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Valve Adjustment

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  • Valve Adjustment

    Seeing as it was my idea to get this DIY section going I may as well be first to post!

    Recently I did a valve shim adjustment as part of some regular maintenance. It was my first crack at it and was easier than I thought.

    So here is a quick rundown of a valve job on the s14. Its actually a gap check for the shims..

    Said shims: These little guys are quite pricey (I know they can be had cheaper!) and come in different thicknesses, in gradations of .05mm.

    They sit below the cam and must be checked periodically to ensure the clearance between the lobe of the cam and the shim/bucket is within spec. BMW S14 spec is 0.28mm-0.33mm COLD and of course only do this procedure when the engine is dead cold.

    Obviously you have to remove the valve cover and the spark plugs first. Very straightforward - 10mm socket is all it takes. it may be helpful to remove the fan and lower airbox assembly so you can put a 36mm socket on the crank bolt for engine rotation.
    Then, using a 36mm socket rotate the engine till the point of the first set of cam lobes are 90 degrees to the shims like so..

    Then, using a feeler gauge note the width of the gap. (I used one with angled tips which made getting the feeler gauge in position very easy). You will need to write all this info down so take your time and do it right. Continue doing this for all 16 shims, always rotating the engine to place the lobes up prior to measuring. Remove the out of spec shims and measure them, recording their width. Then put them back in place prior to rotating the engine for the next measurement. With that done a little math must be used to figure out the required shim width (if out of spec).

    Its pretty simple..
    Add the measured valve gap to the measured shim thickness and subtract the desired valve gap to get the new shim thickness. For example, if a valve gap measured 0.38mm, and the shim measured 3.6mm, and the desired gap was 0.28mm (any value between .28-.33mm is okay), the new shim would measure: 0.38 + 3.6 - 0.28 = 3.70mm. Thus, the new shim would need to be 3.70mm thick. Simple isn't it?

    You can see the shims and the rings here..note the lobes are pointy end up..

    A special tool is needed to remove the shims and you can see it here (Skyway Tools #1007 Double Ended Tappet Depressor) .. What it does is push down on the rings that hold the shim in place, allowing the shim to be removed. There are two ends to the tool. The wider one is for the intake cam, the narrower one for the exhaust cam. Here it is in position..

    and all the way down..

    Before placing the tool in position, rotate the rings so the indents are off to the side..

    When you place your tool and press down the rings will rotate towards it, like so..

    What you've done is made it easier to place your air nozzle in that ring gap and using compressed air blow the shim free. (There may be some oil in the recesses - place a rag or syphon it out so it doesn't spray everywhere!)

    Use a magnet to grab the shim (not shown)

    Once you've gone thru the entire set of shims and done your math you can then order the required shims, noting that you may be able to move some around to meet your gap requirements. Its very important that you actually measure the thickness of the shim and not just rely on the value printed on it..

    When you get your new shims, double check their thicknesses and install them where required following the guidelines above.

    Clean your gasket surfaces thoroughly, put your valve cover back on and connect the vent hose, double check your oil and your good to go!

  • #2
    Thanks for doing this, great pictures.


    • #3
      Nice!! Well done!


      • #4
        Great post, many thanks!

        1989 E30 M3 Zinno
        2004 330i ZHP (sold)
        2018 JCW Mini


        • #5
          Edit - Second photo lobes are 180 degrees to the shim/valve bucket, not 90 degrees.


          • #6
            Originally posted by JimK View Post
            Edit - Second photo lobes are 180 degrees to the shim/valve bucket, not 90 degrees.
            Thanks - the picture is right my geometry was wrong.. Good catch - wish I could edit my post... aarrgg...


            • #7
              Thanks for detailed pics, sometimes people forget to show as much as they can.
              I found the same tool after much searching on pelicanparts of all places. I believe theirs is the "sirtool" variation:

              Tappet Depressor, BMW, For All M Models Except European Cars, Each Bmw Service tool# 11 3 170 Part #: TOL-3012

              Side note, it looks as if you have the stock cams as do I. I had so much trouble rotating the cams just the right amount when re-installing them because they don't have flat spots for a wrench!
              I got lucky with screwdriver against the front cog nuts combined with the tappet depressor and a few other tricks. Does anyone know if the sirtool engine turning bar is meant to rotate these suckers? It would make life a lot easier with the stock cams:



              • #8
                Man that looks great! Thanks

                Disclaimer: Remember, I know absolutely nothing, but it doesn't prevent me from having an opinion or suggestion. :


                • #9
                  Nice write-up. Thanks.

                  One thing I always have to remind myself is to put the car in neutral before starting the procedure. Or you'll be moving the car while turning the engine!


                  • #10
                    Excellent point!


                    • #11
                      Took the numbers down today to see where they are.

                      My feeler gauge set jumps up a bit so it was hard to get an exact but I used the following sequential gauges:
                      .254 / .279 / .305 / .330 / .356

                      So anything between those values would either force me to move up or down a gauge to get it to fit in so it can end up a bit Tight or Loose with that largest possible gauge.

                      Here are the current gaps - anything stick out? (as pointed out .280 - .330 is spec)

                      Cyl 1
                      Intake: .330 (tight) / .279
                      Exuast: .305 (tight) / .305 (loose)

                      Cyl 2
                      Intake: .279 (tight) / .279 (tight)
                      Exhaust: .305 / .279

                      Cyl 3
                      Intake: .330 (loose) / .279
                      Exhaust: .330 (tight) / .305

                      Cyl 4
                      Intake: .254 (loose) / .254 (loose)
                      Exhaust: .330 (loose) / .330 (loose)

                      So what jumps out at me is the .254 gaps on cyl 4 intake...
                      Given it was loose so in reality it could have been closer to .265 or .270 (I couldn't fit the next size up .279 feeler in)

                      The exhaust are on the tail end of spec for cyl 4 so perhaps I should just.. swap them with each other? Thoughts?

                      Wish my feeler gauges had more options.


                      • #12
                        Excellent topic and very well illustrated, just wondering if anyone has kept a record of there gaps and noted if the shim clearance increases or decreases with normal street driven cars.
                        The reason I ask is this winter months I will adjust the valves for the first time since engine O/H back in 2011, I kept a record of the p/n, shim thickness and clearance of all the valve positions on a spreadsheet.

                        I have noticed I have 5 shims at 3.60mm with 9 clearance and 6 shims at 3.65mm and 9-10 clearance, what are the chances they have tightened or loosened enough to reuse most of them or will they be all over the place with different clearance. My M3 is quite hot or cold with no tapping noise from loose valve clearance.

                        E30 M3 1987
                        Mini Clubman GT
                        BMW E36 323 Msport
                        Toyota Corona
                        KTM 200EXC
                        Honda CB50 (1979)


                        • #13
                          thanks for the info. looks like the pictures are no longer available.