Blogging Ping Schedule

I have 4 blog sites and i daily update all after one by at a time, for example first i update one blog which take 30minutes to update then second blog and so on third and forth, so when i update all blogs it also ping google.
I have read on this forum or any other that do not send to many pings to google or they will think it as spam and will ban you, is it right ? But remember i send pings from different blogs domains.
Can i update my four blogs after one by one or i have to update two blogs at night and two in day ? Plz help i will be very thankfull

 

So long as all the sites are on seperate domains I don't see the harm.

 

I was also thinking so but it is good to get help with friends like you, thanks for first responce. Any other suggestions and comments are also welcome.

 

I would agree to space them out, just in case.

I know that external ping services will block if I ping too quickly repeatedly.