HOW TO FIGURE OUT WHAT THE
INSTALLED SPRING HEIGHT SHOULD BE:
Spring Loads
Solid Height + .060*
Solid Height + .560*
Shovel
350 lbs
160 lbs
Evolution
350 lbs
210 lbs
*Andrews Products springs
Using both top and bottom collars, place spring
assembly in a small vise and close the vise until the outer spring is
solid. Be careful when compressing springs in a vise!
Now measure the distance between spring lands as
in diagram and write down the number for later use. This is the Solid
Height.
Calculate INSTALLED SPRING HEIGHT (min.) as
follows: INSTALLED HT.= Solid Height + .060 + Max. Valve Lift
Max. valve lift can be taken from catalog figures.
For example, max. valve lift for an EV59 cam is .560.
For an EV51 cam, using Andrews Products springs
and collars; INSTALLED SPRING HEIGHT = 1.190+.060+.510 = 1.760
This technique will work for any cam and spring
system as long as measurements are carefully made.
At time of installation, make sure that .050
(minimum) clearance is present between top of valve guide and bottom of
upper spring collar at maximum cam lift.
"Solid height + .560" (diagram at left) refers to
spring forces when the valve is seated. (.560 is an assumed spring
travel).
