Mehran's manual recommends 10/40 oil as minimum and 20/50 as Maximum.
But using LM oils in Mehran is not a good idea. Pretty much expensive for Mehran.
I'll suggest
PTT Performa 10/40
Kixx's G1 semi synthetic 10/40 (Fully synthetic is also available in 10/40, but using fully synthetic oil in Mehran is not good idea either).
SIM3 20/50 Semi synthetic.
ZIC M 15/40
The choice would be yours and according to the money you are willing to spend.