available to fit the Dmax package at that time. There were some small block Ford beehive springs out there, but none with the amount of pressure/rate I feel we needed to control our valve train, given the increased boost and rpm. I could have stayed with the dual setup, but I felt there was a better solution to be had. A single beehive spring, with the same pressure as the duals but with considerably less mass. Leveraging my prior relationship with the valve spring manufacturers (FYI, the cam companies don't make valve springs) I designed a spring just for the Duramax and now have them built specifically for SoCal Diesel, usually in runs of 5,000 pcs. A premium steel wire that is ovate, not round.
I did a considerable amount of research into valve springs and valve train assemblies in the mid 1990s. This research and the products that resulted from it, constituted the basis for my first U.S. Patent. #5546899. This research continues to this day.
In a nutshell, valve springs have mass, as does the valve, retainer, keepers, pushrods, rocker arms, lifters etc. More mass in the valve train requires more spring pressure to control this mass. More spring pressure results in higher wear of the entire system.
The answer is to add enough spring pressure to control the valve train without adding any additional mass. In fact reducing mass would have the same affect as adding spring pressure as far as control goes, without the additional wear.
Stock LB7 spring and retainer is 86.2g.
Stock LLY/LBZ/LMM spring and retainer is 80.5g.
Dual spring assembly with a Titanium retainer weighs approx. 84.5g.
My beehive spring with the same pressure as the duals and Titanium retainer weighs 55.5g. This represents almost 35% weight savings over the duals.
As you can see the dual spring system will float the valves far earlier in the rpm range than the beehive system, because the additional mass of the dual spring requires far more pressure just to control it's own mass.
This trend of lighter mass, more efficient valve springs is being followed in all forms of motorsports racing.
The GM LS series of engines is a perfect example of production engines using the beehive spring concept with great success.
Comparing pricing, our kits feature 32 springs, 32 retainers, 32 valve seals, and 32 hardened OD spring cups which replace the cheezy sheet metal factory shim.
As far as practical application goes, our springs have seen 300mph at the Salt Flats, 180 mph and 7 second blasts in the 1/4 mile and countless 5-6,000 rpm sled pulls and many 1200hp dyno pulls. I'll let you draw your own conclusions from there.................
Hope this helps,
Guy
