engine and drivetrain Old style Viton valve seals vs. newer "teflon" sty

[Guest Anonymous]

In another post, Mr. Mike made the following suggestion regarding valve seal preferences.

"consider replacing the valve guides with those used on the later M10 engines in the E30 cars. These guides use a newer design stem seal that is much more long-lived than the earlier style used in the 02 engine.

At least that's what I've been told by several well-known engine rebuilders."

I have often assumed that newer also meant "improved" when it came to valve seals and asked my machine shop to install the newer valve guides and seals in my early 530 head. The shop advised against it .

They claimed they did as asked by a customer and the customer was disappointed with long term results (whatever that means). They also said that doing work for several "high end" shops and a small dealership, all of them specified use original style seals and guides. They ultimately sold me on the old style and I have little about which to complain. Now, I have the head off of my 02 and am reconsidering the issue for that head.

Aside from the fact that the old style seals are often supplied with a head gasket set, do any of you still use the old style seals when given the choice?

If so, why? Are there really any advantages to the old style assuming you are going to replace the guides anyway??

TIA

[bevans6]

I confess that I don't have back-to-back testing results to show you, but I use the newer style seals. They need the valve guides machined down to fit, or use later style valve guides when doing a complete head job, and they are required when fitting any dual valve spring, which makes them mandatory when fitting many performance cams.

I have them because I am running a 316 cam in a race engine with dual valve springs.

Brian

[TobyB]

The new 'old' style seals work better than the ones that BMW used 40 years ago-

better materials!

I've used both, and frankly, have had problems with neither

when they were under 10 years old.

But that's me.

t

[Guest Anonymous]

I am not trying to argue with any of the previous posters. I don't take a position since I have used both style seals. BUT, I am wondering if BMW takes an official position regarding valve seals new/old vs new not-so-old. Viton v. teflon

For example, BMW has evidently taken an amended position regarding head gasket torquing. And, as far as I can tell, newer gaskets carried by BMW have the "beading" around the perimeter of the gasket for presumably improved sealing. I suppose another analogy might be made with starters now offered for the M10.

I am not expecting anything, but perhaps there has been a service bulletin regarding this subject.

Incidentally, inasmuch as Viton is still being offered, perhaps it is still a viable alternative. CD ISOLD IT! seems to think so: http://www.bmw2002faq.com/component/option,com_forum/Itemid,50/page,viewtopic/t,296272/

Thanks

[Anthony]

I confess that I don't have back-to-back testing results to show you, but I use the newer style seals. They need the valve guides machined down to fit, or use later style valve guides when doing a complete head job, and they are required when fitting any dual valve spring, which makes them mandatory when fitting many performance cams.

I have them because I am running a 316 cam in a race engine with dual valve springs.

Brian

My local machine shop cuts them down and uses a ford seal (4litre I think) and on my race heads it seems towork great for a dual spring set-up.