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Pete Twissell
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Hugh Jörgen
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Original Post (Thread Starter)
Gold Star Engine Rebuild: Rocker Box #811324 06/03/2020 3:07 PM
by Magnetoman
Magnetoman
Late-ZB and BB Gold Stars as well as B33s adjust valve lash using variable-length tappets at the crankcase mouth, while CB, DB and DBD Gold Stars use eccentric spindles ("rocker fulcrum pins") for this purpose. Despite this, as the next figure shows, both types of rocker boxes are quite similar.

[Linked Image]

Assembling a rocker box is relatively simple. Although the illustrations in this thread are from a B33 rocker box I note where CB and later Gold Star models differ. The assembly procedure will assume you are starting from completely separate parts, so to disassemble a rocker box you would begin at the last step and work backwards.

Supplies needed:
-- Assembly lube
-- Loctite 262 (red, high strength)

A. Inspect the components to be sure you have the correct ones.

-- The circumference and operating arms on Gold Star rockers are ground to make them lighter than their B33 counterparts. For example, a BB Gold Star Inlet rocker is ~155 g (~165 g for a DBD) vs. ~180–200 g for a B33. However, even without weighing a rocker, if the casting number is still visible it is not from a Gold Star.

-- The exhaust rockers of late-ZB and BB Gold Stars and B33s have a drilled passage at the pushrod end and a hole at the valve end to bring oil to the cap of the pushrod and the valve tip. Both holes are present on Gold Star intake rockers as well, but B33s only have the oil passage at the pushrod end. Starting with CB Gold Stars the ball and sockets were reversed and the oil passage at the pushrod end was eliminated and replaced with a hole directly over the pushrod.

[Linked Image]

-- Ensure the oil holes at both ends of both Gold Star rockers (and only at the pushrod end of a B33 inlet rocker) aren't blocked.

[Linked Image]

-- Rocker spindles ("rocker fulcrum pin") on CB, DB and DBD Gold Stars (bottom) have a hex head at the oil inlet end to operate the eccentric shaft while those on late-ZB and BB Gold Stars and B33s (top) are plain.

[Linked Image]

-- The spindles should have a diameter 0.5605" in order to provide 0.002" clearance in an unworn 9/16" rocker arm. Insert the spindles in the lifters and check that they turn without any feeling of resistance.

-- Clean the inside of the spindles and make sure the exit hole isn't blocked. Not all exit holes are in the same position, but this has no effect on function.

[Linked Image]

-- The banjo bolts for attaching the oil feed manifold to the spindles are not interchangeable. The bolt on the inlet side (65-317) has a much smaller hole than the one on the exhaust side (65-318). Make sure neither one is clogged.
Liked Replies
Re: Gold Star Engine Rebuild: Rocker Box #811331 Jun 3rd a 03:22 PM
by Magnetoman
Magnetoman
D-4. With the spindle barely peeking into the cavity, insert the spring and washer, which will hold themselves in position as you begin to insert the spindle through them. Note that if the open end of the spring isn't in the right orientation when you insert the washer (top) it's easy to get the washer trapped between coils (bottom) where it will block the spindle from being inserted.

[Linked Image]

D-5. Once the washer is correctly positioned it still will require manipulation with a small needle-nose pliers to get the washer over the sharp step near the threaded end of the spindle. However, after the spindle is past that point it will be easy to continue inserting the spindle.

[Linked Image]

D-6. If in Step D-1 you attached the thrust washer to the cavity at the other end of the rocker box using grease, and if it didn't fall out and need to be retrieved, continue pushing the spindle until the threaded end emerges from the rocker box. Since it is a light press fit it might require tapping the end with a soft hammer before the threads emerge.

However, at this point in the assembly process an alternative to using grease as mentioned in Step D-1 is to open a gap between the rocker and housing by pulling the rocker against the spring and use a small needle-nose pliers to insert the thrust washer. The washer only needs to be partially in place before you let the spring push the rocker against it. The rocker will keep the thrust washer from falling while you then manipulate it into the cavity, after which you can continue pushing the spindle.

[Linked Image]

-- If the thrust washer is out of position, or the spindle is misaligned and can't be pushed out the exit hole in the rocker box, viewing the spindle from the hole in the housing will allow you to correct the problem.

[Linked Image]

D-7. The spindle is a loose press fit in the rocker box so it will require a few taps from a soft hammer to fully insert it, after which the nut and washer can be attached and tightened.

D-8. The other spindle is installed in the same way.

-- The internal cavity of each rocker assembly has an open volume of 3 mL (6 mL total) that needs to fill before oil can get to where it needs to be. That volume, plus that of the supply line, means the oil pump would have to work for a while fill them, which is why you should prime the lines and cavities before starting the engine for the first time after a rebuild.

[Linked Image]

---------- [End rocker box rebuild] ------------
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