Originally Posted by
rick130
Just a FWIW on prop shaft diameters.
Measured the 130, rear prop OD is 70mm.
Nissan Patrol coil cab ute, rear prop is 91mm OD. (and quite a bit shorter, we won't mention UJ size either....) The Effie shaft is in the neighbours shed, but IIRC it's 4" or larger.
Yes, a Patrol drives through the rear diff on road, but still...and as John mentioned, a number of 130's experience vibration problems from the rear shaft 'whirling', which is the phenomenon you get when the shaft reaches its critical speed.
The smaller the diameter and longer the shaft the lower the critical speed and in theory form the charts I've seen a 70mm mild steel shaft 58" long would have a critical speed somewhere around 4-4500RPM, well above what a 130 would see normally, yet they wobble or whirl.