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MG Midget and Sprite Technical - valve stem seals

If any one has a suggestion as to the best oil seal brand and option, I am determined to stem the oil that seems to be consumed at the valve level. Since rebuild (5,000 miles ago), oil consumption has been excessive with blue smoke when decelerating. Since the head is off for more head gasket experimentation, I would like to have proper seals put on all 8 valve stems. Recommendations as to brand, type and any necessary guide modifications would be appreciated.

I searched the archives and found some material but not what I had recalled seeing last year.
Glenn Mallory

There seems to be a volkswagon type of seal of high quality wich could fit.

But how is your breather set up? I'm assuming a-series here, and it should be lower pressure than ambient.
Alex G Matla

As I asked on the other thread, did the same "machinist" that machined the block face and head do the bore and guide sizing and finish? That kind of smoking is the classic sign of bad ring sealing, and you have an additional problem of a head gasket that can't keep oil where it is supposed to be - it could be going straight into # 1 from the oil passage. While everybody has their own ideas on guide seals, there were a few million engines built that did not smoke with the OE deal.

FRM
Fletcher R Millmore

I think the gold standard in brand name is ...viltron, vilten, voltin, something along that line someone can correct me.

Its a top hat with a little spring around the top, and a hard plastic bottom ring.
Prop

got it !!

"Viton" is the brand name people go into orgasmic pleasure over


Prop
Prop

Don't forget what Fletcher says....

If we think we have the exception that proves the rule...stubborn b*****d....we fit the brown mpi seals on the inlets and standard black seals on the exhausts.Make sure they are the brown ones, we have heard of a couple of occasions when people were supplied with black ones as mpi! As so many people seem overly concerned with a small amount of useage down the ex guides under static conditions, followed by a puff of smake on start up we are now fitting stem seals in and ex and hoping most are ok and dont nip ex valves under hard use. If the oil seals on the ex valves are subsequently removed then the nipping stops but the puff on start up resumes.
Personally, I feel that people are a little too concerned with making old engines the same as modern engines and do two million miles per quart of oil!
These engines are old and will use some oil from the inherent design, they may well drip oil too, that is also inherent design. Why not accept the way the engines were made and enjoy driving them? How would folk cope with total loss engines?

Peter
peter burgess

here here Peter Burgess. I empty my garage drip tray every few months and love the fact that my engine has protected the under side of my car for so many years. So much engineering work for the sake of 5 quids worth of oil every now and then. When I was young every time my Dad filled up with petrol he popped the bonnet and checked the oil and water. That's one of the little things I like about owning one of these cars. I have a Citroen Xsara Picasa as wel, I am not too sure where the bonnet catch is on it. If I wanted a maintenance free clean as a whistle car that handles straight out of the box and fast I would have bought a Fiesta 1.1L. Right, back to my B*ST*RD thrust washer and mains.
N Sayle

okay but....
the a-series engine can be that good so why not make it so

in mini's they can be made leak proof so we only have the scroll seal to worry about.
and with a linebore during rebuild that is mostly sorted anny way.

and with the proper (indeed mpi) seals you do not have to have pufs of smoke and if the head is properly build i am sure Peter will have to agree valve sticking should not be an issue.

sure the service intervals are smaler and you don't get the lifspan of a old merc diesel.

but a freshly built engine can be that good.
And slightly considering the environment while enjoying classics is not bad either (all smal bits help)

that is not saying that you can or should not have just as much fun with a leaking puffing engine

just that when you get it sorted do it right
Onno Könemann

Hello all, unfortunally my engine is back at the machine shop again.My question is are the valve stem seals supplied with the Payen headgasket set BK450 (in the little plastic bag are 8 seals) anny good? Or is it best to order the seals mentioned above?
Thank you in advance.
Pascal
pjw Seezink

Go to minispares and order the brown mpi viton seals
I've had differing quality with the sets
Onno Könemann

To be honest we have now seen the mpi ones after a couple of years hard use and the black ones from Payen seem to remain more supple.Maybe this is a new Urban Myth? Remember the factory did not fit ex valve stem seals. You would be doing this as an extra.

We get to see about 250 heads a year whether being stripped for work, stripped to be reconditioned if we have done them before and maybe stripped to see what sort of problem an unknown head to us may have. So we have built up a reasonable picture after 25 years.

Also remember most guides will need a little oil not to allow stem to guide siezure. As I said above I cannot see why people want to stop all oil going down guides?

Only way to stop any oil being used is to run engine with no oil :)

Peter
P Burgess

Peter,
Whilst I fully agree that these engines were produced in their thousands over many years without exhaust stem seals, it seems to me that many, or most, are now adapted to unleaded fuel. I understood that when unleaded fuel valve stems are fitted they are machined to a greater tolerance and are this is likely to result in more oil seepage. I also suspect that some cam shafts are worse than others in causing oil to be drawn down the exhaust guides.

Whether this is acceptable to the driver is purely subjective. I have no worries at all about a puff of blue smoke when pulling away after idling for a bit. But it does get a bit embarrassing when the amount of smoke results in sitting in a dense blue smog at the traffic lights with pedestrians all around thinking I am second only to BP in the world ranking of oil pollution demons.
Guy

Since we are talking about valve seals and while Peter is on the airwaves, so to speak, a friend has a smoke problem with his standard 1275 engine. This is what he wrote to me:
"midget is still causing concern with the clouds of oil smoke just after the thermostat opens. Only for a couple of miles, then it calms down and all is well. I have no idea what's causing it (still) - nor has anyone else that I ask."
It doesn't smoke on start up, but pours smoke as it warms up - and it is a lot of smoke. Once warm it is fine. Any ideas?
Mike
Mike Howlett

Hi Guy

Usually oil down ex gudes only burns when engine switched off then hot restarted. If idle a little then put foot down or on over run usually inlet guides. A series can be little sods for filling rocker cover with oil if rockershaft etc knackered.

Hi Mike

Is it oil smoke or has he got white vapour from a water problem? Or oil is puddling when left to stand and takes until engine warms up to get rid of it all? Best take head off and have a look. See if oil in inlet manifold?

Peter
P Burgess

Peter,
Good point about leaky rocker shaft bushes. I have had that problem too!

Guy
Guy

This thread was discussed between 25/03/2010 and 22/03/2011

MG Midget and Sprite Technical index

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