Originally Posted by Alpina_B3_Lux
If you have the correct walnut shell blasting tool then it is actually quite simple from what I have heard. But if you don't, and you have to manually clean every valve from every cylinder with a toothbrush, then it certainly is a pig of a job and ideally needs at least two days (to let the valves soak in cleaning fluid before brushing them off).
I've ordered the BMW blasting tool and will hopefully be able to document how this is done in the next 2-3 weeks or so.
What is the BMW blasting tool? Do you have a PN? Where can I purchase?