308 - Upgraded Valve Stem Seals? Other makes?

Hello all,

I have been told by someone who builds these engines that the normal Ferrari valve stem seals are not very good, they crack easily on fitting and having seen them they do appear to be a very old design, made from hard teflon coated white nylon with an outer locking collar.

Does anyone here have any experience of using a more modern design seal? I believe some of the racers used Mk2 Golf Gti seals which are supposedly better.

Thanks!

 

Well, I hadn't heard that about the valve seals being "not very good." If true, maybe my 328 got a 'lucky set'; it shows no sign of the typical smoke caused by bad valve seals.

Regardless, cracking upon installation sounds more like poor installation than poor valve seals...

 

Same junk seals the Germans used for years. Anyone with a brain has been using Viton seals for a very long time.

 

Because your guides are pretty good and unlike most pushrod engines especially the 4 valves are well shrouded from an oil bath.

Not unusual to see a number of broken seals during teardown. Easily installed without damage but break in use. I have seen many pieces drop out during oil changes. The Europeans loved them for some unknown reason. Have not been used since mid 90's.

 

Number 27, is that you, is it the valves not sealing then rather than the piston rings?
kc

 

To change to a viton seal on 2v engines, last I checked, you had to change the guides as well. Bill at GT has guides and Elring viton seals that fit just right. The white OE teflon seal is horrid to get on the stock valve guides just right.

 

I have ordered them from Amazon. 2v and 4v both. Fit stock guides like a dream.

Teflon goes on easy if you throw them in a coffee cup of hot water for a while. Still junk.

 

One of the seals I use does have a VW application. I think the other was for some POS 4 cyl Mopar or maybe a Mitsubishi.

 

I''ve installed PC (Perfect Circle) Teflon seals on a TON of US v8 engines. They are excellent valve seals and we never had any issue with them so I'm surprised to hear them called "crap seals" in this application. They do require very tight guide/valve stem clearances or they will go egg-shaped and lose their sealing ability but properly machined guides/valve stem clearance are just part of the engine building process. Maybe the Euro teflon seals were not as well made/designed as the PC seals?

OR...Ferrari's valve guides were...uh...less than optimum?

 

Never seen a PC teflon seal and maybe its better made but have never once seen it as a better option than a viton seal. Of all the OE applications I am aware of all had a reputation of needing guide seals and sometimes guides prematurely. Regular eyes on failure of teflon seals in many makes (Mercedes, BMW, Ferrari off the top of my head) has hardly convinced me of of any need to pursue a higher quality version of what I had seen fail so many times. Especially when such a good option was so easily sourced. I hate to experiment, I like using what I know works and viton seals work. Been doing this for a while and yours is the very 1st time I have heard a positive opinion on teflon seals.

 

I totally agree with relying on what's known to work! Maybe the general higher RPM of European engines has something to do with the valve seal suitability. In any case, if I needed new ones for my 328, I would be installing the seals you recommend due to your experience with these specific engines!

 

I was on a garage tour of a Ferrari dealership once. They were talking about how they were familiar with the various models and the things to expect to go wrong. When they got to the 328 the service manage paused and said, "The 328...well they never come in."
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You know, I hate threads like this. Just another "all Ferrari parts are trash" thread. Here is a picture of valve seals that came off my 308 QV in 2010 when they were 25 yrs, 27,000 miles old. None are cracked or broken. There was no oil seepage. They came off when I hard to replace a couple of valves. Just dug them out of my parts box and took the photo today for this thread because I wanted to see if they were cracked. What's more, I also made a video showing that the now 37 yr old seals are still very flexible.

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https://www.youtube.com/shorts/w-cNsaf3LiI

 

That's not the intention of this thread at all. These seals are a very old design, perfectly fine in their time but not great by today's standards. The American V8s had them as well when first released but upgraded modern types are now used when they are rebuilt. With respect, saying your seals are fine after 27K miles hardly proves they are a good design, valve moment in the guides is what tends to put them under stress and you won't have that with such a low mileage. I believe part of the problem is that they are tricky to install correctly compared to the modern ones.

The reason I asked in the first place is that I have had issues with mine on a newly rebuilt engine (the seals were installed by a proper shop, not me) and am keen to make sure I use the best possible option now it that it has had to come apart again. I do NOT want to have to do this all over again!

Thank you all for your replies which were useful and much appreciated. Some of the guys who race 308s here in the UK have used Golf Mk2 seals, which are apparently pretty good. I have got hold of one and will be investigating tomorrow.

 

Don't blame him. He's the smartest man in the room and needs to prove people wrong to feel superior.

You see how he does it. I am referring to exposure to thousands of these cars against his singular experience. He's right, I'm wrong. Its simple when you are the smartest man in the room.

 

I've lost track - who is it we are slagging off here?

 

Me. Don't worry about it. My comment was directed at him but rather the seeming Ferrari Chat mantra that if a part on one car does fails, they all will sooner or later.

 

Jack's heads were only just rebuilt, so if the seals are leaking it seems like something was not done correctly. Not sure it has much to do with the 'quality' of any Ferrari specified part. However, I can understand him wanting to get it right this time around (although I reckon 27K miles would probably take him about 10 years to do, even if he uses the car quite a lot).

 

I am in the original seals (2v engine) are junk camp, they were fine in the 70's but better materials/designs are available today. My experience is that they tend to become brittle and crack or become so stiff that they no longer seal. Many years ago there were some threads on replacement seals (Viton) from either a BMW or Audi/VW that worked well.

 

FWIW, I did some 'research' on this subject by calling four different engine builders that I used to work with to see what they do nowadays re valve seals. One of them stated that Teflon seals are the ones he trusts/uses; the other three use Viton. All of these companies are well-known professional builders of high performance/competition engines.

Hmmm... if I was a marketing person, I could use this extensive data to state:

"Viton valve seals are preferred by the majority of modern engine builders!"
or
"Top engine builder says, 'We trust only Teflon valve seals for our engines!"

 

Try a different one to the “ new “ ones fitted recently that leak .
Change tack .
The offending heads off , the hard works been done .
This is turning into a oil thread .

 

Agree -- this work was recently done, so not enough time to fail in a typical age/wear fashion. That leaves possible issues due to part quality or installation. After seeing Jack's recent video, I think there is more to be learned here and I am curious to see how things unfold.

BTW, I am a big fan of Viton seals (they should be far superior to anything teflon/nylon based) but they can have problems too. I have used Viton seals in more translating and rotating shaft applications than I can remember. Just like any seal they need careful inspection and installation. They are fairly robust when it comes to dealing with play/movement, but any sort of damage, interference, or contamination can lead to a failure eventually.

 

For those not in the know about Jack and his 308 GTS (can't be many on here, surely? ), look up: "Number 27 influenzo" on Youtube

 

Never watched his channel before but he has a video form June 2021 where he notes smoke on start up just after the rebuild. Recent video show all exhaust ports covered with oil. Perhaps the wrong size seals were installed. Seems unlikely that all the seals would fail or were damaged on installation, but you never know.

 

Am I the only one who initially, and continually, clicks on this thread thinking it's about TIRE valve stem seals?