Hi , I have a question about Jaguar xj6 engines. I own a 84 xj6 lhd series 3, 4.2 broken engine.Can I swap 4.2 engine block from series 2?
If there are Some differences Can I fit the engine to a fuel injection head?
Thaks so much in advance for your help.

 

Yes, it should be a direct swap. Heads are the same, you might need to swap over some ancillaries, like the distributor and oil filter mount, but everything will bolt on.

 

So what is broken in the current engine ?
If you decide to buy a Series 2 4.2 litre block, it will be a "7L", your current one will be 8L. Both blocks were notorious for cracking between the bores causing unending head gasket failures, (my 1980 car was typical). So if you do decide to go ahead, you need to inspect the area between the bores very carefully for cracking, Later 8L blocks were "cured" by a typical Jaguar spatchcock of cutting slots in the space between the bores and eliminating the liners. Your current block should be of this later type if it's an 84. So why this "quick fix" ? Well, the old 1948 XK engine design was on the way out in the early 80s, with the all-alloy engine coming in, so significant spending on the old engine was just not economic. The XJ40 saloon was about to come on sale, (actually it was late !), and would use the new AJ6 3.6 litre all-alloy engine.