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Adjusting Valves

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  • Adjusting Valves

    '85 Mercruiser V6 4.3l
    Anyone know a idiot proof way to adjust the valves or have a link on how to? I would like to do it with the engine off if possible

  • #2
    Re: Adjusting Valves

    Have you looked in the maintenance manual?
    You can find it in the adults only thread at the top of the page.
    From Mercruiser:
    Anyone who uses a service procedure and/or tool, which is not recommended by the manufacturer, first must completely satisfy himself that neither his nor the productís safety will be endangered by the service procedure selected.

    Comment


    • #3
      Re: Adjusting Valves

      Anyone know a idiot proof way to adjust the valves
      NO! No such thing.
      Don S.


      Please, no PM's (Private Messages) regarding boat/engine problems.
      That is what the forums are for.
      Only forum/moderator issues will be answered in PM's.

      Comment


      • #4
        Re: Adjusting Valves

        Originally posted by Don S View Post
        NO! No such thing.
        Ok, I'll give it a shot. just looking for simplicity. Is there anything else I should look for or do that the manual doesn't mention?

        Comment


        • #5
          Re: Adjusting Valves

          If you are using the engine off method. When you tighten down the rocker arms to remove the play in the pushrod. Just roll the lifter back and forth between your fingers. The second it stops turning while you are tightening the lifter. STOP. That is zero lash. It will loosen up but DO NOT tighten anymore to stop the lash. DO it one time and one time only. Then go your 3/4 to 1 full turn on the lifter and call it good for that lifter and move on to the next.
          Don S.


          Please, no PM's (Private Messages) regarding boat/engine problems.
          That is what the forums are for.
          Only forum/moderator issues will be answered in PM's.

          Comment


          • #6
            Re: Adjusting Valves

            Here is a paste from another site. It states one full turn and that I may not agree with, 3/4 may be better. I've used this method before, seems to work fine for me on my race car which is also a chevy product.

            Here is the valve adjustment procedure:

            Remove rocker arm cover.
            Rotate engine until mark on torsional damper is aligned with "0" mark on timing tab fastened to crankcase front cover. To ensure engine is at No. 1 cylinder firing position, place fingers on No. 1 cylinder valves as the mark on damper approaches the "0" mark on timing tab. If valves are not moving, engine is in the No. 1 cylinder firing position. If valves are moving, engine is in the No. 4 cylinder firing position and should be rotated one revolution.
            With engine in No. 1 cylinder firing position, adjust the following valves:

            Exhaust valves 1, 5 and 6.
            Intake valves 1, 2 and 3.
            NOTE: Even numbered cylinders are in the left bank and odd numbered cylinders are in the right bank, when viewed from front of the engine.

            Back off adjusting nut until lash is felt at pushrod, then tighten nut until all lash is removed. This can be determined by rotating pushrod while turning adjusting nut. When all lash is removed, tighten adjusting nut one full additional turn to center lifter plunger.
            Crank engine one full revolution until mark on torsional damper and "0" mark on timing tab are again in alignment. This is the No. 4 cylinder firing position. With engine in this position, adjust the following valves:

            Exhaust valves 2, 3 and 4.
            Intake valves 4, 5 and 6.
            Install valve covers and related components, then start engine and check timing and idle speed.

            Comment


            • #7
              Re: Adjusting Valves

              Ok. thanks guys. I'll give it a go this week.

              Comment


              • #8
                Re: Adjusting Valves

                Originally posted by Don S View Post
                If you are using the engine off method. When you tighten down the rocker arms to remove the play in the pushrod. Just roll the lifter back and forth between your fingers. The second it stops turning while you are tightening the lifter. STOP. That is zero lash. It will loosen up but DO NOT tighten anymore to stop the lash. DO it one time and one time only. Then go your 3/4 to 1 full turn on the lifter and call it good for that lifter and move on to the next.
                Don,
                I already have the intake manifold back on, so no chance at getting to the lifters. Can I use your method with just removing play in the pushrods?

                Comment


                • #9
                  Re: Adjusting Valves

                  Don is referring to the push rods that you see under the valve cover.
                  Intake has nothing to do with it.
                  NO PERSONAL QUESTIONS, THIS IS WHAT THE FORUM IS FOR.

                  Comment


                  • #10
                    Re: Adjusting Valves

                    Originally posted by Bt Doctur View Post
                    Don is referring to the push rods that you see under the valve cover.
                    Intake has nothing to do with it.
                    10-4 thanks! I do need to do them in a certain order though right?

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                    • #11
                      Re: Adjusting Valves

                      yep certain order so you're adjusting each valve when it's normally closed

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                      • #12
                        Re: Adjusting Valves

                        Originally posted by Bubba1235
                        As no one mentioned it, only adjust the valves on an engine that is completely warmed up.
                        How am I suppose to do that if I had everything apart and the valves aren't adjusted from removing the heads? The last thing I want is to put a rod through a piston or cause damage to something!

                        Comment


                        • #13
                          Re: Adjusting Valves

                          You do not have to warm an engine to adjust the valves statically.
                          Don S.


                          Please, no PM's (Private Messages) regarding boat/engine problems.
                          That is what the forums are for.
                          Only forum/moderator issues will be answered in PM's.

                          Comment


                          • #14
                            Re: Adjusting Valves

                            Originally posted by Don S View Post
                            You do not have to warm an engine to adjust the valves statically.
                            Ok. Should I re-adjust them though after the engine is warm? I hope to get it done this week. Too damn hot out to work in the boat right now!

                            Comment


                            • #15
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                              Re: Adjusting Valves

                              Originally posted by 505callyourball View Post
                              With engine in No. 1 cylinder firing position, adjust the following valves:

                              Exhaust valves 1, 5 and 6.
                              Intake valves 1, 2 and 3.
                              NOTE: Even numbered cylinders are in the left bank and odd numbered cylinders are in the right bank, when viewed from front of the engine.
                              .
                              Just curious, when you're doing this, how do you know which is intake valve and which is exhaust valve? Are there visibly different?

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