San Antonio valve adjustment

[davesz4mc]

The Basics

If you are doing a basic spec check and you are only looking to keep your valvetrain within spec here is the one rule you can work with.

If a .23mm intake or .33mm exhaust feeler guage will fit between the cam and the rocker replace the shim with one the same size.

Measure the shim you remove say it comes out to 2.23mm then you need to put a stock 2.24mm back in its place.

With the valve cover removed makes sure the valves you are checking are on the "base circle" of the camshaft, i.e. the lobe is pointing straight up(there should be two cylinders with valves on the base circle, for a total of 4 valves to check). Check your max spec feeler .23mm intake or .33mm exhaust, if it does not fit you are ok, if it does replace the shim. Lift the retaining clip for the rocker arms (easy with just fingers) and slide the rocker out of the assembly (easy with fingers). Use the special tool (recommended) to pick up the shim measure it and replace it (the special tool allows you to magnetically replace the shim and has extra material to allow you to drag the magnet off the shim and still keep it pressed into place) and lift rocker with fingers and slid it back into place, replace retaining clip. Now check spec again see it is corrected and finish all the valves the same way.

If you have a shim set on hand and you are doing a basic adjustment you can be done inside 4 hours, faster the second time.

TIP: if you put the car in reverse no brake you can bump the car backwards to spin the valvetrain (the correct forward rotation) to get the next pair of valves on the base circle (do not bump car backwards in first gear! this in counter rotation and is advised against)...

[BMW Maniac]

I can't wait to see this....I really would like to do this on my own instead of paying for it at an independent shop.

[davesz4mc]

OK so I did my valve adjustment this Saturday I will go into more detail though I am disapointed in the results... Sorry I was unable to document with photos and video family issues I had to complete this as fast as possible so focused on just doing it right...

So the shims are in mm and an example size is 2.24mm next size up 2.28, 2.32 and 2.36 etc in steps of .04mm. I feel there should be a performance shop out there making a shim kit with half steps on the stock kit like 2.24, 2.26, 2.28 with a .02mm step.

So this is how I worked out all shim jobs should go reguardless of the particular s54 engine. Yes I replaced all 24 shims in my engine why? because I wanted to eliminate all wear reguarless of wether it was in spec.

I first started by using a max spec feeler guage .23mm intake .33mm exhaust, If it was under max spec (does not fit) I just replaced the shim in it with a new shim of original size. If it was barley max spec (had to work it in) all you can do it replace with stock size or the steps are too large and you will be under min spec (a half step would be perfect for these shims). If it is a loose max spec you can step up to the next shim size and still meet min spec of .18 intake or .28 exhaust.

There is a huge improvment in feel and noise levels after doing this and it was super easy (trick to rotate the cam is put the car in reverse and bump it backwards to turn the motor and rotate the next valves). I would recomend this to anyone with a little bit of patience and a willingness to DIY.

When I do this again or get a customer into the shop that needs it done and wants to help we will document it.

Feel free to ask me questions as I have a really good understanding of how this all works now...

[davesz4mc]

bump, I updated initial post with the basics for DIY...