Re: Oil advise for 2.3L omc.
I understand SA/ Non detergent, I know their recommendation is not to use after 1930, it's more than a few years shy of when it was last used tho. ND was common into the early 60's, Detergent oil wasn't common until the 50's, and even Chevy's first V8 came without a filter ( actually optional ). The theory was/ is. the trash, would fall to the pan and get caught in the sludge. The oil pan could be pulled periodically and scraped clean.. It wasn't ideal for the trash to get pulled thru the engine without getting filtered, but also Detergents were still uncommon when many of these engines were made. If I had an engine without a filter, I would also add 1 and then run detergent oil, but not without first checking the sludge condition in the engine. Detergent could dislodge sludge and plug up a galley, and wipe out bearings.. My '51 Chevy ( yes, An automobile ) has had a filter since it was new, specs SAE 30 for the warmer climates so I run Shell Rotella T1 SAE 30, as it's a good high quality detergent oil. It specs SAE 20 for year round climate, but I haven't found it in a detergent oil, it's a fair weather car anyway.
If I had an engine that was newly rebuilt but couldn't take an oil filter because there were no provisions, I would run a detergent oil.. I can add that aside from my air compressors. I'v never had a need for API SA oil.. Pretty much the only need for SA is if the engine has sludge which could be dislodged by detergents, but many of those engines are still in service
I'v also had a Beetle. Key point had. because those 1k mile oil changes and other maint costs were eating me alive. All I wanted was a cool DD
The OP's 2.3L has a good full flow, full pressure oil, so he too should be running a good detergent oil in the weight that OMC published