348 Valve Cover Leak Try #3 | FerrariChat
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348 Valve Cover Leak Try #3

Discussion in '348/355' started by 348steve, Mar 18, 2023.

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  1. 348steve

    348steve Karting

    Jul 18, 2018
    151
    Full Name:
    Stephen G
    #1 348steve, Mar 18, 2023
    I am going to try for the 3rd time to seal the valve covers. They appear to leak from the quintessential front side areas adjacent to the o-rings. On the first try I used the highly suggested ThreeBond 1211 silicone, applying a careful amount to both sides at the ends of the gaskets and adjacent to the o-rings. Yes, the gaskets wandered when I torqued the cover down. My bad.

    On the second try I cleaned and prepped again till perfect, then used a small drop of ethyl cyanoacrylate to hold the gasket to the head and applied a small amount of ThreeBond in the same places. I then placed the cover and gently hand tightened to let it dry over night before torquing it down to spec. I read about this method in this forum. The gasket It still leaks.

    Note: I am able to carefully examine the leak to confirm it is not from the newly installed cam seals, the oil clearly originating each time from these difficult spots near the o-rings.

    Note #2: When the cover was first removed I took photos of the area as the cover gently came off to note how the previous person was so successful. Those photos are shown here. Whatever they did worked perfectly!

    Any ideas will be highly appreciated!


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    Any ideas will be highly appreciated!



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  2. Ferrarium

    Ferrarium F1 Veteran
    Sponsor Rossa Subscribed

    Jul 28, 2018
    5,728
    Central NJ
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    Eric
    #2 Ferrarium, Mar 18, 2023
    The o-ring groove where the valve cover and the block meet is razor sharp. Go ahead, stick your fingertip on there and see. When you clamp it it pinches the o-ring and because its so sharp it nicks the o-ring just a tad and that's all it takes to leak. Take a jewelers file and round off those razor sharp castings ESPECIALY on the vale cover side. Its a freaking razor, check for your self. The actual TSB for that shows it basely hogged out with a round file then fill it with honda bond. I was too scared to do that drastic a filing job so I just took off the razor edges. Finger's crossed.

    Have a close look at the oring, I bet you see abrasion from the casting. its not cut... just abraised. Anything other than a perfect o-ring will leak as you know. Its really easy to miss the marks on the oring.
     
    V4NG0 likes this.
  3. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    37,106
    Cowboy Capitol of the World
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    Brian Crall
    #3 Rifledriver, Mar 18, 2023
    Last edited: Mar 18, 2023
    You are doing a couple of things wrong.
    A. Three Bond 1211 was a great product 20 years ago. Formula was changed and its garbage now. Use grey or black ultra silicone or Honda Bond 4. I am sure there are others but those work for me. Leave the superglue in the house. It has no business on gaskets. Make sure all surfaces are perfectly dry.
    B. As said, the ends of the O ring grooves need to be radiused. Don't be shy. use a 1/4 inch or so round file and make the radius's pretty big. Trim the gaskets so they do not touch the O ring or the O ring housing. Use the sealant to fill the gaps. Lightly tightening the valve covers at the ends until sealant sets pretty much makes leaks a certainty. Never do that. It is certain to leave an air gap somewhere that oil can leak through. When final tightening end nuts use finger to hold gasket in place so it doesnt squirt out but make sure all are tight prior to sealant setting up.
    C. Use the O rings Ricambi America sells. They are closer than any to what Ferrari supplied us back then. All the other O rings out there are not the same including what Ferrari is now supplying. Replacing valve covers gaskets without replacing O rings is a waste of time.

    Its a lousy design. The engineers had their heads up their ass when they designed it and Ferrari had us jumping through all sorts of hoops trying to fix warranty claims. Be really happy if it goes together without leaking but do not expect leak free operation until the next belt job.
     
    V4NG0 and SoCal1 like this.
  4. 348steve

    348steve Karting

    Jul 18, 2018
    151
    Full Name:
    Stephen G
    #4 348steve, Mar 30, 2023
    Thanks Rifledriver, sounds like good advice. I'll give it one more try, I'll get some Honda bond, I'll trim the gaskets if required, I'll torque it down without letting it dry and I'll leave the crazy glue in the house ... all ideas I received through this forum :). Fingers crossed!!!!
     

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