All of this has had me studying up on the rating system last couple of days, long over due and can thank the forum for bringing me to that. As a result, I'm changing from a 229.5 oil to a 229.1 in my 87 190D Turbo and staying with that spec in the M110. The 228.3 oils I found were SM oils or CJ-4 for cat equipped vehicles, but the Liqui Moly 10w-40 MOS2 seems like the best bet. Total and Liqui-Moly have older formulations (VDS is a good early full zinc cert from Volvo). However I may end up with SWEPCO 306 and some 502 together. Brad Penn is my possible other choice but it's a race/"hot rod" oil and those owners like to change their oil when they feel like and that can be a lot. The LM 10w-40 MoS2 has done well in my 73 M110 engine too. With that oil and all things being healthy, my M110 gets smoother and smoother, including the valve train which I know is well adjusted. Ferrari and Porsche dealerships use SWEPCO 502 as it helps with valve train noise and dry starts, something that sounds good for my boat motor and maybe the horizontal shaft Coleman gen. I'm due for an oil change in my OM602A and still watching my M110 oil slowly get dirtier, but am quite comfortable with the Liqui-Moly 10w-40 MoS2, Schaeffer Oil makes a strong zinc oil but SWEPCO has the older CI/SL specs for 15W-40 much like Liqui-Moly. I did learn a lot from the Porsche community on line, it's easy to tell the hands on rich guy forums from the armchair ones, but those motors eat zinc and they're all afraid of any oil that isn't modern and full of zinc.

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87 190D 2.5 Turbo
73 280 base
69 Seafarer 31-1
Sold----
93 300E 2.8
92 190E 2.3
85 500SEC
71 220b
73 280SE 4.5