Does anyone know the minimum crank shaft diameters for a Cat D7 4T? My big end crank journal measures 89mm, at new it is supposed to be 92.075mm.
Thanks.

Here is a page from the Servicemen's Reference Book for the engine used in the D7 3T it should be the same. 
Craig 
 

check your parts book for oversize bearings it will show what the max oversize expected is. yes babbit bearings can be custom cast in place to any size but you dont want to be under minimum journal dia.

also check the journals for out of round. and magnaflux tested for cracks

any good engine rebuilder should be able to rebuild that crank with flame powder spray welding and then regrind to size. it wont be cheap but it will get you back to spec.