At the engine mod. 406 the oil pump is driven by an intermediate shaft, for engine mod. 402 the pump and ignition distributor are driven by the camshaft
On engines mod. 406, filter 2101-1012005 is used, installed at the bottom of the cylinder block on the right side.
In order to replace the filter, you need to unscrew the old filter and screw in the new one.
Put a waste oil container under the crankcase
Unscrew the plug and drain the oil from the crankcase