Exhaust Stem Seals
Turbo Mini Forums

I know that stem seals are not "needed" on the exhaust side of a Turbo (8mm stems), but my mechanic installed them anyway. They're the Viton ones.

Is there anything wrong with having them? It's my understanding that having some oil slip down the stems might be a good thing, and I don't want to seize them because of capping them off with seals...

What is the general thinking on this?

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1967 Cooper 's' Turbo build @ www.drjing.com

the generall thinking of this is.... to do without them ................

but.... i have run engines A series with these fitted without any problems, what so ever!

if you look at other engines

you will find that most of them fit the seals on the exaust side!

i would remove these on the exaust side for the reasons you state


ben:

Thanks, Ben. I'm a little bummed, because I had asked the machinist to install the seals on the intakes on both heads, not all on one. The viton type are not cheap!!! I'll have to buy some more, as they can't be re-used for the intake...

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1967 Cooper 's' Turbo build @ www.drjing.com

after working with heads for some years, generally seals on ex valves increase guide wear

On performance engines(heads) I build I only fit seals on the intakes. On road heads, I fit them on all eight.

I also had a lot more wear on the exhaust valves and guides with seals fitted.

Bimmer Twinky headed and turboed A-Series:
http://www.minifreunde.at/harry/projects.htm

Generally with the increased heat of the exhaust valve stems, the stem seals quickly go 'hard' around the stem and so don't do much sealing any more. Not sure how these Viton ones you have got will fare.
But correct really in what you say, that they are not needed.
Why not just remove them yourself from the cyl head? Easy enough job with a valve spring compressor and an hour.......

Thanks, guys! Will definitely remove them. I'm just sad that they are most likely now too deformed to do me any good on the intake on the other head...

Tom, an HOUR?!?! Good night, man! Are you doing this in the dark, with one hand?

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1967 Cooper 's' Turbo build @ www.drjing.com

Well seeing as you got your machinst to build the head for you, I assumed you didn't have the kit to do it yourself, hence the hour........

Usually takes me an hour as when doing the last valve of the 4, I release the spring and it shoots the collets all over the bloody garage, I then spend 45mins looking for them.

LOL So, 10 minutes doing the valves, 50 searching for the collets!

I had the machinist assemble the head because they are doing a valve job, and this ensures that each valve that is lapped to its seat stays with that seat. I borrowed a spring compressor from a co-worker to remove the springs after the fact. I'm going to have to get one for myself, though. Having the proper tool makes a WORLD of difference! Beats using a hammer and socket.

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1967 Cooper 's' Turbo build @ www.drjing.com

On 20/07/2005 04:59:03 Dr. jinG said:

LOL So, 10 minutes doing the valves, 50 searching for the collets!

AlexF

I think eveyone that has done a head has done that more than once. However hard you try to keep them under control one manages to escape LOL evem if it only slips out of you fingers when your trying to put them back in!!!

Very true, Mike. I did this the other day. Got all the exhaust seals off. I set them aside, in a bag, hoping that since they haven't been on the head long (and not running at all) they might spring back to seal a standard valve. It will be a couple of weeks before I have the other head coated, so maybe there is hope...

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1967 Cooper 's' Turbo build @ www.drjing.com