Good information thank you, hopefully I can get that in France. Any other good advice before I start this rebuilding adventure? I located a S3 engine I’ll pick up next week. No chance to inspect it before buying it as it’s sold for a song but it’s 4:30h drive away so the purchasing price is pretty much the transportation price. I’ll take the chance! Deceased Owner purchased it to build a XK120 replica years ago so I guess he didn’t select a bad engine.

 

I tried to get a Cometic gasket for my S3 engine rebuild, after having problems with pattern part head gaskets on the slotted block. This was through Cometic UK. It was very expensive and took ages to receive. When I did get it, it was totally wrong (for a 2.9L XJ40 engine despite very clear details being supplied to them that I wanted 4.2L XK engine for '85 XJ6). I then got a genuine Payen gasket from SNGB and that was successful, so I would recommend going that way.

 

I usually buy from Barratt, so will be easy. Thanks you for sharing your experience!!!

 

I bought my gasket from Terry's Jaguar in the USA. I think they were the ones who originally convinced Cometic to make their gaskets for Jaguar and I have been very pleased with the quality. I've used 3 now on various engines and they have worked well. They never leak, which is nice.

The extra thickness saved me on an E Type that I built for a person to be a concours car and they wanted the original block and head. It had been skimmed several times and I had to go with the thickest gasket they offered to bring the compression down to a normal range. With a standard gasket the compression would have been over 11:1

 

May I ask how to check the block height to identify what gasket thickness I’ll need? I haven’t thought of that different à compression it could produce after skimming

 

About 20 years ago Ray Livingston on Jag-Lovers developed a spreadsheet that calculated the compression ratio once you had taken a few measurements of the engine. I have attached them below, along with the instructions.

Note that Ray is in California and octane in the USA is measured on the AKI scale. It's the average of motor and research octane numbers. Europe only uses the research number and the difference is about 4-5. So 91 AKI is approximately equal to 95 RON.

 

Here is a YouTube video from a US shop on repairing a cracked e-type 4.2 litre block that has cracks between the bores. They install lipped liners
Jim's Automotive Machine Shop, Inc. - YouTube

 

If you have to do work on the block, definitely go for the top hat (lipped) liners. My feeling is that for a 4.2, the oldest blocks are often better. British Leyland 'streamlined' Jaguar's quality control and the machine tools were well past their best by the 1980s.

 

I’ll try to stay away from refurbishment as I can’t afford to spend too much on that car… otherwise I’d just redo the original engine as it’s matching numbers! The idea was finding a good used block to put that car on the road for a decent price. But thank you: very instructive!!!

 

Assuming the other engine seems reasonably ok, I'd be tempted to drop it in as-is and see how it runs. Worst case is you pull it out again. I am not familiar with Series 1 and it's throttle linkage that was mentioned earlier, perhaps drill and tap the holes in the cylinder head before the engine goes in? Then you can use the Series 3 engine complete.

 

I’ll do a healthy mix: first check compression on that spare engine. If it’s good: I’ll send out the block for crack check. 200 euros. Then, sandblasting (by me) and skimming by a pro 90 euros. New 2k engine paint then reassembly using proper quality gasket set and all my original S1 parts that are fine and will be cleaned and possibly skimmed too to ensure it won’t leak. That hopefully will work allright and keep me below 3000 euros all inclusive. Fingers crossed…

 

 

As you can see the original engine was well taken care of. The bad cylinders condition really came as a surprise!!!!

 

So I got my “new” engine. It’s a 8L serial. Old one was a 7L. Any reliable base to date the engine based on the serial? Just curious… also, what are the main differences between the 7L and the 8L? 8L are all slotted or just some? Thank you 🙏

 

 

I don't think there was any difference between a 7L and an 8L, I think was just that they ran out of numbers in the 7L series and changed to 8. I've never been able to find any conclusive differences anyway. The date on that engine is approximately April 1985.

 

The 7L engines were sleeved
8L engines not.
Major difference!!

 

Thank you, plenty of visual differences but no technical differences then. 85 would make it a slotted block right?

 

But the piston size is the same despite the sleeves?

 

All 4.2 are sleeved are they not? I've never seen one that wasn't, from E types to late XJ6 engines.