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Thread: 98 Z3 1.9 - Head Removal/Camshaft Timing Help

  1. #1
    Join Date
    Apr 2018
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    Birmingham, AL
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    1998 BMW Z3 Roadster 1.9

    98 Z3 1.9 - Head Removal/Camshaft Timing Help

    Hello! ’98 Z3 1.9 M44 –First post, long time reader, forum has helped me fix glove box, top leaks,coolant pipe replacement, radiator, waterpump, thermostat and more.

    Currently replacing ahead gasket, and need some input on the camshaft locking jig and possibly needingto adjust the camshaft (change timing) prior to removing the head. I’ve got theBentley manual, following Pelican parts tech articles and scoured this site.

    I’m replacing a headgasket due to overheating. I’ve got the intake manifold, valve cover, timingchain cover, etc removed. Bentley states that the camshafts should be locked atTDC before removing the timing chain (which is necessary to remove cylinderhead). Bentley doesn’t state that crankshaft should be locked first, butPelican and other sources do.

    So… the crankshaft hasbeen rotated so piston 1 is at TDC, the crankshaft locking pin inserted, andcrankshaft is locked in place. The cam lobes of #1 cylinder are pointed up anda bit inward towards each other. The square portions of both cams show the 2dots and are pointing upwards. The passenger side cam is straight up and downin relation to the engine (the 2 dots are at “the cam version of TDC”). However,the driver side cam is rotated very slightly towards the passenger side cam.Think of it as just a few degrees off center.

    I have a 2-piececamshaft locking jig with a metal clasp that can join them. The passenger side cam(don’t know if its exhaust or intake) has the jig installed correctly. It sitsfirmly on the square end piece of the passenger side cam and the jig is squareand flush with the cylinder head.

    Bentley/other sourcesstate that for correct timing, when the crankshaft is locked, that both camshaftjigs should be flush on the cylinder block. Only the passenger side is flush and themetal clasp cannot be joined. So, I’m thinking the timing is slightly off.

    The driver side lockingjig does not sit flush/square to the cylinder head. It is about ¼ inch up offthe right side of the cylinder head as you look towards the back of the enginebay. This is because the square part of the cam is rotated a few degreescounterclockwise, causing the locking jig to lift.

    In other words they look kind of like this = _ /

    Q 1). Does this indicatethe engine hasn’t been timed properly? It seemed to run fine prior to theoverheat. Can timing be slightly off and the engine still run fine?

    If I remove the lockingpin from the crankshaft, I could rotate the cams slightly with a wrench and getthe camshaft jigs on – however, now the crank pin wouldn’t be lined up, so I’mguessing that’s a problem. Not sure if I should do it this way, then remove head,then reset timing when reinstalling the head.

    Bentley says that correctcam timing is achieved when crankshaft is locked and both locking jigs areflush to the cylinder head. If not flush, it recommends adjusting cam byloosening bolts on camshaft sprocket.


    Q 2) should I loosen thosebolts and try and reset the cam? Would loosening the bolts on drivers side camshaftsprocket allow the driver’s side cam to move independently of the other cam?Then the timing could be set according to Bentley.

    Q3) am I overthinkingall this?

    Thanks for the help, I’mattempting to avoid damaged valves/pistons and trying to make sure things aredone correctly.

  2. #2
    Join Date
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    Q3 - Yes. You are going to disassemble the head so it can be milled and pressure tested. You time things on assembly.


    /.randy

  3. #3
    Join Date
    Apr 2018
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    Birmingham, AL
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    1998 BMW Z3 Roadster 1.9

    Thanks for quick response - clarifying

    Quote Originally Posted by rf900rkw View Post
    Q3 - Yes. You are going to disassemble the head so it can be milled and pressure tested. You time things on assembly.
    Ok, thanks - just to clarify.

    I'll remove crankshaft lock pin, rotate cams so jig fits flush to cylinder head on both sides (which may involve loosening, but not removing, bolts of camshaft sprocket on drivers side), follow Bentley and remove chain tensioner, locking bolt, 2 turns to adjustment sleeve, wire tie & remove camshaft sprockets, rotate engine 45% counterclockwise, then remove head.

    Insert crank pin on install and ensure timing is correct per Bentley.

    Once done, I'll come back to this page and update.

    Thanks!

  4. #4
    Join Date
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    Just take the head off. Your timing is wrong, no need to save it. You'll set the timing up on install.

  5. #5
    Join Date
    Oct 2012
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    1997 BMW Z3 1.9L 5MT
    Quote Originally Posted by Z3Sands View Post
    Hello! ’98 Z3 1.9 M44... Currently replacing ahead gasket, and need some input on the camshaft locking jig and possibly needingto adjust the camshaft (change timing) prior to removing the head...
    Here's a video replacing the head gasket:

    https://www.youtube.com/watch?v=JKg78rDfrIU
    BMW MOA 696, BMW CCA 1405

  6. #6
    Join Date
    Apr 2018
    Location
    Birmingham, AL
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    1998 BMW Z3 Roadster 1.9
    Thanks all - Cylinder head is safely out and out to the shop to get cleaned/tested milled.

    I went ahead and loosened the bolts to the camshaft sprocket on the drivers side, and adjusted the cam a bit with a wrench. I wanted to experiment a bit as this is my first time this deep in the engine, and knew I'd have to correct timing on install anyway. It was very easy to do. I put the cam locking jigs flush to head, removed the crankshaft locking pin, rotated the engine counterclockwise 45%, and pulled the head out with a friend. I did this with the portion of the exhaust attached to the head. Then, after head was out, removed exhaust. I'd soaked it with PB blaster several times - came off, no problem. I'll keep the post updated. Thanks again!

  7. #7
    Join Date
    Apr 2018
    Location
    Birmingham, AL
    Posts
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    My Cars
    1998 BMW Z3 Roadster 1.9
    Just a quick update - the head was pulled successfully/cleaned/machined, and new valve seals installed - which required removal of the cams. When I went to install and time the cams, I found that the machine shop had snapped the cam on the exhaust side. It only became evident when I turned the cam, installed the cam locking jigs, and found that the lobes weren't lining up properly - essentially only part of the cam moved. The cams are hollow and if not removed/or installed very carefully, they are easy to snap. For anyone doing this job, pay special attention! The shop located a used cam and will be installing and checking the intake side - should be ready in a day or so. Apparently a new cam isn't needed because the M44 1.9 has hydraulic lifters.

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