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Correct intake manifold procedure

Discussion in 'The Garage' started by sickquad, Dec 4, 2004.

  1. sickquad

    sickquad 1/2 ton status

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    So my intake manifold has a oil and vacuum leak.

    I talked to a friend of a friend who is a GM mechanic. He told me that using silicone on the back of the manifold instead of the rubber gaskets is a bad rumor. He has experience building motors and it is his opinion that the rubber gaskets in the back of the manifold are the way to go as long as you are careful putting it together.

    What do you guys think? Any other tips or tricks so this is the last time I put it together.

    This is my third reinstall of the manifold. I found out the first one I put on had a small warp on the back of it.

    One more thing. I used the flourescent dye from AutoZone to find my leak with a black light. Highly recommend everyone buy a bottle of it since the AutoZone manager said it is not going to be a consumer item for much longer. I bought two. Work smarter not harder!!

    Thanks
    Chris
     
  2. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    ive used the rubber seal with silicone on it on 3 motors and the only one that leaked was on my truck, it has the factory cast iron manifold.
     
  3. Thunder

    Thunder 3/4 ton status

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    I always use the rubber gaskets. Usually put a little dab of black RVT in each corner.
     
  4. diesel4me

    diesel4me 1 ton status Premium Member

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    I have had to pull intakes off and throw away the rubber end seals when they popped out--I'm not saying the GM tech is wrong,but I would not use them again--I've put dozens together with just "Ultra Blue" permatex on the ends,and have had no leaks or problems.If I were to use the rubber end seals,I glue them in place with 3M weatherstrip adhesive after cleaning the block and intake with brake cleaner.But I dont think I would ever put the rubber ones in again--I dont like doing the same job twice--once is bad enough!!. /forums/images/graemlins/doah.gif
     
  5. 4x4Freak

    4x4Freak 1/2 ton status

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    I've only really had a problem with the seals once, and that was before I really knew what I was doing. I always clean the surfaces good with some laquer thinner. I smear a little bit of 3M glue on the block where the seals go, then put them on and let the glue dry for a little bit. Once they set up a little while I run a good sized bead of RTV on top of the seals and set the intake on.
     
  6. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I have never used the rubber seals and never had a leak. I always use silicone there.
     
  7. mr_beer

    mr_beer 1/2 ton status

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    [ QUOTE ]
    I always use the rubber gaskets. Usually put a little dab of black RVT in each corner.

    [/ QUOTE ]
    Same thing I did with no problems at all /forums/images/graemlins/thumb.gif
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    Edelbrock

    That shows edelbrock not recommending the rubber end seals.

    Pretty sure I've seen the same thing in the later GM service manuals, but I'm not up to finding one of them and checking.
     
  9. ryoken

    ryoken Puppy Fabricator Premium Member GMOTM Winner

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    back in the day, we would glue the end gaskets in with Catepillar gasket cement. worked fine never had a failure..

    the main problem with the gaskets is once you begin milling head surfaces that gap between block and intake will get smaller. i've seen it on small blocks before that had been rebuilt a couple times. your rest assured that rubber will squeeze out or worse, your intake ports wont seal right.. now thats obviously a small percentage of cases, but it can bite ya in the ass...

    since i saw that years ago, i've used silicone strictly and never had a failure.. and i'd guess i've done a couple hundred at work...
     
  10. sickquad

    sickquad 1/2 ton status

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    Well I asked around and it is pretty much 50/50 on wether or to use the rear gaskets. Exactly what I expected. Decisions, decisions.

    Chris
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    FWIW, I didn't mention it before, in the whopping 4 GM intake manifolds I've installed, I never used the rubber end gaskets, and have not had a problem with any of them.

    Use silicone, and don't worry about it.
     
  12. jakeslim

    jakeslim 1/2 ton status

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    why use them? The way i see it, if you use them and install them "just right", then your ok, but there is a chance they will pop out or leak. Its tough to see it the back one sets right...suck to have a leak, had that problem on a 68 Camaro I owned years ago.

    don't use them, use a nice bead of the gasket maker and be done with it. Not much room for error period. No one seems to
    have had this method leak.
     
  13. azblazer69

    azblazer69 Registered Member

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    I have had gasket maker alone leak here... I like the 3M weatherstriping adhesive with a gasket method myself... Provided you let it set up before you set the manifold on... the biggest problem with gaskets is if you slide the manifold, even a little, it slips and, leakie... If your working on an engine thats in the truck, you might consider taking the hood off... It may help you set the manifold straight down... I just glue the engine side, no glue on manifold side...
     

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