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Camshaft seal help - 1985 QV

Discussion in '308/328' started by Banzairacer, Dec 27, 2019.

  1. Banzairacer

    Banzairacer Karting

    Aug 24, 2017
    233
    San Diego, CA
    Full Name:
    Sanjeev Thohan
    I need some help with a diagnostic issue for a camshaft seal leak.
    I've had the camshaft seals replaced and the one near the passenger side nearest the firewall continues to leak on the belt side despite new parts. The other 3 are fine??.
    Shop took it apart and replaced the seal again (yes a chore) - still leaks??

    is this a potential bearing issue?
    does the camshaft need balancing? and if so can it be done?
    what else can it be?
     
  2. yelcab

    yelcab F1 Veteran
    Consultant

    Nov 29, 2001
    9,906
    San Carlos, CA
    Full Name:
    Mitchell Le
    That is a ***** isn't it? I suggest using a thin film of sealant on the seals and oring to eliminate the leak. Did they trouble shoot it to what is leaking? The cam seals, the orings, or the cam cover gasket corner.
     
    thorn likes this.
  3. thorn

    thorn F1 Rookie

    Aug 7, 2012
    2,613
    Tallahassee, FL
    There are spots next to the seals that require RTV... Have they properly applied it?
     
  4. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    26,949
    Austin TX
    Full Name:
    Brian Crall
    The seal almost never leaks. Terrible case of bad diagnosis repeated here again and again. The leakage is at the juncture of the end of the valve cover gasket and the O ring on the seal housing. The gaskets are almost uniformly poorly cut and either ooze out of place when the cover is tightened down or they cut the O ring because they are poorly shaped. There was a TSB to show how to do a modification to the cover and additionally it requires some hand trimming of the gasket to prevent it.

    Those factory sealing methods are mostly gone with most of those of us who were working on them in 1983 or never known by the kids working on them now.
     
  5. yelcab

    yelcab F1 Veteran
    Consultant

    Nov 29, 2001
    9,906
    San Carlos, CA
    Full Name:
    Mitchell Le
    I have seen the seals leak on 308/328 and even on a 360. It is true that the valve cover gasket at the far end will leak if not cut properly, and installed with a dab of sealant. That is the majority of the leaks, but I have seen seals leak.
     
  6. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    26,949
    Austin TX
    Full Name:
    Brian Crall

    43 years doing this now and that is a new one to me.
     
    2NA likes this.
  7. yelcab

    yelcab F1 Veteran
    Consultant

    Nov 29, 2001
    9,906
    San Carlos, CA
    Full Name:
    Mitchell Le
    … and that is why I asked the original poster if they have troubleshot the issue to eliminate the seals or valve cover gasket ...
     
  8. Banzairacer

    Banzairacer Karting

    Aug 24, 2017
    233
    San Diego, CA
    Full Name:
    Sanjeev Thohan
    yes there was a throroufh troubleshoot and removal and replacement of the new seals and gaskets. Still the camshaft closest to the firewall is leaking. Frustrating.
     
  9. Banzairacer

    Banzairacer Karting

    Aug 24, 2017
    233
    San Diego, CA
    Full Name:
    Sanjeev Thohan
    Why would the leak be in the bank closest to the firewall. If both are not machined well or are cut/ pinching wouldn’t we expect that to occur in both sets of gaskets - or is there A particular issue I’m missing.
    Thanks for the insights. This is new to me.
     
  10. Banzairacer

    Banzairacer Karting

    Aug 24, 2017
    233
    San Diego, CA
    Full Name:
    Sanjeev Thohan
    RTV?? Sorry
     
  11. thorn

    thorn F1 Rookie

    Aug 7, 2012
    2,613
    Tallahassee, FL
    One example here. It's not applied *everywhere*, btw (meaning, not on the full surface of the gasket.)

    And as others mentioned, you need to properly trim the gaskets.
     
    308 milano likes this.
  12. Banzairacer

    Banzairacer Karting

    Aug 24, 2017
    233
    San Diego, CA
    Full Name:
    Sanjeev Thohan
    Thanks. I figured it may be but wanted to be sure.
    Looks like it’s the cam seal gasket itself.
    Is it possible the camshaft is not balanced properly and vibration is causing the issue on use.
    Is there a bearing that may need replacement?

    just trying to understand the potential contributing factors that is causing 1/4 to fail?
     
  13. thorn

    thorn F1 Rookie

    Aug 7, 2012
    2,613
    Tallahassee, FL
    Dude. You're completely overthinking this at the moment.

    Pull the cover, and see how the gasket has seated, if it has been trimmed, how the seal looks, if the seal was installed properly, and if sealant was applied properly. Confirm all of these things before you start wondering about an imbalanced camshaft.

    As to "why only 1 bank?".... because each bank has it's own seal, gasket, etc. I've had the front-most bank leak on mine, and only that bank. Guess what it wasn't? A bearing or wonky camshaft.
     
    Rifledriver likes this.
  14. Banzairacer

    Banzairacer Karting

    Aug 24, 2017
    233
    San Diego, CA
    Full Name:
    Sanjeev Thohan

    Thanks will have the shop boys look at it simpler. When in doubt okhams razor.
     
  15. 2NA

    2NA F1 World Champ
    Professional Ferrari Technician Owner Consultant

    Dec 29, 2006
    17,694
    Twin Cities
    Full Name:
    Tim Keseluk
    It's a difficult place to see what you're doing. With everything assembled and A/C compressor installed, even more so.
     
    Rifledriver likes this.
  16. johnk...

    johnk... F1 Veteran
    Owner

    Jun 11, 2004
    7,958
    New England/FL
    If it is actually the seal that is leaking you need to inspect the cam shaft to see if the surface the seal rides against is damaged.
     
  17. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    329
    Afternoon all,
    Fully agree! Mine have leaked after checking valve clearance and it was always the poor triming of the gasket or sealant, never the seal.

    Just my experience.

    John
     
    2NA likes this.
  18. kcabpilot

    kcabpilot Formula Junior

    Apr 17, 2014
    909
    California SF area
    Full Name:
    Paul
    You guys need to clarify if you're talking about the cam seal or the o-ring in the seal carrier. Two different things.
     
  19. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    329
    Afternoon Paul,
    I'm talking about the seal, mine have never leaked, the O-rings haven't leaked either. Leaks always came from the gasket as it touches the O-ring. This was due to poor trimming of the gasket at that point and not enough sealant on the same spot. I'm not talking about a lot of sealant, just enough to fill in the space between the gasket and the O-ring. This also keeps the gasket from moving when installing the cover.

    John.
     

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