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MG Midget and Sprite Technical - Valve stem oil seals

My Sprite ('65' mk111) has the 1098 10CC engine. I am 'reliably' informed that not all 'A' series engines had valve stem oil seals.
I believe that mine should have - could anyone please confirm this for me. Thanks, John.
J M Hutton

They didn't all have the same seals.
Small bore engines had a small o-ring around the valve stem, rather than the later seal which fits over the valve guide.
No reason why you can't fit the later seal.
Dave O'Neill 2

Thanks David. I assume from that, all 'A' series had seals then - but older versions just an o-ring seal. I will go for the later type then. Advice appreciated, John.
J M Hutton

I think if you fit the later type seals you need to remove the sheet metal tophat piece that goes under the spring retainer as otherwise IIRC it'll hit the seal.
David Billington

Hi David(B). So would it be advisable to revert to the o-ring type then?
J M Hutton

I'm not sure which piece David is referring to.

AFAIK there are no issues fitting the later seals, except the valve guide *may* not have a groove to retain the seal.

Dave O'Neill 2

Thanks Dave(O'N). Most unfortunately, engine is back out of car, and head and block back at the engineers, so don't know if valves have a groove or not. It was all going so well......
J M Hutton

To clear things up I think that part wasn't fitted to the double valve spring engines fitted to the spridgets but to the lesser single valve spring O ring oil seal cars of an older vintage. Here http://www.somerfordmini.co.uk/eshop/index.php?main_page=page&id=115 it is listed as shroud 2A545 , also http://www.somerfordmini.co.uk/eshop/index.php?main_page=page&id=116 . Looking at the valve pics at the bottom of the illustration it looks like the later O ring valve seal cars didn't have the shroud and then after that the lip seal type was fitted. Shame it doesn't seem possible to zoom in on the illustration although it is and Adobe flash thing. Some discussion here http://www.mmoc.org.uk/Messageboard/viewtopic.php?f=4&t=61814 .
David Billington

Well you learn something new everyday!

I had never come across those, even with my A35 - probably because I never did anything with the original head, only a 12G295 followed by a 12G940.

Pic courtesy of Moss Europe...

Dave O'Neill 2

Thanks David(B) - and my engine definitely has double valve springs. Will have another read of all this. Many thanks, John.
J M Hutton

It's always mystified me how the earlier O ring oil seal works. The only thing I can think of is that it prevents oil collected in the valve collets from dribbling down the valve stem. It can't do anything about the general oil mist in the rocker box getting onto the stems below the seal.

The later ones really need grooves in the top of the guide to work properly.

Rob
MG Moneypit

Thanks for that Rob. I had oil sitting on top of the pistons after a run - oh, and used a litre of oil over a 74 mile run, plus blue smoke out the exhaust....... this on a completely rebuilt engine, that I was told would improve with use! John.
J M Hutton

This thread was discussed between 07/02/2017 and 11/02/2017

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