17611-48 Rocker Arm Bearing

[wideglide38]

Did the MoCo make the right bearing with "MB" cast on the top? I've always understood the "MB" bearings were after market. Thanks William

[T. Cotten]

Did the MoCo make the right bearing with "MB" cast on the top? I've always understood the "MB" bearings were after market. Thanks William

Later OEM intake blocks, William!

I've got fifty pounds or more of all kinds of blocks, if anybody needs them.

(Even several sets that I 'blueprinted' decades ago.)

....Cotten
PS: Has anyone risked aftermarket rocker arms? Thanks in advance,...

[wideglide38]

Cotten,
Thanks. After I posted, I found in a -58 parts manual part number 17611-48A. Not sure what changed for the 'A' revision. Good question about the aftermarket shafts as I'd be interested hearing what others have determine from use.
Thanks, William

[FNG1]

Hi Cotten, I went with STD heads and V-Twin rockers on my 51 EL stroker. I have not had any problems or been back in to it in 24000 miles.

[T. Cotten]

Wow, FNG1!

They even look like they were heat-treated by the same copper-dip process as the originals.

If Tedd's rocker arms are serviceable,.. then my pile o' worn blocks might be worth something?

Thanks!

.....Cotten

[FNG1]

You're welcome. Pics say it better than I could.

[T. Cotten]

I don't think I was quite correct, Folks!

Although I found rough-cast blocks as exhausts with smooth-cast as intakes on several machines, it may not have been the rule.

This pic shows both rough and smooth-cast blocks with oil holes for the intakes, and a smooth one without.

The bottom row shows variance in the angular oil gallery cut into the tops. The earliest block (found with the early rockerarm pushrod bearing insert) has none.

....Cotten

[wideglide38]

I wondered the purpose of the angular oil galleries on the upper bearing blocks. Is there a purpose to oil to a mounting stud/hole (i.e. no returns?)? Is “MB” is the name of a 3^rd party foundry hired by the MoCo or just an aftermarket company’s own mark? Thanks William

[T. Cotten]

If we are allowed assumptions, William,...

The early rocker assembly (rough-cast and the early arm cup) has no gallery, and the original design also included a copper seal under stud nuts (attached).

Please note in the '36-'48 Parts Book there are no intake oilers, but a curious 0259 washer, which I presume was the seal.

Its easy to imagine the galleries evolved if and when the early design showed problems.

....Cotten

[wideglide38]

Assumptions are plentiful today's world! haha In my '41-'54 parts manual, I see 18110-49 Intake Valve Oiler Gasket, qty. 2 (for the 18100-49 & 18102-49 oilers). The part numbers (18100-49 and 18110-49) appear incorrectly marked in my printing - see photo 1. Thanks for the image of the copper washers. William

[T. Cotten]

Gosh Folks,...

We are raising more questions than answers!

Was the 0259 washer copper? Was it the same as 18110-49 (or maybe 18100-49)?
What was its purpose either way?

Then why didn't we find them in later models, since the book lists them through '54 at least?

Why don't the Parts Books make at least a distinction for the blocks with the drool holes?
Shouldn't there be a Shop Dope on this? I bet somebody's got the literature, and holding out on us.

....Cotten

[T. Cotten]

The fossil record can be confusing, Folks!

So here's my orphan rockerblock collection, and it naturally raises more questions.

In the first photo, showing rough-cast blocks, note only the four on the bottom left have drool holes. My suspicion is that all early blocks were rough-cast, but the drool hole (which I found as intakes) was a production change, thus outnumbered.

Smooth blocks on the right in the second pic are half and half; The rough blocks are those that were not separated from their arms, hopefully because they were not as trashed. Note one still has the 17426-48 'rocker arm socket', which seems to be obsolete by '51. Perhaps the intake drool hole appeared about the same time as the 18100/181002-49 intake oilers and copper washers. (Or perhaps when the rocker arm socket disappeared?)

The MOCO was still pretty good about literature back then (By the Sixties, not so much....), but we have no clues?

....Cotten

[T. Cotten]

So I finally figured out, Folks,..

The 0259 washer was a lock washer (before nyloks), and the copper seal was 18110-49, with the '41-'54 Parts Book exploded drawing mislabeled by swapping numbers with the oiler, as William noted, Thanks!

It lists the 'seal' for use from '49 to '54.
Have any of you encountered them?
The '58-'69 book lists no seal. Does anyone have a Parts Book from '55 to '57 that might give a clue when they were eliminated?

Why would you cut a gallery to a stud bore and then seal it?

Palmer's (1st Edition) enumerates the various top blocks, but then notes "This is year related but for which years is unclear and it seem to matter not if the bearings are mixed."

Palmer's description of where the various four types of block are used is most enlightening, but makes no mention of the seal, and only mentions that some have the drool holes, and some do not.
Did I miss text elsewhere?

Thanks in advance for any further info, as always,... but at least now I can sort out sets!

....Cotten
PS: Palmer's lists four kinds of blocks: No angled gallery (presumably exhausts?), a gallery uphill for the front intake, a gallery uphill for the rear intake, and dual galleries, apparently for either, perhaps.
So what's this block on the right with the gallery at the wrong end? The FE stamp doesn't look like a farmer's stamp. (Palmer's #3 example on the left.)

PPS: The rough-cast intake blocks have single galleries about .048" wide. The smooth blocks' dual galleries (shown in post #7) are ~.104" wide. Now none of it makes sense.

[Steve Galli]

Went with Eastern Motorcycle rocker arms for my 58 FL Cotten....

[T. Cotten]

Went with Eastern Motorcycle rocker arms for my 58 FL Cotten....

Wow! TWO sources for rockerarms!

Thanks Steve! Got many miles on them?

I dealt with Eastern for decades (but left motorwork decades ago). Those lack the copper-dip treatment, but seventy years later, its probable that better processes have evolved.
Ironically, many reproduction parts produced by lost arts are not produced domestically...
But I don't care if they were made on the Far Side of the Moon, as long as they are quality.

Either way, it should make somebody want my blocks!

....Cotten
PS: I notice you have 'smoothcast' exhaust blocks as well as intakes, whereas nearly every smooth block I found was a Palmer's #4 intake, mated with a Palmer's #1 'rough-cast' exhaust; I must dig out my '65s for more clues...