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MG MGB Technical - Rocker assembly

Hi all

I decided to give my rocker assembly a clean today and to inspect for any worn/damaged bits etc.

The rocker shaft was straight and true, all oil pathways were clear but there were indentations corresponding to where the pillars and rockers fit.

All the pillars appear to be ok the grub screw that secures the rearmost pillar is good.

The toes of all rockers look good, but the heels of four of them are flattened off slightly. Also, my manual suggests that the bushes in the rocker arms are removable, but mine look as if its integral to the arm itself...

I definitely need some new split pins and springs... but would you suggest four (or maybe a complete set) of new rockers arms? What about the scouring on the shaft? Is there anything else I should look out for?

I've attached some pics.

Thanks as always,
Rick.

R Sims

And here is the rocker arm...

R Sims

Difficult to see any wear on the rocker ball from the photo, but they don't normally suffer much. The shaft does look like it has some wear and would probably be best replaced.

The bushes are a press fit, so you won't be able to just push them out. You can check them for wear by fitting each rocker to an unworn part of the shaft and checking for play.
Dave O'Neill 2

Rick,

the MGOC sells rebuilt rocker assys on an exchange base. I would give it a try, as there is wear to be seen on your pics and this will increase in the future, robbing further power and lower the mpg results too.
The MGOC kit is not expensive and i used some of them with no problems during the last years.

Ralph
Ralph

Check one of the repair manuals on how to replace bushes. I has a shop in Oregon refurbish mine and it has worked fine for many many years. Any good machine shop could do this also especially if you help them with the parts.
Robert McCoy

Although the bushes are supposed to be the wear part, typically the shaft wears first. I'd bet your bushes are probably fine, but the shaft is definitely not. The only correct way to measure the bushing clearance is to use an outside micrometer and a snap gauge, so if you don't have access to these, you'll need to take your bits to a machine shop.

Moss sell hardened rocker shafts, I would imagine MGOC do as well. I would get a hardened rocker shaft, along with the replacement springs and split pins, and reassemble.


Paul K

The problem is that the soft bush material picks up steel particles which then wear the shaft - fitting a new shaft alone will be a short term fix as it will wear quickly.

Rebuilt assemblies have the bushes and posts reamed out 5 thou and an oversize shaft fitted.

Tuftrided shafts come only in standard size so you will have to fit and ream new bushes or exchange them for some already done.
Chris at Octarine Services

This thread was discussed between 16/10/2007 and 30/10/2007

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