The tensioner pulley on my 1976 V12 didn't look right to begin with. When I loosened the belt, the tensioner just fell off. The shaft it was riding on is worn down on the left side.

Where do I get engine parts like this?

 

There is a replacement part for that from SNG.

I have it on mine...

 

I believe the part number is EAC8097 for the Jockey Pulley.

I had NEW-IN-BOX one for sale on eBay in 2006. It was the complete assy w/arm but I don't remember if I sold it or just put it a box somewhere in my 'pile-o-parts'.

I don't think the pulley/bearing is a separate part from the complete arm.

bob

 

It is a pressed in bearing.

 

Btw here is the replacement from SNG fitted to my V12...

https://www.jaguarforums.com/forum/xjs-x27-32/1989-xj-s-resto-thread-my-iron-lady-122921/page13/#