No because the seals go out as well. From my understanding into their failure (other than the bolts) is that they have something like an anti drainback in there and the rattle is from them being dry at startup. From the replacements that I've done, it requires a few special tools to make sure the timing isn't messed up, clips, etc. The V8 (single and dual) VANOS are different than the I6 version. To be honest, I've never had to do an I6 one as of yet.

That wasn't my experience. My best mileage on the highway was 27 (imperial) on my 3.0, measured several times from fill up to fill up, and that was all on AKI 89. That suggests that in my case the timing was not being backed off, which would have increased fuel consumption. Engine started and ran great. All I got was the savings, not that it was enough to matter, only about $0.30-$0.40 per gallon. AKI 87 did cause a slight reduction in performance in my case.

It will be different for every owner, as fuel varies so much across North America. In some cases the local 91 is crap, and will still cause problems. Other locations have better fuel, and 89 is fine. Sweeping statements that owners must use 91 or 92 AKI or lose power just aren't true. Owners should use an AKI rating sufficient for the engine (but not higher).

I know how my 7 reacted the one time I did it, but as I mentioned, my engine I a little different than most.

My sweeping statement is based off what's written on the fuel door and/or the owners manuals in my cars. I do agree though that a cheap brands best gas could compare to a quality brands lowest grade gas. Maybe its just placebo for me, but I try to use the Top Tier brands on the BMW's and the bike, preferebly from a station that has in individual pumps for each grade so I don't fill up with however many gallon of 87 in the lines that the previous person used before me.

I wasn't aware that you put so much stock in BMW's recommendations :rofl:

Nothing wrong with Top Tier, but don't trust it to be more than it is. It doesn't cover quality in terms of either actual AKI, cleanliness, water content, or most additives. It only addresses deposit control additives, which is a very narrow spec.

Im selective in following their recommendations, some I follow with experience and others based on common sense.

BMW suggests (not demands) to use a quality higher octane gas, but that make sense with any performance tuned vehicle. I learned about the benefits of the proper octane when I supercharged my Tacoma as it pinged like crazy on lower octane gas but it stopped when I ran premium. My 7, while not FI, reacts the same way.

BMW demands (not suggests) to never change the transmission fluid, and in servicing situations to save the drained fluid and reuse it....that's just ignorant.

I take all of BMW demands and recommendations with a grain of salt.

Can any one else Say that keeping the oil maxed and changing to 0w40 has help with the start up knock?