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MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Rockers

Prompted by Tim's "Noisy Engine" thread on the general page. My 1275 is very tappet noisy so I was thinking of refurbishing the rocker assembly. This new territory for me as I have only ever set the valve clearances with the knowledge gained in the late 70s. The question is where to start. Can I dismantle the whole assembly and strip it on the bench and what should I replace. I'm confused by Moss and MGOC catalogues that have options on rockers, Sintered, Pressed and Forged, what is the difference?
Pete Ottewell

Id use mini spares website instead of moss for this...in fact you can probably purchase a fully refurbished assembly thur them cheaper than you can do yours

Better yet, spring for a 1.5 :1 ratio roller tipped rocker kit ...it eill be the same as installing a high performance camshaft... Only easyer and cheaper
Prop and the Blackhole Midget

For once Prop is right ;)

Minispares is the place to go for most A-series engine parts.

First step is to remove the complete assembly (this will release the clamping on the HG so this should be replaced)

-Unscrew the locating screw in the middle post
-Remove the split pin one one side
-remove all the rockers and posts

Now you have a clean rocker shaft.
Inspect it for wear if this can not be seen inspect for ridges with your nail.

Now take a rocker and slide it around the post and at a place where usually no rocker is situated (an UNworn piece)check for play.

Then one by one visually inspect the rockers pads.
look for indentations of the valve stem on it.
It should off course be a nice smooth surface.

By now you have determined what is worn and what not.
Replace (or fix) what is needed or if you want upgrade.
Onno K

<<Now take a rocker and slide it around the post>>

For 'post' read rocker shaft.

Forged rockers were fitted to early 1275s and were the same as Mini Cooper S.

Pressed rockers were fitted to the vast majority of 1275 Spridgets. Earlier 1098 Spridgets and other small-bore A-series engines were also fitted with pressed rockers, but these are different and not suitable for fiting to 1275 engines.

Sintered rockers were (possibly) fitted to late 1275 midgets and all mid-'70s onwards A and A+ engines.
Dave O'Neill2

ehhh oops!
let's just say the Beer at the ring was good this weekend ;)
Onno K

Also if you need a new shaft, get the heavy duty version from mini spares, it's a few quid more but is supposed to be stiffer and last longer,
Graham.
Graham P

This thread was discussed between 12/08/2012 and 17/08/2012

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.