Is there a list of the resource limits placed on Automated Builds?
As an example, I ran into an excruciating two-hour (user time, I think) build limit yesterday when attempting to build HHVM on CentOS7 from source; success finally arrived with make -j2 after a few make and make -j5 failures.
For larger builds you should either break them into several Automated Builds connected by FROM statements and Repository Links, or build them locally on your machine and push them.
Please remember that the Automated Builds are a free service offered to the Docker community and try to work within the constraints provided so that we can share these resources with more people.