Rocker shaft problems:


This is a very serious matter and may ruin your engine if left unattended:

Some years back Lex Stibbe from Holland had a broken rockershaft. Right in front of the foremost supportbracket the shaft had sheared off and in the proces it had also knocked off the head of the valvestem, causing the valve to drop with this time luckily not such desatreus effects. The valve did not drop right into the engine for unknown reasons. Lex was very lucky this time.

It made me thinking why the valve and the rocker shaft broke at the same time.

While working on the engine of another VA I wanted to check for top end lubrication so I had the engine running with the rocker cover off. This is not very advisable if you have a very neat environment as it can make quite a mess with oil spettering all over the place.

While observing the rockershaft I noticed that the bit of shaft in front of the foremost supportbracket was actually moving every time the valve was pushed open.It was jumping up and down. Because I did not like this happening I took the whole assembly off the engine and inspected all the bits and pieces carefully on my workbench. I found out that there was actually quite a bit off play where the shaft is going through the supportbracket, causing the jumping up and down of the shaft. I also saw that through this hammering action the shaft had marks we dont want and the supportbracket is worn to the extend that it is no longer serviceble in this condition.


It is these hammering marks that eventually will make your shaft break with possibly horrible results leading to a badly blown up engine.

Looking at other engines in my stock I saw that the front and rear supportbrackets are more like the design of the middle two brackets, being slotted and carrying a ring to fill the slot. On the front and rearbrackets the ring is flat on one side to make way for the shaft. This construction makes it possible to clamp the shaft tight and it no longer hammers into the bracket.

Seeing this I studied the parts list to see if it was one of the many modifications which was made during production.

Yes, from enginenumber 2250 the front and rear rockershaft supportbrackets are different and have a different partnumber, also mentioning the different washer.

I would strongly advise everybody with a VA to check your engine on this point before disaster strucks! Remember that although your VA carries a garuanteeplate I doubt that MGs in there present situation will positively react on your claim.

I do not think that there are enough proper brackets available if every body needs them, but with some tinkering from a good engineeringfirm a "wrong" bracket can be modified into a proper one.


Back to VA Indexpage