I am looking for a sight or any type of book that would show all the different models of diesel engines.
I doubt that you will find "all anywhere, here are two sites with many:
http://www.northeast.railfan.net/search.html
http://www.rr-fallenflags.org/
I can recommend the Kalmbach books “F units, the diesels that did it”, “E Units, Electr-motive’s classic streamliners” and also their book on Geeps, can’t remember the title. All three of these have plenty of useful information including scale drawings.
I have Gerald Foster’s ‘A Field Guide to Trains’. ISBN 0-395-70112-0 I won’t say it’s the most comprehensive, but it does have many great drawings of diesels. Mr. Foster is an artist and architect, as well as a railfan.
The book points out differences in the various models, such as an EMD SD40 and SD40-2, as well as a basic specifications feature for most of the models.
The books you need are: Diesel Locomotives: The First 50 Years, covering the first and second generation diesels, and Field Guide to Modern Diesel Locomotives, which looks at engines from the 1970s onwards.
Look here: http://store.yahoo.com/kalmbachcatalog/railroading-books-railroad-reference-series.html
You might also want to check out Model Railroader Cyclopedia, Volume 2: Diesel Locomotives.
Look here: http://store.yahoo.com/kalmbachcatalog/model-railroading-books-model-reference.html