The rocker arm shaft is solid. For that to break-
I am thinking that the head must have been done or==
The mechanic - in trying to stop the tap or knock sound put a shim
under the rocker shaft on one and and not the other - and that snapped it.

A shim on one end and not on the other would stress the shaft.

 

Rocker arm shaft is hollow.

 

Would never give that shop any more business. They do not seem very educated on rover or determined to please there customer.

 

RE: Rocker arm shaft is hollow.

Pix of same

 

I assumed it was solid - except for bolt holes and for oil holes from top to bottom.
That's what I get for assuming. The first three letters of assume.

Mine felt heavy when I was replacing them on the D2. Guess those rocker arms
have some weight..

Still ---- For one to crack in half? Seems there needs to be a bending force on it.
Surprised the shaft is then that brittle.

As I understand it - adding heat to steel in the manufacturing process can make it
tempered and harder but more brittle also?