BMW M5 Forum and M6 Forums banner

1 - 2 of 2 Posts

14 Posts
Discussion Starter #1
Now that the E34 has reached the 25-year import threshold, I wanted to share my experience performing a valve adjustment on the Euro market-only S38B38 – there’s more than a handful of things that are different than the previous generations of S38 engines, not to mention a bunch of conflicting info in different forums. Hopefully I can make clear the first and not add to the second, but all suggestions for improvements for this writeup are welcome.

First, there’s a scan of the E34 repair manual floating around that recommends the first step is to remove the cowl and fan so you can rotate the engine crank. Don’t bother. Apparently unlike prior S38s there is no large nut on the end of the crankshaft at the vibration damper, instead there are four smaller bolts. Nothing that would help you rotate the engine. I went down a bit of a rabbit hole leading up to this one, as the 32mm wrench I’ve used on my M30 engines was too fat to fit between the fan and engine, so I spent a week looking for a thin 32mm wrench specifically designed for removing the fan clutch. Only to find it didn’t help. Argh. I wound up bumping the key, which isn’t ideal as I needed to strip off dirty coveralls and gloves each time I wanted to rotate the engine so I wouldn’t track grease into the cabin. If anyone knows if the starter crank signal can be accessed at the diagnostic port I’d be massively appreciative.

Next, I went searching for the valve tappet tool, BMW special tool 113170. I started searching Sir tools and Samstag for that part number, but found a note “applicable for all BMW M engines, excluding Euro models.” Since the S38B38 was European market only and never officially came to the US, that sent me down a second rabbit hole searching for 113150. After all, I wouldn’t want to order a USA tool when I have a Euro-only engine, right? I found a site that had both tools, at the best pricing, and as a bonus the Euro version was cheaper than the USA model. That alone should have told me there something was wrong, but I pulled the trigger anyway and ordered the Euro version. Of course, the oldtimers reading this are groaning and slapping their foreheads as the 113150 tool is only for the M88 engine, used on the M1, Euro E24 M635CSi and Euro E28 M5. Back to to order the 113170. I kept the original 113150 both because, well, you never know. Life goals.

Also, on the E34 the tool doesn’t clear the AC line when trying to adjust cylinders #5 and 6. I followed the directions 11 34 004 of the BMW repair manual to remove the plastic cover, clip the wire ties, remove the metal holder and press wire harness aside, but it still wasn’t enough clearance. Ultimately it was easiest to cut the tool into two – you don’t need the additional length for leverage, and it was almost easier to have separate A Exhaust and E Intake tools. A grinder and cutting wheel made short work of the task.

I also needed to find a source for the valve shims. It’s theoretically possible to take all the measurements, order individual shims and then replace them all, but that would mean multiple teardowns or having the engine sit open for at least a week while parts are ordered, which was not ideal. Multiple posts on the forums indicate Volvo shims will work at a fraction of the price, but may not be an identical match – apparently BMW machines a small radius on theirs? In any case I wanted to do this right, and for me the cost of parts is a relatively small part of the equation. I figure my time in doing this work is the real cost savings of owning a classic and I really enjoy the zen of working on my own vehicles. That being said, quotes for BMW’s 11349061386 valve shim kit from all my normal sources were crazy stupid expensive. I wound up getting a kit from Schmiedmann, as they were only crazy expensive and I had to get some other Euro-only parts so could combine shipping. Consider it an investment.

Finally, I hate doing math. Most of doing a valve adjustment is measuring the valve clearance as it exists, pulling and measuring the shims for every valve that is out of adjustment (either too tight or too loose) and adding the two measurements and correcting to find the preferred shim replacement to achieve the desired clearance. To me, that’s exactly what a spreadsheet is designed to do. I found a handy valve shim adjustment calculator created by m3guru on, Valve adjustment calculator - - it covers both the S14 and S38 engines, and when you enter the measured clearance and current shim it pops out the desired replacement shim – including BMW part number! At first glance it’s pretty impressive, but after using it for my first pass I realized it had an error – it correctly calculates the max and minimum shim size needed, but then uses an MROUND function on the max thickness to round to the nearest 0.05. Since Excel can either round up or round down, sometimes the resulting recommendation would leave too little clearance. I revised the sheet BMW_s14-s38_valve_adjustment_updated.xlsx to find the average of the min and max thickness needed, then round to the nearest 0.05. This means the resulting net clearance should always be within the recommended range. I also rearranged the sheet and added some formatting to make it easier to read, as well as to count valves and cylinders from the front for consistency. Hopefully you find this sheet is helpful; any praise should go to m3guru for his work creating it and doing the heavy lifting, I’ve just tried to update and make it more useful.

So let’s get on with the valve adjustment, shall we?

The first step is to remove the valve cover cover. The S38B38 was BMW’s first M engine to use coil-on-plug spark, and the coils are under an aluminum shroud accessed by removing four cap nuts. Also remove the plastic cover along the side of the engine bay using a flat screwdriver to remove the two plastic cap nuts.


Next, unplug each coil pack by lift the metal lock upwards, then pulling gently on the plug.


Number each coil pack, to aid troubleshooting and so you can return it to the same position. The cables are marked with an embossed ring, but you can also tell them by length. Unbolt each coil and lift straight up to remove.


Using a 10mm socket, unbolt the two 6mm nuts holding the wire tray and then carefully remove the plug wire assembly, including the rubber boot that protects them down the side of the engine. I found I could fold this assembly back and set it in the windshield wiper area on the cowl.


Remove 18 cap nuts from around the valve cover, and six regular nuts that were under each coil.


Using a 5mm hex wrench, undo the two bolts that hold the crankcase vent assembly to the side of the valve cover.


Lift the valve cover straight off and set aside.

From here on out it’s just like any S38 valve adjustment, which if interested I can detail in a later installment.

74 Posts
Pin 11 should be the starter from the diagnostic port, it is that way on my 91 at least. There is a tool out there with a switch on it for this purpose but I have not been able to locate it online.
1 - 2 of 2 Posts