Announcement

Collapse
No announcement yet.

Elbow/Spacer Gasket Question-gctid403850

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Elbow/Spacer Gasket Question-gctid403850

    Hi All,

    I had a noisy exhaust shutter/flapper and decided to pull the elbows for inspection and check the exhaust manifolds at the same time as replacing the shutters. My engine is a 1993 Mercruiser 5.0 Alpha 1. I believe it also has the warm water manifold setup with the hoses from the thermostat housing only going to the bottom of the exhaust manifolds. I ended up replacing both manifolds, elbows/risers,hardware,shutters and 3 inch spacers. My question is when it comes to the spacer and elbow gaskets, which ones apply to my manifold setup restricted or open? I came across a Mercruiser bulletin which pointed me toward open gaskets below the spacers and above the spacers under the elbows. The gaskets that were there when I pulled it apart were the restricted type. So which ones are the correct gaskets? Open, restricted, or some combination of the two? Also does anyone have the correct torque specs for the exhaust manifold to head bolts?

    Thanks

    Matt

    #2
    Ding Dang wrote:
    ... Open, restricted, or some combination of the two?...
    When I researched it my take away was it didn't matter so much as using the same gasket type on both sides.

    Comment


      #3
      Do you have raw water cooling or a closed system.

      It sounds to me like your manifolds are raw water cooled... only 1 hose going to the manifold. If this is the case then you should use the unrestricted type. I would use the same type you took off. If in any doubt check with your parts supplier or a local mechanic. You definately don't want to use the wrong gaskets.

      Good luck

      Chris

      Comment


        #4
        Confirm this recommendation but this is how I would do it:

        * Open gasket between the manifold and the spacer :

        http://www.marinepartshouse.com/prod...et-open-p-1843

        * Restricted gasket between the spacer and the elbow :

        http://www.marinepartshouse.com/prod...gaskets-p-1674

        The spacers are merely an extension of the cooling jacket in the manifold which are fully open. The restriction always occurs at the elbow junction.
        " WET EVER "
        1989 2459 TROPHY OFFSHORE 5.8L COBRA / SX
        mmsi 338108404
        mmsi 338124956
        "I started with nothing and still have most of it left"

        Comment


          #5
          Matt, we need more info. Closed Cooling system, or Open Cooling system????

          Do a search similar to this one.

          Also, go to Merc's web site, and use your engine serial number.

          It will make quite a difference as to the plumbing and porting of the exhaust manifolds, the risers, and how the spacers are not only blocked off, but how they are plumbed.

          For example:

          In this scenario, the manifolds are fed from one location only (continuous by-pass sea water), and the risers are fed from another (T-stat released sea water).

          Since the mans are single fed, the porting between the man and riser must be "open" to obtain flow up and out the riser, and into the exhaust flow.

          If you installed a riser "spacer", it too must be open top and bottom.

          If closed or restricted underneath the spacer, the manifolds would now have reduced flow that would cause them to over-heat.... in fact, it would unbalance the entire system.



          .
          Rick E. Gresham, Oregon
          2850 Bounty Sedan Flybridge model
          Twin 280 HP 5.7's w/ Closed Cooling
          Volvo Penta DuoProp Drives
          Kohler 4 CZ Gen Set

          Comment


            #6
            Matt, we need more info. Closed Cooling system, or Open Cooling system????
            the hoses from the thermostat housing only going to the bottom of the exhaust manifolds.
            He stated the flow goes from the t-stat housing to the bottom of the exhaust manifolds, this indicates raw cooled.
            " WET EVER "
            1989 2459 TROPHY OFFSHORE 5.8L COBRA / SX
            mmsi 338108404
            mmsi 338124956
            "I started with nothing and still have most of it left"

            Comment


              #7
              Thanks for the info guys. Sorry, I do have a raw water system . There are two feeds port and starboard, comming from the thermostat housing to the bottom of the manifolds only. There are no feeds to either riser. Here is a link to the bulletin I was talking about. http://www.boatfix.com/merc/Bullet/99/99_10.pdf

              My confusion comes from the info in the bulletin and what I found on my manifold assy when I took it apart. As I read it the bulletin applies to my manifold setup as stated on page 2 under 4a. From the bulletin 4a. Raw water cooled engines with all the water from the thermostat housing going to the

              90-degree fitting on bottom of the exhaust manifold:

              Use P/N 27-863726 Gasket ÔÇô 4 Slot between the exhaust manifold and the exhaust

              elbow.

              If the engine has 3 in. (76 mm) or 6 in. (152 mm) risers, use P/N 27-863726 Gasket ÔÇô

              4 Slot between the riser and the exhaust manifold and exhaust elbow "
              27-863726 is the open gasket. The gasket I found during disassembly was the restrictor gasket. I am thinking that either the last person to change the manifolds and elbows either 1. used the wrong gaskets, 2. Did not know about the bulletin, 3. The bulletin has been updated after the one I found. 4. I am reading the bulletin incorrectly.

              Matt

              Comment


                #8
                Matt, can you find the correct schematic, and post it for us?

                I'm at a loss without the correct schematic.

                Plus, just what are they calling a restrictor gasket?

                Is this their open gasket?



                Is this their restricted gasket?



                Ding Dang wrote:
                I do have a raw water system .
                • 1 wrote:
                • There are two feeds port and starboard, comming from the thermostat housing to the bottom of the manifolds only.
                • There are no feeds to either riser. Here is a link to the bulletin I was talking about. http://www.boatfix.com/merc/Bullet/99/99_10.pdf
                • My confusion comes from the info in the bulletin and what I found on my manifold assy when I took it apart. As I read it the bulletin applies to my manifold setup as stated on page 2 under 4a. From the bulletin 4a. Raw water cooled engines with all the water from the thermostat housing going to the 90-degree fitting on bottom of the exhaust manifold: Use P/N 27-863726 Gasket ÔÇô 4 Slot between the exhaust manifold and the exhaust elbow.
                • If the engine has 3 in. (76 mm) or 6 in. (152 mm) risers, use P/N 27-863726 Gasket ÔÇô4 Slot between the riser and the exhaust manifold and exhaust elbow " 27-863726 is the open gasket.

                  The gasket I found during disassembly was the restrictor gasket.
                • I am thinking that either the last person to change the manifolds and elbows either 1. used the wrong gaskets, 2. Did not know about the bulletin, 3. The bulletin has been updated after the one I found. 4. I am reading the bulletin incorrectly.



                • 1 wrote:
                • Two per manifold, or two total?
                • This suggests to me that the gaskets must be fully open.

                  BTW, not sure if this makes any difference, but this is a January 2001 bulletin.
                • The schematic would sure help here.

                  Some T-stat housings divert two means of sea water shown in the schematic that I posted earlier.

                  Note the 4 outlets on the T-stat housing.

                  2 outlets are used for the continued supply that feeds the manifolds. IOW, all sea water that the engine does not see!

                  2 outlets direct the spent sea water that is leaving the engine (via the thermostat), and on to the risers.

                  However, you say that your risers ports are not being used.... correct?
                • Again, need to see the schematic.

                  If the majority of the sea water pump supply is ported to the manifolds, and if the risers are NOT ported, you certainly do not want the man/riser transfer ports restricted by a gasket. OMC, Volvo or Merc....., it should not matter, IMO.
                • Need to see the schematic.

                  The bulletin mentions three gasket styles. All standard V6 and V8 gasoline engines with center outlet exhaust manifolds.

                  P/N 27-863726 Gasket ÔÇô 4 Slot.

                  P/N 27-863724 Gasket ÔÇô Restrictor (with 2 holes and 2 slots). The 2 holes always go fore and aft.

                  P/N 27-863725 Gasket ÔÇô Block-off (without holes or slots). This gasket stops coolant flow.




                Matt, if this bulletin is correct for your engine model, and if we read this literally, it would imply that the riser ports are not being used in 4a, but are being used in 4b.

                [COLOR]"#0000FF" wrote:


                4a. Raw water cooled engines with all the water from the thermostat housing going to the 90-degree fitting on bottom of the exhaust manifold: Use P/N 27-863726 Gasket ÔÇô 4 Slot between the exhaust manifold and the exhaust elbow. If the engine has 3 in. (76 mm) or 6 in. (152 mm) risers, use P/N 27-863726 Gasket ÔÇô 4 Slot between the riser and the exhaust manifold and exhaust elbow.

                4b. Raw water cooled engines with the bypass water from the thermostat housing going to the fitting on the exhaust elbow and the warm water from the thermostat housing going to the 90-degree fitting on bottom of the exhaust manifold:

                Use P/N 27-863724 Gasket ÔÇô Restrictor between the exhaust manifold and the exhaust

                elbow.

                If the engine has 3 in. (76 mm) or 6 in. (152 mm) risers, use P/N 27-863724 Gasket ÔÇô

                Restrictor between the riser and the exhaust elbow. Use P/N 27-863726 Gasket ÔÇô 4 Slot

                between the exhaust manifold and riser.[/COLOR]
                Rick E. Gresham, Oregon
                2850 Bounty Sedan Flybridge model
                Twin 280 HP 5.7's w/ Closed Cooling
                Volvo Penta DuoProp Drives
                Kohler 4 CZ Gen Set

                Comment


                  #9
                  Thanks Rick for trying to help.

                  You have it correct with your pictures and descriptions of open and restricted gaskets.

                  There are two feeds total, one to the bottom of each manifold.

                  Riser ports for cooling hoses are NOT being used.

                  Yes I noticed the date on the bulletin, and I wonder if it is still valid.

                  The link below contains a schematic for my cooling system setup. middle of the page.

                  http://www.perfprotech.com/store/art...ling-tips.aspx

                  Thanks again!

                  Matt

                  Comment


                    #10
                    Ding Dang wrote:


                    There are two feeds total, one to the bottom of each manifold.

                    Riser ports for cooling hoses are NOT being used.

                    The two statements above, and this double outlet ONLY T-stat housing, pretty much does it for me.

                    IMO, the ports need to be as open as they can be.

                    (the notes for each port here explain the sea water path)


                    Rick E. Gresham, Oregon
                    2850 Bounty Sedan Flybridge model
                    Twin 280 HP 5.7's w/ Closed Cooling
                    Volvo Penta DuoProp Drives
                    Kohler 4 CZ Gen Set

                    Comment


                      #11
                      Thanks Rick excellent information.

                      That is what I was leaning toward but it is good to know for sure.

                      Happy Boating!

                      Matt

                      Comment


                        #12
                        Ding Dang wrote:
                        Thanks Rick excellent information.

                        That is what I was leaning toward but it is good to know for sure.
                        Matt, I'm fairly certain that you'll want the fully open gaskets as per "4a" in the bulletin......, but just as an FYI, that was my opinion only.

                        If you have any reservations at all, search this a bit further.

                        .
                        Rick E. Gresham, Oregon
                        2850 Bounty Sedan Flybridge model
                        Twin 280 HP 5.7's w/ Closed Cooling
                        Volvo Penta DuoProp Drives
                        Kohler 4 CZ Gen Set

                        Comment


                          #13
                          2850Bounty wrote:
                          Matt, I'm fairly certain that you'll want the fully open gaskets as per "4a" in the bulletin......, but just as an FYI, that was my opinion only.

                          If you have any reservations at all, search this a bit further.

                          .
                          UPDATE

                          After putting it back together with the open gaskets and taking the boat out several times there were no issues. The engine runs slightly cooler, (about 160-170 vs 170-180) than it did before the new manifolds and elbows. I am not sure if this is due to the open gaskets being installed over the originally installed restricted gaskets or the brand new manifolds, elbows and spacers. The elbows seem a little warmer to the touch at idle but at cruising speed the temp of the elbows is lower than it is at idle speed. I think this could be a result of the open gaskets being installed. Thanks to all who replied for the advice, input and help.

                          Happy Boating!

                          Matt

                          Comment

                          Working...
                          X