Looking at a 1988 Marine Trader 36 with twin SP90's and was curious as to the oil required...
I have a Lehman Power Owners manual for the SP90 dated June 1987 and it specifies on page A24 that for my operating temp (32ºF to 90ºF) to use 20W/20 API Spec CC
I also have a Operator Handbook (Edition 8) for Ford 2720 Range 4 & 6 Cylinder Diesel Engines (including the 2722 4Cyl 254cu in SP90) and this is dated November 1988. This handbook specifies API Spec SF/CD Multi-Viscosity 10W-30 or 10W-40.
Anyone have any insight to the discrepancy between the two documents and the straight weight oil vs. the multi-viscosity oil?
I have a Lehman Power Owners manual for the SP90 dated June 1987 and it specifies on page A24 that for my operating temp (32ºF to 90ºF) to use 20W/20 API Spec CC
I also have a Operator Handbook (Edition 8) for Ford 2720 Range 4 & 6 Cylinder Diesel Engines (including the 2722 4Cyl 254cu in SP90) and this is dated November 1988. This handbook specifies API Spec SF/CD Multi-Viscosity 10W-30 or 10W-40.
Anyone have any insight to the discrepancy between the two documents and the straight weight oil vs. the multi-viscosity oil?