rocker shafts

[my8thholden]

I read here over a few years that NEW rocker shafts are hard to get if not impossible , has any one here managed to get or knows of where to get , or have had made a pair of new rocker shafts for Holden grey engine ..thanks Vern

[ardiesse]

Vern,

You would be right, I think.

I've sometimes thought about getting some made, but the effort of reverse-engineering . . .

Otherwise, you could go talk to someone like Diamond Hard Chrome at Enfield, or A1 Metal Spraying.  There's not much difference between a rocker shaft and a hydraulic ram.

Rob

[my8thholden]

Rob ,,What is the correct diameter of the rocker shafts ? , is it in a technical book, my shaft measured 20.1298mm OD where the pedestal is , ie unworn , in the manual only reference I can find is in bush replacement where allowing for clearance it would be as near as .7925 which is near enough to the mm reading ..That is an odd size , one would have thought Holden would have used a standard size of hollow tube ...cheers Vern .

[ardiesse]

Vern,

There'll be reasons why GM-H chose 0.7925", but they're not immediately apparent.

The rocker shafts were in fact stamped out of sheet, rolled up like a hollow section pin, welded and then ground to size.  I guess it saved on material, and there was no need to drill the hole in the shaft.

Rob

[my8thholden]

Rob..They say the day is wasted if you don't learn something , I did not and would never have guessed the rocker shafts were rolled from sheet ..I'll seek yours and anyones comments , you would be aware the shafts wear on the underside where the operating action is the most load ,the thought of turning the shaft over 180 deg ..drill new oil holes on under side , reason being ,move the worn section to the top , its by no means a perfect solution ,but a shaft with minimal wear would be an improvement ,would that create too much back lash ? would you block off the oil holes now on top ?  .keep well Vern .
PS ..Thinking about the oil holes ,the holes now on top would have to be blocked off ,cause they would then be in line with the hole in the rocker ,oil would shoot straight out and the under side would starve for oil.

[DCE80]

Here's a question for you all. What was the change made to the shafts from FJ engine 197344. Looks like there was a front and rear before eng 197344 then it moves to a single part number instead of both front and rear part numbers.
Cheers
Dan

[my8thholden]

Dan ..I will watch the reply to your question as even though its an area I have been working in ,I dont know the correct history , i suspect it co incides with the change from the stepped pedestals to the stronger even ones ..I cant expand your image to see that ..By the way with mine , i did redrill and weld old holes and turn shaft over ,fit new rocker bushes , so far so good ..cheers Vern .

[Harv]

The rocker revisions are noted in Service Bulletins H-82G (pages 2 and 3):
https://www.fxfjholden.com/forums/service_bulletins/H82-G.pdf

, and additional connector changes at H-96G:
https://www.fxfjholden.com/forums/service_bulletins/H96-G.pdf

I got permission from GMH to scan and upload all the humpy service bulletins to the FX/FJ forum - the full set are located over here:
https://www.fxfjholden.com/forums/viewtopic.php?f=50&t=5359

(... you wonder what I do in my spare time  ).

Cheers,
Harv

[DCE80]

Thanks Harv!!
Your info has helped me many a time! Love your work!!
That was some interesting reading. It would appear the earlier shafts had larger ID of shaft bore as there was no seals on the oil connector between the two shafts. The mentioned overflow pipe is new to me. Haven't seen one of those in the few engines I have worked on or seen.