[Thomas]

Yes, that makes sense. I am probably biased by modern considerations. And your english is fine. I appreciate that we don't need to communicate in mandarin... 

[klaudius]

With the single-range oil, the sludge should actually settle in the oil tank if there is no fine filter. The return pump must have it as light as possible. The machines were very different back then. Maintenance was not always observed, the reserves were generous. Forgive my English, please. Greetings Claudius

[Thomas]

Thanks a lot, Klaudius! That's surprising and I wonder why the mesh has such a large width. I mean, there is no filter effect at all, isn't it.
Cheers, Thomas

[klaudius]

The return strainer from the engine to the oil tank is intentionally kept coarse. I don't know your machine but if that's the fact it would be original. Greetings Klaudius

[Thomas]

The mesh width of my oil filter mesh seems to be very large and perhaps I need to make a new one. But what is the right mesh width?
Cheers, Thomas