V12 tear down on bad motor

I took apart this engine, just for fun, and to learn about these engines.

I found 1 piston with stuck rings, a timing cover plug in the sump, a huge lot of sludge in the pan, and crud had run through the bearings.

I’m not sure what the small piece is, shown beside the timing cover plug.

Now what to do: wine rack? crank shaft mailbox stand?


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I personally suspect stuck rings is a far more common issue with the Jaguar V12 than most people expect, and may be the prime reason the Italian Tune-Up was recommended by Jaguar. In fact, it wouldn’t surprise me to learn that stuck rings are a common cause of engine overhauls in many types of engine, causing oil burning and low compression readings and a verdict of being “worn”.

The heads came off OK?

That sludge looks awful. Any history on the engine? What sort of oil was used? Anybody have any good ideas how to prevent such sludge buildup?

For the sludge build up that’s just down to too few oil changes, we had a lot of cars/people movers that came into NZ from Japan where the previous owners just ran the vehicles, you could tell they had zero oil changes. If you removed the sump plug it could be a couple of days before the oil had drained out.

This was from a S3 XJ12.
I guy brought it to a local Jag specialist near me, saying it needed head gaskets, and had been over heated.
The tech removed the heads, and it sure did need need new gaskets, they fell apart, and there was lots of corrosion in the heads.
Clean rebuilt heads were put on, but on start up, lots of smoke came out the RH tail pipe.
I assume now, that the piston with stuck rings would make lots of oil smoke.
At this point the owner gave up, and I bought the car for parts.
I took the engine out because I found a guy that wanted to do a V8 conversion on it.
I started stripping the engine to get my rebuild heads back, then continued to investigate.
So, I guess the customer had 2 issues, head gaskets and stuck rings.

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love to know what an Italian tune is Kirbert?? Surely the best way to stop sludge build up is to change the oil and filter and flush every 6k?

I thought everyone on this list was familiar with the Italian Tune-Up: at 2000 rpm. put the pedal to the metal and hold it there until well past 5000 rpm, then coast back to 2000. Repeat until you no longer get great clouds of black smoke out the back and the engine responds to being floored the way it should. If you’re a wuss, you do this in low gear. If you’re a real man you do it in 2nd, which is probably more effective but it’s also likely to land you in the hoosegow if the cops don’t appreciate what you’re trying to do.

And no, I didn’t make this up. It’s an official Jaguar recommendation for complaints about engine knocking and other issues with the V12.

But did they officially call it an Italian tune up? Not very British, what! Perhaps a Coventry clear out, or a British bore blaster, would be more apropos.

No, they didn’t call it that. IIRC they didn’t give it a name at all, but rather simply described the procedure. We all knew what they were talking about, though.