Originally Posted by 4 Jaw Chuck
I have looked at valve springs under a strobe on a running engine and the only time they ever "surged" was at valve float rpm.
They belong on big rig diesels (with all their associated vibrations and loading), not street autos.
Sorry guys but I have not seen one engine builder that uses them because they fill the oil with metal particles from all the rubbing.
They don't come on any modern automobile engine I can think of? They increase spring pressure instead which controls harmonics far better than any dampener, by increasing spring pressure you raise the rpm where harmonics occur.
It just doesn't get any simpler than that. If they were so great every aftermarket spring supplier would be putting them on their HP springs.
I think the point that's getting overlooked is that he is not using a modern spring with ovate wire, beehive contours, and differential winding, he using old spring technology which is rather dependent upon some kind of damping whether that's flat wound friction dampers or counter wound secondary springs.
They hardly put any metal into the oil, they wear very slowly over a long time. Increased spring pressure, while a panacea to many dynamic problems introduces high wear in all the loaded points of the valve train as these higher spring forces must be overcome by every component in that chain every time the lobe pushes up on the lifter. not like that doesn;t put metal particles in the oil.
All he's got to do to get off this hook is to belly up to the bar and order a nice set of Comp beehives. Then we can all go home trusting that the future will be Rosy.
The reason you saw the valve springs surge at valve float RPM is because that surge is the major cause of valve float when it happens, that's the valve float RPM.