A friend has an very old lister diesel motor ( runs maybe 50 hrs/year) driving a generator and uses an oil filter which fits an MGB sports car and it got me to wonder what is the difference, if any? between oil filter construction (regardless of the brand) for diesel engine oil vs petrol engine oil. I expect the oil grades/viscosity would generally be the same for either engine type but given diesel oil blackens up quickly with carbon is the diesel filter constructed differently to protect bearings etc due to a heavier filter need? Any thoughts?