kung mineral hanap mo madame yan viscosity.. starting from 10w40/1540/20w40/20w50 at kung anu anu pa...
just find a good mineral oil with ample additives inside and good base stocks...

viscosity wise walang epekto yan... but according sa bobistheoilguy forums, its better to use the lower starting number like 5w or 10w... all oils when at operating temp has the same viscosity.. ibig sabihin kahit 10w30,5w30,10w40,15w50 lahat yan same viscosity pag operating temp na( pag mainit na makina)... what sets them apart is yung cold start rating(early morning starts)... mas mababang grade like 0w/5w/10w mas maganda para sa cold start flow where 80% of wear occurs... since gasoline engine ka naman 5w or 10w would suffice..