, 80, 81& 82.
I never had the good fortune or misfortune of sailing with Doxford Engines but heard many horror stories.
The records of the Doxford Company are now kept by Tyne & Wear Archives & Museums. I don't think you can get them on line which means you would have to attend in person. You can get the Ref No for articles you would wish to view on line. I found this one for 58JS3(for small ships)
Ref No DS.DOX/6/4/179
Supplement to "The Motor Ship" includes detailed plans. Hope this helps.