The nominal standard bore is the same, yes.

 

Well: I’ll be able to answer that once and for all after we open up that 8L engine 😊 ‘85 year making it one of the last since it stopped in ‘87 right? I know they were used till 92 In Daimlers limos but I’d guess no changes were made on such little produced engines

 

 

It's amazing how much Jaguar changed things back and forth. No wonder it cost so much to build these cars.

What does it look like looking from the bottom of the bore looking from the crankcase side? Can you show a close up of one cylinder please?

Looks like liners up to engine number 8L89108, no liners after that.

 

The limos were carbs right to the end, they never got EFI, so I also don't know if they ever had the big valves, or stayed a Series 2 XJ spec. I have one, but I'm not inclined to pull the head off it!

 

Very interesting!!!! So if it has liners up to 8L89108 my 8L180012 must not have liners right? If not it’s getting more confusing… it’s better with liners no? Im wondering why Jag removed it. Normally car construction improves over time with experience. It’s known later series are always better engineered. At this point I’m wondering if I should look for an earlier engine block from a series 2 instead.

 

I'm sure your engine will be fine, I wouldn't look for a different block based on that. If things are really bad, you could always resleeve your exisiting block, but that gets expensive.

 

Not true
My 1980 8L 4.2 block was sleeved, but later engines with the slots between the bores were not sleeved. The 4.2 engine carried on in production for far longer than Jaguar intended, the AJ6 all alloy replacement came out in 1984 having been rather too long in development. Jaguar was run on an absolute shoe-string at the time, with profits almost non-existent, and all the production machinery well worn out. Ford had a huge shock when they looked over the Jaguar factories after purchase, (they didn't do any due diligence !!). So the slotted blocks were the last mod to the engine, and pretty much a quick spatchcock knowing the AJ6 engine, and the XJ40 saloon was imminent.

 

When I had to fix my 1980 XJ6 engine due to cracking, I managed to obtain an uncracked standard size bores block from a chap in Hinckley in Leicestershire who rebuilt them. This was a 7L block, mine being an 8L. He told me 7 out of 10 7L blocks and 8 out of 10 8L blocks were found to be cracked when dismantled. The cure he used was to install lipped liners.
So when rebuilding an engine, it is important to check for cracks, because if present the car will just blow its head gasket every few thousand miles for evermore. The slotted blocks don't suffer the cracks, but the limited area for seating of the head gasket around the bores means head gaskets do fail, but only after many thousands of miles. For a car not in daily use this is normally OK and the car will run for years and years. The ironic thing is that the later, all-aluminium AJ6 engines also suffered head gasket failures too, for no obvious reason.

 

Thanks to you all I’m beginning to be knowledgeable about 7L and 8L XK blocks 😊 I haven’t had the time yet to open that engine but camera shows marks of machining and polished surfaces in the cylinders: so it looks like the seller was telling me the truth about that engine being low miles.