The ultimate upgraded rear main thread

I used Hylomar and I believe “Right Stuff” (been a while ago). There’s no silicon in my engine.

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Were it my choice, Id do the Rob Beere one.

Of the couple hundred rope seals I installed, on all manner of engines, I can say they are never perfectly leakfree for long.

Remember, back in the day, folks didn’t obsess on engines being leak-free, as that state was virtually impossible, without modern sealants and gasketing materials.

Engines leaked.

Rope seals will seep a drop or two, after a while, and that’s just the cost of the much-vaunted ideal of “originality.”

In the case of the XK engine, I never used the sizing tool, only the crank, and all turned out satisfactorily. Ditto on all other rope-sealed engines.

As for the hyperventilating that goes on about the use of silicone, I used it extensively, and ALWAYS sparingly, with excellent results, on thousands of engines. There are now other sealing materials that work as well, or better.

‘There’s no silicon in my engine.’

Maybe not siliconE, but there’s a ton of silicoN…:laughing:

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How do you establish concentricity with the tunnel bore?
If I were using the crank method, (which I have never done as I have the tool) I would install the top half roughed in followed by the crank with #'s 1 & 7 bearings and caps. Bottom half of the seal housing drawn down to finish.

It’s not really an originality issue for me, at least until they start putting JCNA judging pans under cars to make sure there is the expected leak. :joy:

I just don’t want to make a bad choice.

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Wiggles I agree with you that you probably will get a few drops of oil out of a rope seal - it’s not perfect, but is anything? You also get some oil leaking from the lip seal on the front of the crankshaft as well, and grease coming out of the lip seals on the axles. Thankfully it’s all very minor. (Leaks from the front of the crankshaft are minimized if you use the spacer from a later XJ6 which has a groove cut inside of it for an o ring between it and the crankshaft) I would anticipate that the lip seal mods for the crank rear will also seep somewhat, but I would seriously consider using them.

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Doug when you assemble it on the crankshaft while out of the engine, you do so on the actual surface of the oil slinger. This immediately abuts the back of the flange, which aligns the seal retainer to the crankshaft.

To Wiggles’ point, here is a photo of Sir William with the “new” Jaguar XJ6 and development team in the car park of the plant. Look at the oil patches on the ground…




This is the lot where the new cars are staged? That picture tells it all.

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Ha! That’s even funnier than the leaking museum car.

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Hi Terry,
Yes, hopefully we are all aware of which area the seal interfaces.
How does this method insure concentricity with the seal race?
I don’t see it as an advisable workshop practice.

I was shown this way by a professional mechanic friend who for years had a Jaguar repair shop, which at the time (35 plus) years ago dealt almost exclusively with XK engines. I’ve done dozens of engines this way without ever experiencing a failure, he probably did hundreds. Is it advisable workshop practice - I don’t know - it works for me and for him. All you are really doing is ensuring that the seal is fully embedded into it’s carrier. IMO it retains some flexibility and will mold itself to the slinger when it is bolted to the block. Ultimately the proof is - does it work, is it efficient, does it minimize potential damage to the area you are working in.

Ultimately I can’t see how it’s much different from using the factory mandrill. However the factory tool has a handle, and watching the mechanic seat mine, the rotation seemed to be a big part of gradually seating the seal in the carrier. How would one rotate the crank?

The crankshaft is out of the engine – so you rotate the seal carrier around it.


Ditto: not only Jaguars, but many other British cars with rope seals, and a plethora of American cars, all done w/o any fancy sizing tool, all were perfect, as far as the design allowed. The number I did goes into the many hundreds.

Done correctly, it works.

Proves the point: folks back then didn’t see minimal oil leaks as a reason to lose their sh!t…:smiling_imp:

That said, it would have made a nicer, if less-honest picture, to stage the photo on a newly-blacked and striped lot!

I’m curious Paul…
How is it done “correctly”?

Nope they don’t work at all. Out of desperation I used Bars rear main oil seal and it didn’t help one bit just a waste of money. I called Bars before using it and was told it would do the job.

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Agreed: there is NO “rope seal repair in a can” that works.

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The factory would have saved a lot of money if just cramming it against the crank would have worked. However, the seal is not supposed to rub on the crank, but just barely float against it. If you do this job often, you probably already have the tool. If not, it is for free loan to JCNA members. As far back into the engine and car to fix it, why not take instructions from the people that built and designed the engine as to how to install it? BTW: the parking lot was the employees parking lot, not the new car lot. Poor choice for a picture anyway.