Volvo D16

[grease gun]

Hello everyone,i need some help , i have a volvo d16 that i am working on at the moment,i having problems with the timing, there is no timing mark on the flywheel,is there a method i could use to find the exact TDC position,i have tried by inserting a fine rod in number 1 cylinder and turning the engine to bring up no 1 piston,i did the cam timing and and every thing else,when i start the engine i am getting a pinging sound,how could i know if i am tdc,when the piston stop moving or when the piston about to move down when turning the engine manually which one is correct,

thanks