@syncview I have also in my last oil change switched to 10W40 API SN oil after flushing engine with STP. I plan to do at least 5K kms before I change it (the extended OCI is the reason to switch). Now I read from @xulfiqar that filter plays a very important role in long drain interval because a shoddy filter will stop working early and cause more damage so I bought the better than OEM VIC filter for my carby cultus 2001
While I respect your opinion but I think it would be unfair to generalize the experience of 4 cars with worn out cams to the usage of API SN oil. As you are aware most cars here in PAK are without thermostat / auto switch and also most people (I don't know where they learnt this) start the car in the morning (cold start) and rev it to red line 3 to 4 times and then just go about driving completely disregarding how to treat a car after a cold start.
Now a car which doesn't have the T-stat and auto switch (it will never reach optimum operating temperature) and which is filled with 20W50 (too thick in my opinion) and a gunky engine in which I am sure a thick oil will not travel as fast into all areas of the engine on a cold start and car which has never seen a PCV valve replacement how fast it will wear and tear and you also have to take into account the sale of fake oils. In my opinion more than 50% of branded oil sold are fake. Even petrol pumps carry fake oil. One has to be very choosy from where one sources their oil. I have read on PKwheels that even a company run website has supplied fake/sub standard oil to some users.
I have seen @xulfiqar to be the biggest proponent of running the engine on the ideal temperature in this forum, which is very delicately and precisely maintained with a tstat and auto switch and our mechanics love to throw away these two items out of any car they get their hands on. There is a reason to run the car on optimal temperature as the oilās detergent and wear and tear agents do not do their job on engines running on colder temperatures and only make gunk and jam oil galleries and stick on cams etc. This causes very high amount of high wear and tear. No matter which grade oil you put in this engine will not clock in a lot of miles before it will get noisy and start burning oil.
Also most cars are running on shoddy oil and air filters.
The whole point of mentioning the above is that you cannot draw any inference from your experiment even if the sample size is 40000 instead of 4 cars because to perform an experiment all above parameters need to be controlled before one can blame the oil. So until then I will want to believe what the API and all the theory says.
By the way I hope my CAM doesnāt fail but what would be the cost to replace the CAM in a carby cultus 2001?
