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Need advice from experience for an M42 rebuild

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    #61
    Need advice from experience for an M42 rebuild

    my neighbor has a hoist with a load lever that we can use. so i'll get to work on disconnect drive shaft and other sensors and hoses and such.

    my main concern is do i need to disconnect any a/c components prior to lifting it out? if so i read that it's illegal to do this yourself, so since the car is not able to running in its current state, do i have to tow it to/from a shop just for this step?

    Last edited by JonsE30; 06-23-2019, 04:21 PM.

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      #62
      You can leave the compressor or compressor+bracket hanging in the engine bay. Clearly you should try to support it as best you can.

      If you really wanted to evacuate the system you can do that without the car being operable, so long as you can get/borrow the equipment, and yes, it is illegal to vent refrigerant to atmosphere intentionally.

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        #63
        You mean I would be able to unbolt the a/c compressor from the block without having to mess with any of the a/c lines and support it so it’s not just dangling?

        I’d rather do that if it’s not too difficult so I don’t have to tow it to a shop just for the evacuation.

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          #64
          Yes, unbolt it and leave it in the bay. Depending on the angle of the engine extraction you may have to hold it aside.

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            #65
            i'll give that a shot. thank you all so much for the guidance!

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              #66
              Worked like a charm! Took the 4 13mm bolts out the top left one was hard to get leverage but finally broke them free. Next i gotta tackle the guibo bolts, then pull the ecu and wiring through the firewall, and i think i should be ready to pull block and transmission out!

              Slowly (very) but surely....

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                #67
                Originally posted by JonsE30 View Post
                Worked like a charm! Took the 4 13mm bolts out the top left one was hard to get leverage but finally broke them free. Next i gotta tackle the guibo bolts, then pull the ecu and wiring through the firewall, and i think i should be ready to pull block and transmission out!

                Slowly (very) but surely....
                I found it easier to fold the wiring up on the windshield after removing the intakes. It gave me really good access to the rear lift point on the block for the cherry picker.


                1991 BMW 318i Alpinweiß II Slicktop 231,000 Miles Build date: Wednesday, 1/30/1991
                2003 BMW Z4 2.5i Sterlinggrau Metallic 112,000 Miles Build Date: Monday 12/9/2002

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                  #68
                  I finally got everything disconnected minus the motor and trans mounts.

                  Since I’ve never done this before and don’t wanna mess up catastrophically I wanted to check again:

                  With the head off, I put the head bolts back on to thread the chain through. Which head bolts are the best lifting points? Any other area besides the head bolt I should try to lift from?

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                    #69
                    Only other great point would be the cast ear near where the starter would be. Consider the angle you will want to achieve duing the pull, and let that dictate your lift points. Remember that two lift points too near each other will make the engine harder to control coming out.

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                      #70
                      i'll keep that in mind this weekend when i pull it out. i called my shop and they can't get to work on my block for 2 months, so i gotta drop it off and work on other parts of the car, maybe clean up the engine bay during that time.

                      the shop mentioned i have to strip the block before dropping it off. it looks like i have to remove all the electrical, alternator, water pump, the timing components in the car, mounting arms.

                      i think he said i can leave the oil pump and pan on, but it looks like the oil pump is mounted to the side of the timing case.

                      is there a proper sequence, did i miss anything?

                      thanks in advance

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                        #71
                        The oil pump is integrated into the timing case, so if the shop wants the case removed, the oil pump is included there. It is a good idea to check the condition of the rotors anyway, and pack them with assembly lube to avoid pump priming on the first start. You can also check the condition of the oil pressure relief valve bits in the bottom of the timing case.

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                          #72
                          Mini update: I had an hour before the wife and kids got home and removed the electrical from the engine. I tried to document and label as much as I can.











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                            #73
                            Motor is out! With the help of a good friend and my neighbor we got this nugget out. It would have been straightforward but of course I forgot something that was holding it in there. Once we got it out I started removing all the accessories and the transmission to prepare it for drop off at the machine shop....i feel so accomplished! Haha.

                            Things discovered:

                            One of the mounting arms of the starter that mounts to the transmission was precisely broken and was attempted to be repaired but it cracked off.

                            I didn’t know how to take off the lower timing cover. I got as far as removing that piece in front of it, but when I got the front piece off I did it know how to remove that piece that looks like it has 2 gears that is over the crank bolt. So I just removed the chain guides and chain and put the cover back on then that long bolt on for the pulley. It looked like there was a notch for it to go back only one way.




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                              #74
                              Need advice from experience for an M42 rebuild

                              So luckily i called the shop and they said i can leave the oil pan and lower timing cover on when i drop it off however, i know i am going to have to deal with that eventually when i replace the timing components and the timing cover gaskets.

                              when i take off the crank bolt, i can remove the front lower timing case cover to see all the timing gears, chain and guides. there is an allen bolt for the sprocket on the top , but how do i remove the sprocket (the one that looks like a double gear) at the bottom where the crank bolt is? it looks like this needs to be removed before i can unbolt the inner timing case cover from the block, i dont see a bolt or anything, does it just slide off?

                              Last edited by JonsE30; 07-01-2019, 08:47 AM.

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                                #75
                                Yeah, #8 just slides on/off. Part #9 indexes the angular position of both #8 & #6 (and crucially, #1). The immense clamping force from the crank bolt (#4) is what allows all of the torque to be transmitted from the crank to the timing sprocket and the damper/main pulley.

                                IMO the crank bolt is harder to loosen with the engine out of the car since it is not bolted down, but a decent impact gun should do the trick. I made a crank locking tool which bolts to the #6 hub, but it sort of relies on the car's frame rails to lock against. Getting the bolt back in with the correct torque can be done once the engine is back in, and I can mail you the tool if you need it (looks like USPS is ~$22 each way from here to SoCal).

                                Also, most torque wrenches do not go up to 224 ft-lbs, and I use a pull force gauge on a breaker bar + pipe at a measured distance to get the proper effective torque.

                                Lastly, give part #1 a good, close inspection. It comes off easily by removing the 6 x #3 bolts. This is the SINGLE most important part for running the engine since that toothed pattern is how the ECU knows the crank angle & speed. These suckers are all about 30 years old now and the rubber on many is cracking and allowing major wobble of the outer metal toothed part. New ones are almost $500 (ask me how I know lol), which hurts the wallet, but if yours is showing signs of physical failure then I highly recommend buying a new one. I suspect that these parts will become unavailable in the next couple of years. E36 M42 ones will probably be available a bit longer, but you would need to convert to a serpentine belt to use them.

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