dtroike

iTrader: (4)

I am using a set of K-motion K800 valve springs and after checking them they have lost about 20-30 lbs at 1.79” and at 1.13”. When I checked them new they were 495-500 and 195-200. Now they are 470-475 and 170-175. I am in the process of switching to a cam with slightly less aggressive lobes and they pressures they are at now are about what im looking for. Since they have already lost some pressure will they level off or will they get worse faster? What is a normal amount of pressure to loose on a spring that is still good? Are these good springs? Right now they probably have about 600 semi hard street miles on them, maybe 60 1/8 mile passes, and they are 3 years old.

A.R. Shale Targa

iTrader: (2)

Springs will normally lose 10 percent after the first few heat cycles
The key to your setup working will be properly shimming the springs within .060" of
coil bind at full lift.
Light valves, retainers, and stout pushrods are all beneficial

Gray86hatch

iTrader: (83)

My lunati dual spring never lost more than 10psi over 5000 miles.

Tim

v8pwr

iTrader: (19)

Your reduction in rate seems ok. It depends upon the spring and application. Good spring with easy life should only have minor loss. Good spring with a hard life will show more. A lesser spring is made with economical materials & processing and shows fatigue sooner while a high end spring is made from better materials & processes to deal with more stress.

dtroike

iTrader: (4)

[QUOTE=A.R. Shale Targa;18500151]Springs will normally lose 10 percent after the first few heat cycles
The key to your setup working will be properly shimming the springs within .060" of
coil bind at full lift.
Light valves, retainers, and stout pushrods are all beneficial[/QUOTE

Thanks. They are shimmed at .060 to coil bind and have the correct locators. Using manton 11/32 .120 wall pushrods, yella terra ultralights, LS3 intake valves and standard TFS stainless exhaust valves.