There is a reason those engines are in "SCRAPYARDS" - no-one throws away perfectly good engines and about 90% of the engines you buy in scrap from Pakistan are literally scrap. The warranty/grantee, bhaibandi, bhaichaara etc etc. are useless as the people performing repair work only think that if engine is rotating - its good to go.
I have repaired countless swap wirings where peshawari ustaads had wired literal 1 injector driver to run all 4 injectors because "pulse pulse hoti hai"
I used to repair automatic transmissions and it was hilarious to meet customers on their 4th junkyard transmission with shift issues. The perfect remedy was always to do a full tear down and rebuild it from bottom up with new wear parts. Those transmissions worked like brand new with absolutely zero issues - infact better as better/updated parts in the valvebodies were installed (e.g. Honda oil charging circuit causing burnt/blue torque converter)
It was equally LOL and super hilarious to meet people who were running no radiator cap and dumm ka pani coolant on 1KZ-TE diesel because "jenyan head ka pressure nahi aaraha geskut kaam ke baad" - where I would see same peshawari/quetta/torkham/pindi/lahore/karachi dumbass ustaads reuse the cylinder head bolts..
TL;DR
do the job according to repair book published by manufacturer - if they mention special tools, buy them or make sure mechanic has them, make sure mechanic is actually mechanic and not plumber/cobbler/handyman doing mechanic work that day.
The old adage of "you reap what you sow" - expecting perfection from junk is playing russian roullete - you can win a big hand or get shot, take your choices and make your bet.
The above is written on personal experience in and outside Pakistan.
