Anyone know what this is? also valvetrain question

[adam73bgt]

Hi everyone, was setting some valve clearances today on my MGB and I found this little screw thing just sat on top of the head, almost hidden round the back of one of the rocker arm caps







No i had a good look about and I couldnt see anything missing, the only hole was in the aforementioned rocker arm cap and I'm pretty sure that looked too big (not sure why i didnt try actually screwing it in, think i was scared of dropping it straight through..)





I had a look at an MGB valvetrain schematic and it looks as though it could be a "pedestal locating peg" according to item 36 on this page www.moss-europe.co.uk/Shop/ViewProducts.aspx?PlateIndexID=181#35

I'm not sure if i should trying screwing it in and see what happens? the engine has run pretty fine up till now and i don't know how long this peg has been rattling around the rockers for but it doesnt seem to have done any damage? any ideas anyone?


Also I seem to have one odd rocker out one seems to be a slightly different design to the rest..





Is this likely to be a design feature or probable bodge? It doesnt seem to be causing any harm in any case, just wondered if anyone has encountered this before

thanks in advance for any replies

[colnerov]

Hi, that is what you think it is, number 36, the plate number 37 that stops it coming out is missing.
It is screwed in to stop the rocker shaft from turning, and the oil delivery holes in the shaft from becoming mis-aligned within the rockers. The holes should point down so they deliver oil to the thrust side of the rockers.

Colin

[adam73bgt]

Ah damn, so I'd really have to take the whole rocker shaft off to fix it properly? in order to make sure its aligned correctly?

[colnerov]

Hi, maybe not, just try screwing it back in, the shaft may not have moved. If it has then undo the pedestal nuts to ease the load on the shaft and then rotate the shaft until it aligns again. You can use a bit of mig wire as locking wire as a temporary fix to stop it coming undone again. Then readjust tappets.

Colin