More Information on the Engine Test Results

So, for the first time since I purchased this game I have decided to go through all the scenarios. Doing this had made me realize that I have not learned anything about which components control what in the results. For Example, I have been having a horrible time figuring out "Reliability", I can't find anything that increases reliability either. It seems that my reliability either holds at a specific peak or drops bellow that, but I can't find a way to improve it. So I'll build an engine and run a test and then get 55 reliability. I'll go through and try changing different components but I can never get it above 55.
Anyone know of a general breakdown for what results relate to different components in the engine? I've tried looking at the manual for an idea but haven't been able to find any information.
Anyone know of a general breakdown for what results relate to different components in the engine? I've tried looking at the manual for an idea but haven't been able to find any information.