 |
 |
|
Checking spacer measurement. |
Installing shaft end spacer. |
|
 |
 |
|
Installing rocker arm shaft. |
Installing inner spacer. |
|
 |
 |
|
Installing shaft and aligning set dimple. |
Setting the rocker shaft. |
|
|
One of
the reasons for the procedure was because the V-twin camshaft was not
centered in the engine. The angle of the front exhaust push rod leaves a
lot to be desired. In early testing the pushrods with the 1/4-inch
hardened adjusting screws would snap whenever they felt like it. This
occurred not only on 4-valve engines but any V-twin that could twist up
revs. The
industry has responded to this with a new breed of pushrods with larger
adjusting screws. I am presently testing the Taperlites made by
Rivera Engineering with good results. Now for
the most overlooked part of this assembly and probably ninety percent of
the problem of noise, the rocker arm end play. When the cam raises the
pushrod and moves the rocker arm down on the valves, it also sends the
rocker arm away from the pressure of the pushrod. When the push rod goes
down and the springs push the valves shut, the rocker arm goes to the
opposite side. There's
your noise, but the fix is easy. The process to check is: First
the rocker arms cannot have any pressure on them from the pushrod or the
springs. They must be able to move back and forth freely. In most cases,
they can be checked by removing the rocker cover and positioning the cam
properly. If you have to remove the rocker boxes from the engine, do so.
Push the rocker arm as far as you can one way or the other Place a feeler
gauge between the stainless steel spacer and the rocker arm if the
clearance is over .008 (eight thousandths). For future reference measure
and record the end play of each rocker arm. You need to remove the rocker
shaft and arm to remove the spacers. THE
ROCKER BOXES MUST BE REMOVED FROM THE ENGINE
There is a set screw on the bottom side of the rocker box that holds the
shaft in place. Remove the set screw with a 1/8-inch Allen wrench. Give
some thought on how you want to do the following as the shaft is usually
hard to remove It also must be pulled straight out and without damaging
any of the other parts. I got frustrated at most of the systems I had
available and designed my own rocker shaft pulling tool back in '91. You
may want to try and make something similar. There is
a 1/4 x 20 thread tapped in one end of the rocker shaft. This is used to
pull the shaft out of the rocker box. Remove the shaft completely and lift
the rocker arm and the two stainless steel spacers from the rocker box.
The rocker arms are numbered for identification and though they may appear
to be the same, they are not. You may even want to put your own markings
on it so that you return it to its proper position. This is
a good time to check the rocker shaft and bushings for wear. Of course,
they should be replaced if worn. Parts are available, but bushings must
be line honed If they are replaced. Measure
your stainless steel spacers. If they are original, they should measure
.032 (32 thousandths). Take the end play measurements you previously
recorded, start with any shaft that you want to, subtract .004 (four
thousandths) from that measurement, and then divide that measurement by
two. The resulting number is what has to be added to that shaft's spacer. SPACERS MUST BE EQUAL IN SIZE TO EACH SIDE OF ARM SO AS KEEP SWIVEL FEET ALIGNED WITH VALVE STEMS Spacers are available 032/034/036' 38/40
Once you have figured out what set of spacers you need, place a light coat
of grease on housing spacers, shaft, and rocker arm bushings Insert the
shaft just enough to install one spacer. Then carefully place rocker arm
into the rocker box and shaft into rocker arm. Turn rocker box on end with
shaft end facing up. Carefully slide other spacer into position while
holding rocker arm up. Push the rocker arm shaft in just enough to pass
through washer and start into box. Do not go too far
|
||
