Not if those 4 words are in the dictionary. Crackers are definitely aware of this password generation technique and it isn't hard to run through 4 word combinations from a dictionary.
In the end, the best password right now is a 16+ random password made up of uppercase letters, lowercase letters, numbers and symbols. Use a password manager to manage and store your passwords.
It depends on the size of your dictionary. If you want to run through all combinations of 4 words from a 131072 word dictionary you need to test 2^68 combinations.
In the end, the best password right now is a 16+ random password made up of uppercase letters, lowercase letters, numbers and symbols. Use a password manager to manage and store your passwords.