Stem Oil seals lifting off of valve guides
Turbo Mini Forums

After Mini in the park the car was smoking like an old victorian harth so I changed the stem oil seals, no change, so I changed the turbo, still no change. so out came the engine hoist.

Before I started down the course of an engine change I decided to check the stem oil seals, to my surprise 3 of the 4 exhaust seals had lifted off of the valve guides. How shamefull to think I could have made such an error....but did I?

I took the old bucket for a run down the M1 and all seemed fine until after a few days, on the over run after a few minutes at high speeds she started pouring smoke out the back end and I do mean a lot! It turned out to be the stem oil seals again the little buggers keep lifting off of the valve guides.

I have only ever fitted the stem seals from the turbo head sets 8 in total and have never come across this before. Are there alternative better seated and better sealing valve stem seals available? or are they much of a muchness.

Own the day

the exhaust valves dont really need stem seals they normally lift of coz the valves are thicker. ive had a few turbo heads without any stem seals on the exhaust valves sounds like worn valve guides to me matey.

no longer a series, but still 1.3 turbo.

dont normally put them on the exhaust valves.

new guides needed

saves taking the lump out!

doh, beaten to it, but same response!

Own the day

Just because they are in the kit/fitted, doesnt mean they actually do the business.

They may help a bit but if you are getting a fair bit of smoke then its the guides.

The seals are there to help, as already said. With no seals you should not expect much smoke, certinely not plumes. Sort the guides before re-engineering something that doesn't need re-engineering.

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Robert had a similar problem, half way down this page:



If the guide clearance is high, it will push the seal off and cause it to smoke.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

there were some modern type sprung plastic seals on ebay for minis a while ago ,they may have a more positive fixing mr joshua ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

I am taking in all that all of you are saying. This was no gradual event. I have been happily driving with this engine then suddenly poof plumes of smoke when I close the throttle. Change the seals get a few hours of good motoring then poof there it goes again I have been loaned a box of stem seals of various designs and have found a few with smaller centre holes and have fitted these to the inlet valves so far so good.

What I have noticed is that the seals do not seem slide far enough down the guide to allow for the rib on the inside to lock into the undercut in the stem, some positions are worse than others.
Also when fitting the springs I can feel the inner spring catching on the edge of the seal as I drop it into place.

The last time I did stem seals was back in 2003 and I never had any issues but since useing the seals recently purchased nothing but trouble.

Own the day

The clue for the inlet valves are the Viton type seals. I have a few here, and I believe KC are also selling them. These will need to be hammered down onto the guide, so fit very snugly.

yep KC sells them, as do MRA minis, definatly look much better, like modern std fitment stuff.

website:- http://www.terryhunt.co.uk

I think the fact that a lot of people dont run them and dont have issues has to say that guide fit plays a massive part.

It may well be that the seals are masking the overall problem and will help you but for the sake of 4 new guides, its probably easier than continually messing with seals...

Hi,
If the guides are worn the pressure in the port will be coming up the guide and blowing the seals off, that's why they did work but don't now
Cheers,
Gavin :)

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