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Thread: Riser gasket?

  1. #1
    J230SX454MAG
    First off great site here!
    I have a 454MAG with EMI Thunder Exhaust. Riser gasket is starting to seep. (noticeable on outside) Question is do I need to go with a EMI gasket set? This set leaked after 75 hours, so is there a better alternative? Also, do you use a permatex gasket sealer or anything or just install dry?
    I'm not much of a gear head / mechanic, but with some explanation I can usally get my bearings straight to tackle a job like this.
    Thanks in advance and again, neat site!

  2. #2
    Dennis Moore
    Mercruiser was having the same problem and sent out a service bulletin specifying the use of Locktite Flange Sealer #510 to be applied to the gaskets. It works very well. The Mercruiser part # is 92-804874. Follow the instructions on the tube.
    Sincerely
    Dennis Moore

  3. #3
    J230SX454MAG
    Thanks Dennis!
    Not really a gear head by any means but thought I could tackle this one!
    Any certain gasket material have prefrence over others here on the board?

  4. #4
    razor1115
    are your risers 4" SS? I had the same problem and hopefully put a long lasting fix on - last time a gasket leaked, it was to the inside of the mainfold - engine filled with water

  5. #5
    Dennis Moore
    J230
    You are going to have to use the EMI gaskets. A little helpful hint. If you are using studs to hold the risers to the manifolds install studs that are course thread on one end and fine thread on the other. Install the course thread end into the manifolds with Loctite and use fine thread nuts on the other end. Fine thread nuts will not back off as easily as course thread nuts and you won't hve to keep retightening the nuts as often! You should also use stainless studs and nuts with a little Neversieze paste.

  6. #6
    J230SX454MAG
    razor1115,
    Mine are 4" alunimum and the gaskets as shown on EMI's web site have water passages.
    Dennis,
    Great idea with the course/fine stud. The alunimum risers on my engine are bolted on? Is that odd? I like your idea much better and will look into replacing my bolts. Thanks!
    I have Silent Choice exhaust so is there anything more to it then removing the 4 bolts and 4in rubber hose to remove the riser, or is the Silent choice in some way affiliated with the riser system to where I'd have to take out the whole Y pipe, S/C system.
    Thanks again for the help and ideas!

  7. #7
    lovemyultra
    You can also have the water ports welded, then machined flat, then the only gasket failure you can have is an exhaust leak. Not good by any account, but better then any water near the inside of your motor. All you need is the hose to connect the riser to the header, much more relaxing

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