QuestionI have a 1976 mg midget, getting ready to chnage the oil, last time I went by what to book said and that was 20w 50,,,, do you think I should go with this weight oil ? Or do you recomend something else ?
AnswerHi Steve It is vital that you do not use a modern (thin) oil such as 10W40 or 5W/30, because:
1) You will have problems with low oil pressure.
2) Modern oils contain high levels of detergent, so they will strip your engine of any beneficial deposits which have built up, causing your engine to start leaking oil.
3) There is a problem with ZDDP levels. ZDDP contains Zinc and Phosphorus.
Modern oils contain very little ZDDP because the Phosphorus damages catalytic converters.
Your engine is an old design with flat cam followers. These quickly wear out unless the oil contains sufficient ZDDP.
I recommend that you stick with 20W/50, and check which brand has the highest level of ZDDP.
Valvoline VR1 is one of the best, with 0.13% ZDDP (most oils have 0.05% or less).
