Intake manifold leak

Discussion in 'Small Block Tech' started by partsrparts, Feb 21, 2021.

  1. partsrparts

    partsrparts Silver Level contributor

    Ok, I've gotten to the point where the only things left are to prime the oil system and install intake and valve covers.
    I have always had the intake leak oil at the 4 corners no matter what intake or what gaskets used. Stock 4bl leaked with metal pan gasket, stage1 leaked with metal pan gasket and with composite gaskets. I use the TA splash guard with the composite.
    I've seen alot of posts on how to do the intake gaskets but of course I've done searches on this forum all morning long and can't find any of them.
    With the intake sitting on the motor with the composite gaskets I have a 1/4" gap at the front and back where the end seals go without them installed, the end seals measure 1/4" so I need to run a bead of "right stuff" on top of the seals and I always put a blob where the seals meet the heads, but I have always get a leak at the corners.
    I'm using the SP3 this time.
    Keith finally2.JPG
     
  2. Mark Demko

    Mark Demko Well-Known Member

    Nice heavy bead of RTV on the rails, make sure its smooshed into the crevice where the rail and head meets at the 4 corners.
     
  3. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Keith,
    If you are getting leaks in the corners, it is likely because you are not getting the RTV under where the heads overhang the rails. Look at the picture you posted. Even if you use the rubber seals, you must put some RTV under that overhang. The rubber seal tucks under there, but you still need RTV there, doesn't take much. Jim Weise goes into detail about Intake sealing in this thread, it's a good read,

    https://www.v8buick.com/index.php?threads/installing-a-new-intake.15987/#post-110749
     
  4. theroundbug

    theroundbug Well-Known Member

    FWIW, directions that come with those metal gaskets just say to put rtv around the ports, I follow the bead all the way around. Never had a leak.

    Gotta use those rubber seals with some rtv as well. They tuck in the corners nice and tight
     
  5. buicksWILD

    buicksWILD Well-Known Member

    Some people don't run the rubber seals and instead lay down a nice bead of silicone.
     
    TrunkMonkey likes this.
  6. Fox's Den

    Fox's Den 355Xrs

    I ran the bead across both ends no rubber seals I copper sprayed the gaskets so they would stay suck to the head when I dropped the intake on.
     
  7. DasRottweiler

    DasRottweiler -BuickAddict-

    Iron Stage 1 heads, cut on both sides ,NOS Steel head gaskets , Coppercoat both sides, no rubber as intake sits lower, just a bead of Right Stuff on the "China Walls". JIM
     
  8. partsrparts

    partsrparts Silver Level contributor

    Thanks for the input everyone! I will be doing it shortly, plan on dropping it in tomorrow.
    Keith
     
  9. MrSony

    MrSony Well-Known Member

    I cut the ridge off of the top of the rubber seals. First time I did that no leaks.
    Also goop rtv under the heads. Make sure it doesnt squeeze into the lifter valley.
     

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