S&S Cycle Valve Spring Kits for 1984-2004 Big Twin & 1986-2003 Four-Cam (90-2077 and 90-2078) - Manual (Page 3)

E. Repeat Steps A-D for remaining valves and record all
measurements. Be sure to keep track of all parts during
assembly to assure they are installed in same location
and with same valves clearances were measured with
4. Adjust installed spring height for all valves to 1.800” ± .020”.
If spring height is too high, place shims under lower collar to
achieve correct spring height. Shims are available from S&S
®
and local sources such as automotive parts houses. If spring
height is too low, grind valve or valve seat, or machine
bottom of valve spring pocket to achieve correct spring
height. Special valve spring pocket cutting tools are
available from various tool manufacturers.
NOTES
●
Installed spring height is same height as outer valve spring
when valve and spring are installed and in closed position.
Correct installed spring height for S&S #90-2077 and #90-
2078 is 1.800” ± .020”.
● For race and similar applications, experienced engine
builders may elect to shim valve spring assembly to installed
height less than 1.800” if cam with less than .640” valve lift
is used. In such cases, installed height should be not less than
1.170” + valve lift ± .020". For example, with .500 lift cam,
installed height could be shimmed to 1.170” + .500”, or
1.670” ± .020”. In such cases, spring pressure and valve train
wear will increase significantly. Engine builder assumes all
responsibility for installing springs at height other than
1.800” ± .020”.
● Installing springs at height less than recommended
dimension will cause rapid spring fatigue resulting in
possible engine damage. Engine should be frequently
disassembled for spring tension measurement.
● Installing springs at height above recommended
dimension will decrease spring tension resulting in
possible valve float and engine damage.
● Failure to establish required clearances may cause valve
seal failure and other, more extensive engine damage not
covered under warranty.
Valve spring assembly is under considerable tension when
compressed and is potentially dangerous. Wear eye
protection and take due caution when checking for coil bind
and during installation. After assembly, carefully strike tip of
valve stem with plastic hammer to insure that keepers are
seated. Direct spring assembly away from face and body
during this procedure.
5. Observing previous warning, check for coil bind as follows:
A. Place outer spring in vise or spring checking device and
carefully compress to 1.800” - valve lift - .060”. Using
.630 lift cam, for example, compress spring to 1.800” -
.640” - .060”, or 1.100”.
B. Measure clearance between adjacent coils. Minimum is
.060”. If clearance between spring coils is insufficient, a
different spring pack or cam with less lift must be used.
C. Repeat procedure for middle and inner spring for each
spring assembly.
6. Install valves and valve springs in heads. Install all S&S outer
springs with O.D. chamfer toward top collar. Be sure valve
guide seals are in place. Install middle and inner springs
followed by top collar and keepers.
NOTE - Installed height should be the same for each spring
assembly.
7. Confirm that rocker arm does not contact top collar. This is
most likely to occur when valve is fully closed. Clearance
should be at least .040”.
8. Confirm rocker arm to rocker cover clearance.
A. Install pushrods and rocker assemblies. Adjust pushrods
per manufacturer’s instructions.
B. Place thin deposit of clay or putty on inside of top rocker
cover directly above pushrod and valve spring areas.
C. Install top cover and rotate flywheels two complete
revolutions (720°).
NOTE - Do not force engine if resistance is encountered. Instead
remove top cover and determine cause.
D. Remove top cover and examine clay for indentation
caused by rocker arm. Thickness of clay beneath
indentation should be at least .060”. Carefully remove
metal from cover or rocker arm to obtain correct
clearance.
NOTE - Remove minimum amount of metal needed for correct
clearance. Care must be taken not to break through rocker covers
or alter rocker arm heat treatment by overheating while
grinding. Oil is supplied to top end through pushrods and rocker
arms, so it is also important not to disturb oil passages.
3
CAUTION
WARNING