Looks like to me that if you tried to mix the XK120 shaft with the later XK150 bushing the distributor drive would sit too high? But that would also make the oil pump drive too short, so you probably would not be able to fit the drive gear either.
Is the distributor drive offset clocked correctly? That’s the most common cause. Here’s the same shaft and bushing with a distributor drive inserted. If the drive is out 180 degrees, the offset built into the drive dog won’t allow the distributor to drop down.
(The brass bushing and thrust washer are not installed correctly in the photos below)
Further to Mike’s excellent explanation, here are the part numbers.
Drive shaft of the XK 120 and the early XK 140 is Jaguar C.2150; the (shorter) Bush had Jaguar number C.2174…
Later XK 140 and (all?) later XKs used Drive shaft C.8646, combined with (longer) Bush.C.8647.
thanks to all who have provided info and pics so I just need the steel shaft as shown in 2 on left.
Does anyone have spare for sale?
terry tmcgrath@bigpond.com
Terry, post in the classifieds section. I’ll check in the garage tomorrow as I think I might have one, but not sure if there is any difference between distributors?