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F250 timing alignment after tensioner pulley change

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  • F250 timing alignment after tensioner pulley change

    Hi all, new here as well as to 4 stroke outboards, especially 4 cam Yamahas. I'm helping a friend with a 2007 F250. His motor sprung a leak in the casing under the tensioner pulley. He managed to repair the leak by removing the pulley and using some epoxy; he also replaced the pulley at this time. He did this repair without removing the flywheel or belt, and says he did not move any of the cams or turn the flywheel. However the timing marks do not line up according to the pics in the manual (which he did not have at the time of the repair but we have one now). The marks (referring to the single and the double lines on the starboard/port camgears) don't seem far off (sorry, no pics at this time). Just how close are those marks supposed to be, and can we do this alignment without pulling the flywheel and the heads? And does the intake or exhaust cam get turned?

    Thanks for any suggestions.

    Paul

    (and yes I asked this question over on THT and someone referred this site to me)

  • #2
    cause now you be pooched.
    now you remove the cams, VERY CAREFULLY.
    then you rotate the crank and align the marks correctly from the drive sprocket to the block casting.
    now you install the cams just like the SM pictures.
    now install the belt with all the marks lined up on the drive sprocket and the cam sprockets.
    have the tensioner locked back.
    the easy way is to use the center aft idler as the last part installed when installing the belt.
    DO NOT move the crank until you know POSITIVLY where the valves are.
    not only can damage occur due to valve/piston interference but the valves may not clear each other if the cams are incorrect.
    not the first v6/v8 I have ever had brought to me due to incorrect procedure.

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    • #3
      I figured we were pooched.

      On this motor would it just be easier to pull the heads rather than f with the cams?

      Thanks rodbolt. You didn't make my day but it's still good to know.

      Paul

      Comment


      • #4
        Originally posted by stormdog View Post
        On this motor would it just be easier to pull the heads rather than f with the cams?
        it must take a very special wrench
        to remove / install the cylinder head bolts with the camshafts installed

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        • #5
          I use a heavy rubber band to choke the belt on the crankshaft.
          Help's keep it from moving.

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          • #6
            it has already moved.
            the cams and crank MUST be properly positioned BEFORE the belt is removed.
            the only way to position the crank if done improperly is to CAREFULLY loosen the cam bearing caps.
            1/4 turn at a time on each.
            do it wrong and you hear a CRACK.
            the CRACK just notified you the cam broke.
            remove the cams,position the crank,install the cams and go play.
            it aint hard or I would be out of a job.

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            • #7
              To me it sounds more like a "dink". Then the cam shaft is in two pieces. Amazing how brittle it is.

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              • #8
                Originally posted by fairdeal View Post

                it must take a very special wrench
                to remove / install the cylinder head bolts with the camshafts installed
                You normally come of with photos of anything and everything. I would like to see a photograph of said special wrench. Must make the bolts flexible so they can slide out from under the shafts.

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                • #9
                  Originally posted by fairdeal View Post

                  it must take a very special wrench
                  to remove / install the cylinder head bolts with the camshafts installed
                  That's why I prefer my two strokes, still trying to wrap my head around this beast!

                  Again, thanks for the comments and suggestions, we will be moving forward on this over the coming weekend.

                  Keep the good humor coming!

                  Paul

                  Comment


                  • #10
                    it aint hard.
                    if it was I would be out of a job.
                    maybe someone from a c*****n may take it yet.
                    just go SLOW.
                    back off the cam caps 1/4 turn each.
                    otherwise you may hear the dreaded TINK.

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                    • #11
                      Aint no hill for a hill climber.

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                      • #12
                        Yesterday we got down to work, it didn't take long to discover we would not luck out: There was a mangled cam follower on an intake valve. We made the decision to pull the motor off the boat and move it inside, right now it's still hanging from the hoist while my buddy either builds or buys a stand. I'll be back once the motor is stabilized and we get the heads off and get a better feel for the extent of damages.

                        Thanks to all for the advice and suggestions.

                        Comment


                        • #13
                          would all be good........ except that motor does not use cam followers.
                          it uses shims and buckets.

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