So, how can I tell by examining Superblack’s banjo bolt whether it is the correct “upgraded” version, if Jag in fact did correct their “error” later on? Or did they get it right by the '92 MY?
I am not aware that they ever corrected that error. I’m not even sure it’s Jaguar’s error; it might be some sort of standard banjo design.
I presume you want to know if it’s been corrected without having to remove it? Because with it out, it’s a simple matter to measure the distance from the underside of the bolt head to the centerline of the cross hole and comparing it to the dimensions of the collar.
Yes … so what should those dimensions be? I might get lucky and perhaps the PO made the modification … thanks …
The cross hole on the original banjo bolt is centered about 5/32" from the underside of the bolt head. It should have been about 1/4" from the underside of the bolt head. My fix was to use a Dremel to cut a channel in both sides of the banjo bolt from the cross hole about 3/32" toward the threaded end. Others have chosen to simply drill a second cross hole 90 degrees from the first one and the proper distance from the head. Or you could replace the bolt; some on these forums offer custom-machined replacement banjo bolts. You could even fab your own, just find a bolt the right length and thread and gun drill it lengthwise and cross-drill it in the proper location.
There’s virtually zero chance of an oil leak; the copper washers will seal up the assembly pretty much no matter what holes or channels you cut in the banjo bolt. Your only concern is weakening the banjo bolt so much that you snap it off trying to tighten it up.
This banjo on the radiator is easy enough to deal with. The ones on the back end of the tappet blocks are more troublesome, as they share the same mislocated hole issue and they are too short, can easily get stripped out of the tappet block if overtightened. So, some of those friendly machinists offer banjo bolts with correctly-located cross holes and a bit longer than the OEM bolt.