I've searched and searched for VITON valve seals... | FerrariChat
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I've searched and searched for VITON valve seals...

Discussion in '308/328' started by ProvaMo, Jan 8, 2012.

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  1. ProvaMo

    ProvaMo Formula Junior

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    #1 ProvaMo, Jan 8, 2012
    Last edited by a moderator: Sep 7, 2017
    Could use your help: I have tried to find the BMW valve seals which are supposed work on the F-cars, in my case a 1979 308 GTS Carb US 2V. I've tried multiple thread and internet searches and can't find the fitment. There appeared to be significant discussion on this being one of of the culprits of higher oil consumption in the 308.

    Sounds like Newman (circa ~2002) had found some green seals from an early BMW M5 (possibly in Viton) that worked well, but the only BMW part number I could find in the F-chat search was for a 7mm stem (versus my 8mm stem, with a 10-11mm guide O.D.). UK Superformance shows a "rubber" seal available, but they do not indicate if it's Viton.

    I currently have the heads apart and would rather not go with the expensive (and what appears to be hard and brittle) white teflon seals. Anybody out there have recommendations or guidance on this...? Thanks in advance for your inputs!
    Paul
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  2. Speedmade

    Speedmade Formula Junior
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    Reed H
    #2 Speedmade, Jan 8, 2012
  3. thecarreaper

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    #3 thecarreaper, Jan 8, 2012
  4. Ferraripilot

    Ferraripilot F1 World Champ
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    #4 Ferraripilot, Jan 8, 2012
    There's another that can be used which is the same thing. I'm going to try and find it a little later.
     
  5. ProvaMo

    ProvaMo Formula Junior

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    #5 ProvaMo, Jan 8, 2012
    Thanks for the inputs, Ferraripilot: thanks in advance for for your adder.

    If anyone has experience of which valve seals they've had the best results from, looking forward to hearing about them.
     
  6. ProvaMo

    ProvaMo Formula Junior

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    #6 ProvaMo, Jan 9, 2012
    A special thanks to Speedmade on two counts:

    1- I took some measurements, looks like the No Limit Motorsport valve stem seal in Viton, p/n VS-VW8-E will work, just what I was looking for, good price.

    2- I ordered Cometic Head Gaskets from the same guys; their prices appear to be extremely competitive, though it’s just an order at this point…
     
  7. 3px19

    3px19 Karting

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    Calvin crouch
    #7 3px19, Jan 9, 2012
    Do you also recommend their polyacyrlic intake valve seals or do you recommend something else (material, brand, etc)

    thanks for grat info
    Cal
     
  8. MNExotics

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    #8 MNExotics, Jan 9, 2012
    Paul
    Let me know if we can flow bench your heads with the carbs attached. I am curious of total system flow.
     
  9. MiuraP400

    MiuraP400 Formula Junior

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    #9 MiuraP400, Jan 9, 2012
    Viton or teflon, both work well. I would not recommend anything else. Just be careful when you install the valve spring retainers, it is easy to over compress the springs and damage the seals. I suspect that is what led to the failure of your current seal.

    Cheers Jim
     
  10. ProvaMo

    ProvaMo Formula Junior

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    #10 ProvaMo, Jan 9, 2012
    Cal- I am going with Viton for both intake and exhaust. There's various data out there, but in general I found the poly acrylic is good to 350 deg F, and the Viton to 450 deg F (more comparable to PTFE). The price difference was minimal at ~$.22 more per seal for Viton. The factory used the white PTFE/Teflon for both intake and exhaust.

    Ben- That would be fun and informative to flow the heads to compare the injected 2V. I assume without the valves? I could be ready in about a week. Then you'll talk me into the port & polish offer…

    Jim- Thank you for the guidance: knowing me, I could have “compressed-away” to easily get the retainers back in there. I will take some measurements, with margin, to understand the limits. No failures, I’m replacing the old seals to freshen up the heads while I’m in there (removing carbon galore).
     
  11. MNExotics

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    #11 MNExotics, Jan 10, 2012
    I am interested in flowing them as they would be on the assembled engine with valves and carbs. I would also like to flag flow the ports to show dead spots.
     
  12. MiuraP400

    MiuraP400 Formula Junior

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    #12 MiuraP400, Jan 10, 2012
    I like to include the air cleaner too when I flow a head. Sometimes there is some losses there. What do you mean flag flow the ports?

    Cheers Jim
     
  13. MNExotics

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    #13 MNExotics, Jan 10, 2012
    Flag flowing is basically a small streamer that you move around the port. This allows you see where port velocity is high and where it is low. You can also pick up a sense of how the air flows around the valve stem and protruding guide. The Hemi heads on the 2 valve engines and in general are not very good at air fuel homoligation and that's part of why they foul plugs so easily. In flag flowing I am hoping to understand where and how I can induce swirl to improve that homolgation.
     
  14. MiuraP400

    MiuraP400 Formula Junior

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    #14 MiuraP400, Jan 10, 2012
    I see, I do that with a bit of thread.

    Are you trying to induce swirl in the cylinder or in the port? It sounds like you are trying to do it in the port. If you are trying in the port, note the flow is turbulent, so all the laminar flow tricks will not work.

    Cheers Jim
     
  15. MNExotics

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    #15 MNExotics, Jan 10, 2012
    String works but the advantage I have seen with a streamer is you can see it twist. Ideally swirl would be in the cylinder but Hemi combustion chambers make it difficult to induce swirl. Hemi combustion chambers are great at full throttle but are marginal at driving around town. The ports on the 2V heads ar very smooth and don't think there is much for dead or slow area but I also suspect they push the fuel to the top of the wall at the bend. I think that a shallow scallop after the radius could help get the fuel off the wall and help homoligation. Of course the goal is to not lower the flow number. Until I get on a bench and test molded inserts, I am guessing.
     

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