A7 Tappet (cam followers) retaining stuff

[Ratchet Richard]

Hi all
A few questions regarding my A7 1958 cylinder block Tappet retainer attachments.
When I removed the cylinder block I found that the Tappet peg (67-0332) was loose. On inspection I found that the ball was missing from below the top ball screw.  I have had a look at undoing the top screw but it looks as though it is damaged from previous attempts.  First, I am right in thinking that once the Tappet peg is in place and the cylinder block back on the casings it cannot come out.  Second, I am not to confident working with cast iron and was wondering if heating the cylinder block by the top screw will be helpful in trying to get the screw out? 
I have acquired an old cylinder block with a mind to refurbish it ready to replace the one on the bike at the moment.  On close inspection I have found that someone must have taken a hammer approach to knocking the Tappet peg out without removing the screw and ball bearing.  The cylinder casing has a small bit missing where the ball would have been.  Is this something anyone else has come across and is it fixable?  Thanks for any replies.

[muskrat]

G'day RR.
That peg is usually a snug fit in the barrel so it must have been in and out a few times. I'm not sure if it's captive once the barrels are on but BSA put the screw and ball there for a reason. If the peg moves and the two middle followers come into contact the un-worn part of the peg it could upset the apple cart.
The screw must be removed. Gentle at first. Penetrating oil o/night followed with heat around the screw. Grind down an impact bit to fit and try that. Next is to drill with a left hand drill and easyout. Still no luck, drill right out and either re-thread next size up for 5/16 unf drill size I = 6.91mm (7mm will do).
I would not reassemble without the ball and screw.
Cheers

[Ratchet Richard]

Thanks for advice Muskrat.  Managed to get the top screw out with a bit of heat lots of plus gas.  I will feel much better when it all goes back together knowing that the peg is safely located. 

[muskrat]

G'day RR.
That's great mate.
Buy a new screw. When replacing it all make sure the followers move freely before you lock up the ball and screw. Yours should be easy with the peg loose in the hole. Mine is tight so it's a get it right or try again. Once happy put a light centre pop on the peg and body so it always goes back the same (not a job done often).
Cheers

[berger]

somebody did a hammer trick on these barrels to get the peg out

[muskrat]

somebody did a hammer trick on these barrels to get the peg out

May have taken the screw out but neglected the ball.
Cheers

[Ratchet Richard]

somebody did a hammer trick on these barrels to get the peg out

Hi Berger, where the barrels fixable? 

[berger]

Ratchet richard i will leave as is if i ever use them , once the peg-- ball--and screw are in they will be ok. ball can't fall out when sat in the peg groove.