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  1. #1
    Join Date
    Aug 2011
    Location
    Marblehead, MA
    Posts
    27

    Default Block off plate manifold/riser gasket

    This fully closed system is new to me, I've been dealing with RWC until now. I just pulled the riser off to inspect and see that there is a solid block-off plate in between the manifold and riser, actually between the riser and whatever you call the extension that is about 2.5" wide where the coolant hose is attached... anyway, I am wondering where I can find and what gasket I should use. Everything I've seen in gaskets has port holes, 1 or three. Do hey make a solid 3" gasket for fully closed systems? or can I use a single hole gasket with some permatex or some kind of gasket sealer?

    Also, I was quite surprise that I could almost undo the nuts by hand! What are the torque specs on riser nuts? Mine are studs with nuts, is that normal for Crusader? Again, all new to me coming from Ford PCM.
    thanks for any input!
    1986 20' Shamrock Openfish
    Crusader 270 (not installed yet)

  2. #2
    Join Date
    Sep 2008
    Location
    Maryland - USA
    Posts
    8,675

    Default Re: Block off plate manifold/riser gasket

    The 'donut' is called a water outlet adapter...it is how the coolant is removed from the cast iron manifold assembly. You likely has risers and elbows. They typically are raw water cooled and will have a 4-7 year service life...if you don't know how old they are, now is a great time to replace them.

    on the gaskets, you can use either at the block off plate. on the raw water side joints, use the one hole gaskets...use the three hole gaskets on the coolant side. make sure the flanges are flat and you can use a thin coat of permatex #3 if you want. you will find the gaskets have a tab or tabs...these need to go 'up' for proper orientation (either ~ 12 o'clock or ~10 and 2 o'clock).

    the studs are typical crusader...and can be reused if in good shape...many use a thin smear of anti-seize on the studs during reassembly. the copper washers are sealing washers and should be replaced. 25 ft*lbs is the torque spec...and if I remember correctly, a crow's foot helps a bunch...and don't forget to correct for it when setting the wrench...

  3. #3
    Join Date
    Aug 2011
    Location
    Marblehead, MA
    Posts
    27

    Default Re: Block off plate manifold/riser gasket

    Quote Originally Posted by makomark View Post
    on the gaskets, you can use either at the block off plate. on the raw water side joints, use the one hole gaskets...use the three hole gaskets on the coolant side. make sure the flanges are flat and you can use a thin coat of permatex #3 if you want. you will find the gaskets have a tab or tabs...these need to go 'up' for proper orientation (either ~ 12 o'clock or ~10 and 2 o'clock).
    Thanks on the gasket info! I was hoping my thoughts were on target, apparently so.

    For exhaust I just have the "donut", and thanks for real part name by the way, and elbows. I plan to get risers in there, my waterline is close and I don't want to have water back up.

    I appreciate the tips, thanks!
    1986 20' Shamrock Openfish
    Crusader 270 (not installed yet)

  4. #4

    Default Re: Block off plate manifold/riser gasket

    Having learned the hard way on our 8.1s, you will need to retorque the bolts/nuts for the risers/elbows after one or maybe two heat cycles. Our elbows bolt directly to the manifolds. Do not skip this step.

  5. #5
    Join Date
    Sep 2008
    Location
    Maryland - USA
    Posts
    8,675

    Default Re: Block off plate manifold/riser gasket

    2X on the re-torque...for all of the exhaust parts, too!

    on the need for risers, the 'new' installation manual is easy to find on the www...it applies to the older installs as well. just beware that if you add them, you need to make sure you have clearance under the existing engine box cover. You will likely need new exhaust hose, too...

  6. #6
    Join Date
    Jun 2008
    Location
    Island Heights, NJ,
    Posts
    3,544

    Default Re: Block off plate manifold/riser gasket

    Quote Originally Posted by Peter Schalck View Post
    Thanks on the gasket info! I was hoping my thoughts were on target, apparently so.

    For exhaust I just have the "donut", and thanks for real part name by the way, and elbows. I plan to get risers in there, my waterline is close and I don't want to have water back up.

    I appreciate the tips, thanks!
    A "close" waterline is a Shamrock "feature"...
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280

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