I assume that you were referring to the post in this thread:
Best engine oil for suzuki mehran?
These were the links posted:
Oils: Which motor oil should I use? Which oil is best for my Porsche or aircooled engine? <----this link is dead unfortunately
Zinc dithiophosphate - Wikipedia, the free encyclopedia
Motor Oil - Wikipedia, the free encyclopedia
Zddp In Motor Oil - Marina Alta Classic Car Club
For the first link, Porsche are meant to be performance engines with high lift/duration cams; I am not disputing the use of high ZDDP oil for them. However, I am not talking about Porsche's, Mustangs, Corvettes, and Baracuddas - Mehran, Cultus, old Civic and Corollas are more relevant here.
I am quoting the second link here:
"oils with reduced ZDDP have been cited as causing damage to, or failure of, classic/collector car flat tappet camshafts and lifters which undergo very high boundary layer pressures and/or shear forces at their contact faces"
This is what I am disputing; maybe our OHC engines with standard lift and duration don't undergo high pressures like classic/hot rod/racing OHV engines.
In the third link, under the API heading, the sequence IV test is mentioned, which is used for slider (flat tappet) cams.
In the second link in my original post, the IVa and IIIg tests are mentioned; the oils pass these tests for low lifter load engines, otherwise the starburst oils can't be advertised as backward compatible. Granted, the test isn't used for high lifter load engines, but we don't necessarily have those in Pakistan.
The fourth link mentions 500-1000 mile cam failures; I have never seen cams fail that early, but I am still young.
It also talks about modern oils as if they don't have any ZDDP. This is not true; they have a min of 600 ppm and a max of 800 ppm, compared to, say, SH oils with 1200-1300 ppm. BTW, the ZDDP cap started with SH oils.
This link also seems to be concerned mainly with high ZDDP (and moly) levels for cam break-in oils. I am not disputing this.
OT a little bit, but can you please share the source for the 5w-30 oil in Mehran? Would you have updated viscocity information for Swift, Bolan, and Cultus?