The original poster is a foreigner. That seems to be variable timing, and neither the camshaft sprocket nor the crankshaft sprocket has keyways. If this is the case, it is not the outer eight and the inner eight. Use special timing tools. I remembered that I really need to use a special timing tool. That set of tools costs more than a thousand. You can check it out on Taobao.com. What a cheat. But you can do it yourself with the tool. It's not difficult, I've done it. The materials cost dozens of yuan, and the lathe processing also cost dozens of yuan.
It only costs a few dozen yuan if you can make it yourself