The crux of the argument really stems from this mysterious compound called ZDDP (Zinc dialyldithiophosphate). In a nutshell, ZDDP protects the internals in our flat tappet engines and modern oils lack it.
As far as BMWs are concerned, I used to use BMW conventional 20w50 (SG/SH) rated when it was blended by Spectro, then I switched to Liqui Moly Racing 4T, and then back to BMW as a result of Kurt from the BMWMOA's excellent Oil Analysis Project. While Airhead gurus recommend Golden Spectro 20w50, the test results actually showed that BMW and Spectro 4 were excellent conventionals (no surprise since they were blended by the same company) concerning ZDDP levels, and Mobil 1 V-Twin and Redline topped the synthetic list, Golden Spectro was actually fairly consistent with the conventional Spectro oils which was disappointing considering it's semi-synthetic. All this being said, every oil tested met minimum BMW specs and unless you are extremely anal, like most BMW owners, any oil would get the job done.
Since the testing was done back in 2012, BMW has dropped Spectro as a blender for BP/Castrol, and Porsche has come out with their own "Classic Motor Oil," intentionally designed for old, flat tappet boxers. This is unique because all of the oils tested in Kurt's run were one-size-fits-all concerning motorcycle use. The BMW bottle (when it was Spectro and even now) says it's OK for "all" R-bikes - a very bold statement given the various engine configurations over the years. So who cares?
Well, back when Kurt got his test results, Castrol 4T SG rated conventional was on the lower end (but still meeting BMW specs) of the spectrum concerning ZDDP, although quite good concerning TBN and viscosity. Coincidentally, when BMW changed from Spectro to Castrol oil, the API rating went from SG/SH to just straight SG which matches the Castrol 4T rating. The question concerning this oil is whether or not the new BMW oil is a unique formulation or just a rebadge of Castrol 4T; if found to be the latter then it could save people some money since Castrol is about half the price of BMW oil. But what about the Porsche oil?
Porsche oil tells you nothing about it except that it's designed for old engines. You won't find any API rating and as far as I can tell, no ZDDP levels. It also seems that no one has yet had this oil analyzed (based on extensive google searches), so there are no proof for BMW (or Porsche for that matter) owners that this oil is any good other than Porsche's word. If their word is good, and since this oil is priced similarly to BMW's oil, this may prove to be an attractive oil to use for our old classic boxers.
So let the analysis begin.
Kurt used Bently Tribology (now Cashman Fluid Analysis) back in 2012 for his Oil Analysis project. I opted to use the same labs, with the same equipment, so my test results could be directly comparable to his. The cost was exactly the same as Blackstone Labs, and like Blackstone, their services include a free kit that they mail you.
Here's the two oils being analyzed.
And here's the sample kit.
Pouring out the oils into the kit revealed quite different appearances, but what this means I really don't know.
When Kurt had his testing done it took about 2-weeks to get results. As I sent mine out today, I should be expecting results sometime around 10 October. Will update with the results on here and the BMWMOA once they come in.
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