Hi, I have a L-visa from the CVASC in Singapore to stay in china for 60 days .

You can try to extend it from the exit and entry administration of the local PSB in Shenyang.
First, you need to provide the application form, a passport-style photo, your passport, valid registration form of temporary residence, the return ticket and accommodation arrangement. Next, submit the application to the exit and entry administration.

Hi Peter, how did you manage to get a 60-day visa in china? Are you visiting a spouse/relative? I only managed to get a 30-day tourist L type.