Originally Posted by Iamreal
What's the purpose of valve adjustment? I'm about to do my maintainence and I plan on doing belts, diff, transmission, spark plugs, brake flush, air and cabin filter. Is that enough?
First, congratulations on the purchase! Second, if you can do those things above, you should be able to do the valves. Several DIYs can be found here if you search. It's not that difficult. Second, here is a great link
on step-by-step DIYs (not the only one, there are many available for the S54). Here's another
. Or use Search, and look for "Valve" in the title and have results shown as thread.
"Why?" Because the S54 uses shims to set the amount of lift for valves. Over time, shims wear, as other parts of the valve train. This means the valves may not open optimally (loss of power) or close properly (worst case, "burned valve" which you don't want to have). It's a high-performance engine, and needs this adjustment done every 15K - 28K miles (depending on use). The car keeps general track of use based on amount of gasoline used, and will note when the next inspection is due. If you don't know the history of the car, I'd advise doing the valves. Worst case, you'll find little to adjust, best case you will have saved yourself a big headache.