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Broken rocker arm. Seize the day to build the head?

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    Broken rocker arm. Seize the day to build the head?

    Hey all!

    I've got an 89 325iX with 232k (maybe 180k on the engine), and I broke a rocker arm. It's for the exhaust valve on the #3 cylinder, so I have to pull the head. I'd like to turbocharge this car in the future, so I am thinking this is the perfect time to do whatever work I'd need to do on the head, and maybe build it out a little while I'm at it.

    I'd like to install, if my budget permits, ARP studs, an IE 272 cam, and IE HD rocker arms, as well as OEM replacements of maintenance items (timing belt, water pump, head gasket). Are there other things that I should be looking at if I want to eventually run 11psi or so of boost on this engine?

    I've read a few guides on rebuilding the head, and I have a Bentley manual, but I'm no pro. Is this something that I could realistically do in my garage, with someone else's help? I've got proper tools available and space to work.

    I'd appreciate any advice and input that you folks could offer.

    #2
    you don't have to pull the head to replace the rocker. I did it on the intake valve of cylinder number 1 with the timing belt still on the car.

    You remove the valve cover and look at which rockers engage as the camshaft turns. Then you pull the clips off the rockers and move the intake/exhaust rocker of one cylinder to the opposite side so when you turn the engine and it 'comes on cam' those rockers are not engaged. Then as that cylinder comes 'on cam' you slide the rockers from the next cylinder over and so on. Ultimately you will find a point where none of the remaining rockers are engaged. This takes the moment force off of the rocker shaft so it can slide forward. You will have to take the cam gear bolt off and remove the plastic cam gear cover and the rubber things in the head before you can slide the shaft forward. Then you can slide the shaft through the cam gear sprocket to replace the broken one. I would leave the timing belt on so you dont mess anything up.

    You could do it in your garage, but of course by not removeing the head you dont have to replace headbolt/ cam/ headgasket like you may want to.

    Originally posted by downforce22 View Post
    Not true. :ohsnap:
    I just replaced #1 rocker on intake by sliding the rocker shaft out front toward the radiator removing all 6 rockers to get to number 1. I replaced a couple worn ones on cylinders 5 and 4 in the process.

    You can remove the radiator and should be able to move the engine around to get the shaft out. I also did it with the timing gear and belt on, just removed the plastic cover on the timing gear. This was on a 325iX so the motor mounts may be slightly different placement but the principal is the same. It took me an afternoon. I would suggest going to a junkyard and getting a spare head if you can for cheap so you know how the rocker/clips/rocker shafts go together and practicing removing the rockers on the junk head before doing it on yours.

    Here is a simple DIY http://e30technic.com/forum/showthre...adjustment-DIY

    I would suggest a few things.

    -If you have the timing belt on you can turn the cam without damaging anything. This allows you to remove the rocker retaining clips and slide them off the cam which lessens the force on the rocker shaft allowing you to pull/slide it out easier.
    -Be careful not to mushroom the shaft as you tap it out of place. I used a quarter inch drive extension, it worked great.
    -While you have the fan off and finish the rocker do the valve adjustment as you can turn the cam with the crank without moving the car/lifting the car.
    -The most annoying thing was having to drain some of the coolant hoses/radiator and fit it back together with coolant dripping on you. I didn't drain the block of coolant and suggest you don't either.

    It seems intimidating, just be careful and pay attention and your vert will be running smoothly once again.

    And as for your question above, no the rocker breaks and the spring returns the valve to closed position. The rocker is therefore a fail-safe that protects the engine from further damage. The rockers were designed to break where they do to protect the engine from damaging itself.
    Last edited by downforce22; 08-08-2016, 10:41 AM.
    318iS Track Rat :nice: www.drive4corners.com
    '86 325iX 3.1 Stroker Turbo '86 S38B36 325

    No one makes this car anymore. The government won't allow them, normal people won't buy them. So it's up to us: the freaks, the weirdos, the informed. To buy them, to appreciate them, and most importantly, to drive them.

    Comment


      #3
      Originally posted by downforce22 View Post
      you don't have to pull the head to replace the rocker. I did it on the intake valve of cylinder number 1 with the timing belt still on the car.

      You could do it in your garage
      I feel like I'd have to pull the whole front clip off to do that, though - although maybe this is a chance to refurbish my kidneys and grille!

      Edit:
      Just saw your edit. This might very well be the route I'll go - I could hold off on rebuilding the head until I have a more steady financial footing.

      I might do this and then later get a used head, get it machined, and rebuild it.
      Last edited by mleonardo; 08-08-2016, 10:46 AM.

      Comment


        #4
        You just have to remove the front timing cover, fan, and I had to remove the radiator to get the shaft far enough forward. You would have to remove this stuff anyway to remove the head... Its way better than pulling the head.

        Heres some pictures to give you an idea.

        http://www.e30zone.net/e30zonewiki/i..._Cylinder_Head
        318iS Track Rat :nice: www.drive4corners.com
        '86 325iX 3.1 Stroker Turbo '86 S38B36 325

        No one makes this car anymore. The government won't allow them, normal people won't buy them. So it's up to us: the freaks, the weirdos, the informed. To buy them, to appreciate them, and most importantly, to drive them.

        Comment


          #5
          Thanks for that link! Besides the rocker arm, what other hardware did you replace?

          Comment


            #6
            Nothing, I just did a valve adjustment at the same time
            318iS Track Rat :nice: www.drive4corners.com
            '86 325iX 3.1 Stroker Turbo '86 S38B36 325

            No one makes this car anymore. The government won't allow them, normal people won't buy them. So it's up to us: the freaks, the weirdos, the informed. To buy them, to appreciate them, and most importantly, to drive them.

            Comment


              #7
              Were you at redline when the rocker broke, or were they way out of adjustment?

              'Cause usually on raceycars it's the intakes that go from valve float.

              +1 on leaving the head on, though, if you're not ready to dive in with both flaps of your wallet. It's not so hard...

              t
              now, sometimes I just mess with people. It's more entertaining that way. george graves

              Comment


                #8
                Originally posted by TobyB View Post
                Were you at redline when the rocker broke, or were they way out of adjustment?

                'Cause usually on raceycars it's the intakes that go from valve float.

                +1 on leaving the head on, though, if you're not ready to dive in with both flaps of your wallet. It's not so hard...

                t
                Waay out of adjustment, I've been at my 7k redline numerous times before on stock rockers and nothing's broke - I didn't know that they liked to go on M20s.

                Comment


                  #9
                  Yeah, they don't like the slapping of being loose <heh>
                  and you're right-
                  the M20 seems to be particularly sensitive to that....

                  (6500 on a stock M20, btw)

                  t
                  now, sometimes I just mess with people. It's more entertaining that way. george graves

                  Comment


                    #10
                    Originally posted by TobyB View Post
                    Yeah, they don't like the slapping of being loose <heh>
                    and you're right-
                    the M20 seems to be particularly sensitive to that....

                    (6500 on a stock M20, btw)

                    t
                    7k with the eBay tune I use haha

                    Comment


                      #11
                      Originally posted by downforce22 View Post
                      You just have to remove the front timing cover, fan, and I had to remove the radiator to get the shaft far enough forward. You would have to remove this stuff anyway to remove the head... Its way better than pulling the head.

                      Heres some pictures to give you an idea.

                      http://www.e30zone.net/e30zonewiki/i..._Cylinder_Head
                      I'm having trouble getting the front timing cover off, specifically, the bolt that holds the alternator bracket on. I don't have the proper tools to undo the fan - is that going to stop me? Should I power through and get the fan off?

                      Comment


                        #12
                        https://dl2.pushbulletusercontent.co..._181437082.jpg

                        The pulley is solid; I can't get a rocker arm through there. Do I need to pull the head?

                        Comment


                          #13
                          I got my pulley issue solved, but how the heck do I push the rocker shafts out the front? I've ensured that there's no moment force on the exhaust shaft (all the rockers are off cam), now how do I get the shaft out?

                          Comment


                            #14
                            Did you remove the plate at the front of the head that locks the shafts in position? If all rockers slide side to side easily, then the only thing holding the rocker shaft in is varnish/sludge that builds up on exposed areas. You might have to try to clean that stuff off. Can you rotate the shaft?

                            Comment


                              #15
                              The rocker shafts may also have been mangled by a previous owner, so they no longer fit through the bores in the head.

                              Comment

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