Factory specified oil grade is 10W-30 in the factory service manual for the 2002 Miata. Factory specified oil pressure at 3K rpm is 50 PSI. Lifters are bucket solids. Bypass is above 60 PSI. I have run M1 10W-30 EP with no issues but it caused the variable intake valve advance mechanism (engine oil activated) to behave irratically. The M1 0W-40 cured this behavior. The oil pressure gauge in the dash is a fake and only shows the oil is above the oil pressure switch turn on pressure of 10 PSI.
Someday I will install a real OPG.
Someday I will install a real OPG.
