Building up the rocker boxes or how to keep the noise down
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So what's the big deal about putting a set of Shovelhead rocker boxes together? After all just put the rocker arms and shafts in and you’re done with it...right...? Not so fast bunky.

First off let me say that I think the design of this top end is, well, less than optimum. 

The top end of a Shovel has been known to be a little noisy. 
This article will give some tips on how to quite down the rocker noise and in the process add life to your valve train.

Warning....
Let me say this right away. There are kits out there that use spring or wavy washers to take up the end play in the rocker assemble. DO NOT USE THEM.
I tried these years ago and after a short time the front exhaust rocker started making a hell of a racket. I pulled the head, took off the rocker box, and found pieces of the wavy washer inside the box and head. I took the box apart and very carefully inspected the head. I found a lot of pieces and put them together like a puzzle on my bench. I was relieved that I had found them all and nothing got into the motors innards. I did a little research and found I wasn't the only one. Many people have had the same thing happen with much less favorable results.
Shim with flat shims only.

Now on to the tech stuff...


Here are the new boxes fresh from the chrome shop. It only took a month to get them out and back. Sheeesh....
The shop that did these did a great job although I have no idea who it was. I took them to my local Harley dealer, were I got the best price, and they

sent them off. I did look at examples of their work first before handing them over.


Bottom side.
BoxBottom.jpg (31675 bytes)

Screw.jpg (37171 bytes) I counter bored the screw holes to give the boxes a cleaner look. Chrome toppers will finish this off nicely

OldParts.jpg (39296 bytes) These are the old parts from the top end most of which I'm not going to use. These are the only parts I'm using from the old installation. The end nuts, washers, end caps, and some of the shims. SavedParts.jpg (79142 bytes)

AllNewParts.jpg (57251 bytes) All the new shiny parts ready for build up.
Make sure they are very clean and free of grease and oil. You don't want anything throwing off your measurements.
Ok, step one.
Insert the rocker arm into the box as shown. It's easy to figure out which goes were. There are only to configurations of rockers
InsertRocker.jpg (58223 bytes)

LargeWasher.jpg (40162 bytes) Next insert the large spacer between the rocker arm and the box. Now insert the rocker shaft through both parts until it is seated all the way in.  InsertShaft.jpg (47927 bytes)

EndPlug.jpg (41948 bytes) Install the end cap screw but
d
on't user the end cap seal at 
this time
.
Torque the rocker assembly to 18-24 ft lbs. TorqueRockerShaft.jpg (53283 bytes)

MessureGap.jpg (43302 bytes) With your finger pull the rocker arm back away from the large spacer and measure the gap between the rocker arm and spacer with a feeler gauge. The book says .004-.025 of an inch and this is where the noise and wear come from. With a wide gap between these parts, .008 or greater, the rocker arm moves back
and forth on the shaft causing the top end noise. To fix this you add shims to the assembly to close that gap up. In this case the gap was .011.

MessureShim.jpg (33840 bytes) Going to my pile of saved shims I find one that is .005 of an inch to place in the stack of parts.

InsertShim.jpg (52414 bytes) Remove the capture nut from the end of the rocker shaft and pull the shaft partially out. Use a magnetic screw driver to insert the shim between the rocker and spacer. The reason is the hole in the shim is the size of  the bearing surface. 
Be careful and hold the shim up with the magnet until the shaft is completely seated.

If the shim falls down onto the narrower part of the shaft to will get caught between the shoulder of the bearing surface and the spacer creating an even larger gap.   BadShim.jpg (23885 bytes)

CrushedShim.jpg (27509 bytes) If that happens you wind up with shim that looks like this.
Note the crushed portion on the ID. When this happens not only do you get no benefit from the shim and the shaft shoulder won't seat against the spacer. The result will be an oil leak were the shaft exits the box
 
Of course you know I did this for demonstration purposes. ;) 


GoodShim.jpg (25509 bytes) This the place the shim should be when you get it all together.

GoodShimFit.jpg (29222 bytes) This is the configuration your looking to achieve. The shim will be on the bearing surface when all the parts are seated and torqued down.

RockBoxDone.jpg (55440 bytes) All done.
They'll never be this clean again...or at least until the next time I decide to customize the bike again 8-10 years from now. 
When you get the assembly back together, torqued down, and you’re satisfied the shim is correctly located re measure the gap again using the same technique as before. If you get .004-.008 then your golden and can move on to the next one.

Finish all four rocker assemblies  before you take it all apart for lube. Do this one assembly at time and take your time. Use whatever assembly lube you're comfortable with. 
When you get both boxes together you are then ready to mount them on the heads.
That will be another chapter in the ongoing saga of Kevin's 81 shovel project.  


Copyright Notice: The Author of this work retains full copyright for the written material on this page. Permission is granted to make and distribute verbatim copies of this document for non-commercial private research or educational purposes provided the copyright notice and this permission notice are preserved on all copies.
Copyright 2004 Kevin J Riley

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