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  1. #1
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    What actually happens?, Nikasil problems

    First off I want to say how glad I am that I found this forum. Now to my question.

    The problem that I have seen associated with the nikasil bores in the 8 cylinder engines is that of low compression. From what I have seen here is that it may be caused by high sulfur fuel. My question is:

    “What has happened to the engine that has caused the compression to be low?”

    Are the piston rings gummed up, have they lost their sealing ability?

    “What has Jaguar done to solve this problem?”

    Thanks in advance, this is my first post.

    Ken




  2. #2
    Richard
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    Re: What actually happens?, Nikasil problems

    This is from the X300 forum at Jag-lovers.org:-

    Jaguar UK dealers are required to check V8 engines at every service
    interval for premature bore wear. This check is specifically for
    all XK and V8 XJ vehicles up to and including 1999 MY in the VIN
    range (last 6 digits)

    XK Series 001036 - 042775
    XJ Series 812256 - 878717

    The check involves measuring piston 'blow-by' using a blow-by
    meter. Where the blow-by exceeds 40 liters per minute, the engine
    needs to be replaced.

    Background Information Provided by UK Dealers to Affected Customers:

    The AJV8 engine was introduced by Jaguar into the XK range in 1995
    and into the XJ range in 1997. The engine had an aluminium block
    with cylinder bores coated with Nikasil (nickle silicon). This was
    cutting edge technology at the time and had the advantage of
    reducing weight and cutting down the warm up cycle.

    Premature bore wear problems subsequently appeared in Nikasil
    engines with Jaguar, BMW and other engines affected. This is
    thought to be caused primarily by high sulphur petrol (gasoline)
    which was prevalent in the UK during the late 90s. Sulphur content
    can vary widely, depending on the levels in the crude oil and also
    the levels set by legislation in each country. In the UK, sulphur
    levels were reduced by law in January 2000.

    Symptoms of premature bore wear are difficult cold starting. The
    previous Jaguar 6 cylinder engines are not affected. As a result of
    these problems, Jaguar introduced cast iron cylinder liners in
    place of plated bores for all AJV8 engines from the 2000 model year
    onwards.

    Jaguar have been replacing engines of affected cars who fail the
    blow-by test under warranty at up to 100,000 miles (160,000 km) or
    5 years. Any remaining warranty is automatically transferred to a
    new owner. If an engine is replaced under warranty, the warranty on
    the replacement engine will be the same as the warranty remaining
    on the vehicle, or a period of 12 months, whichever is the greater.
    Replacement engines may be identified by the presence of a re-
    manufactured ident label on the cylinder block just below the rear
    of 'A' block cylinder head.

    The best advice to owners of Nikasil engined cars would seem to be
    a) stick to low sulphur gasoline bought from the major oil
    companies (not discounted supermarket outlets). and
    b) do more frequent oil changes that the service schedule requires
    (cheap insurance)
    c) keep up the Jag warranty if possible.

    If you are thinking of buying one of the affected cars, check to
    see if the engine has already been replaced and /or insist on a
    blow by test before you commit yourself.

  3. #3
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    Re: What actually happens?, Nikasil problems

    Thanks for the very detailed response.

    If the actual cause of the low compression is worn cylinder bores how would you explain the following?

    It is a common occurrence for cars with these engines to get towed to a repair shop with a crank but no start condition. A compression test reveals low compression on all cylinders, as low as 20 psi. The “fix” is to squirt a little ATF down each cylinder and change the plugs. You then push the car outside and crank it over until it starts. You let the ATF burn off and then go test drive. After that the compression is back to normal and the engine runs perfectly. I have done several of these and the cars don’t come back. This happens all the time and the “fix” is well known to anyone who works on Jags.

    This “fix” implies a problem with the rings not sealing, not a problem with the cylinders bores, in my opinion.

    Anyone care to comment on this?

  4. #4
    fat-cat
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    Re: What actually happens?, Nikasil problems

    What is ATF ?

  5. #5
    Richard
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    Re: What actually happens?, Nikasil problems

    Isn't the problem you are referring to caused by excessive over fuelling on startup washing the oil out of the bores causing loss of compression. This usually happens when the car is run for only a few seconds when the engine is cold. I think that there was a change of software to help stop this happening.

    Nikasil is a more permanent failure. I do wonder though how many engines have been changed unnecessarily.

  6. #6
    Grumpy
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    Hey, they gotta make money somehow

    You are correct that the two problems could be confused. It's easy for a tech or service advisor to spend someone else's money and say "new engine time."

    My understanding was the problem you mentioned was due to cylinder flooding, while Nikasil failure was due to worn linings. Either way you'll end up with tolerances out of spec and low compression.

    I've not yet heard of using ATF for the washed-out oil issue, do you use D4 or D3 or what? Thanks in advance.

    (For those not following his washed-out cylinder fix it's pretty straightforward and could be done in under 2 hours even by a dummy such as myself. Personally I'd clean instead of replace the plugs since they're pretty expensive as in $30 a piece retail. Thus if someone has a potential Nikasil failure the ATF fix is worth a shot since it could be done for about $200 using an honest shop ... beats the hell out of ten grand or so.)

  7. #7
    Grumpy
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    Auto transmission fluid, cheap stuff

    Even quality Mobil 1 D4 ATF is only about $5 a quart. Also used as power steering fluid in many modern Euro cars. The "lifetime" Esso ATF is substantially more expensive but I see no reason to use it to prime a washed-out cylinder.

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    Re: Hey, they gotta make money somehow

    I guess I have not seen my first real Nikasil failure, I also wonder how many engines have been needlessly replaced.

    I doubt it matters what ATF is used, its mostly a matter of improving the compression enough to start the engine. I speculate the high detergent additives may help loosen up the rings???


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    Re: What actually happens?, Nikasil problems

    That scenario is much more common than Nikasil failure. We use oil instead of ATF but the result is the same. Usually takes a long time to build compression and start.

    If the compression does not come back, the engine won't start and cyl wall failure is usually the problem although I have seen one car with rings so gummed up that they would not move and seal.

    Once the car starts and is warm, a leakdown test will show if you have cyl failure. Easy test is to pull off the full load breather while the car is running. If the rings are going bad you will have lots of blow by gasses coming out at idle.

    Vic

  10. #10
    Grumpy
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    Higher viscosity also might help

    ATF is more "goopy" than normal engine oil so might help close up the gaps better.

  11. #11
    Real Tech
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    Re: What actually happens?, Nikasil problems

    The cylinder washout can happen to non nikasil engines. A couple of short starts to move the car from the garage to the driveway and back can due the trick. I've seen this on '02 and '03 cars which are not nikasil. I've also seen this on other brands, it is not a Jag only problem.

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    Nikasil -- it\'s a GOOD thing!

    . . . unless you live in a high-sulphur area, and even then: (a) your engine has already been replaced, or (b) you bought your gas at one of the brand-name chains who went low-sulphur before being required to by law. Either way you are off the hook.

    These days, sulphur is becoming almost as rare in American gasoline as WMD are in Iraq. Which can only be GOOD news for us Nikasil-engine owners, because we will soon be able to drive in less fortunate areas of the country, like Texas! (J/K - I don't know the current sulphur levels in the Lone Star state.)

    Here is an excerpt from a letter written by one Marilyn Bennett of the EPA, in reply to my request for information about regional suplhur levels in gasoline:

    "The federal gasoline sulfur regulation requires all refiners and importers of gasoline produced for use in the U.S. to produce low sulfur gasoline beginning in 2004. The regulation provides for a phase-in period in which refiners and importers must meet a 120 ppm average sulfur level in 2004, a 90 ppm average in 2005, and a 30 ppm average thereafter. There are also per-gallon "cap" limits to ensure that no gallon of gasoline will contain an unusally high sulfur content as a result of averaging. Many refiners will be producing gasoline with sulfur levels well below these limits. We believe that the federal low sulfur program will significantly reduce the average sulfur level in gasoline nationwide."

    As luck would have it, the manufacturers (BMW, Jaguar and other premium lines) phased out Nikasil just as the gas companies were phasing out sulphur. Today, a few years after the fact, whatever damage was going to be done by the stuff has already been one. For the vast, VAST majority of Nikasil-engined owners who have NOT been affected by high-sulphur gas, our now middle-aged engines are about the reap the benefits of Nikasil, among which are longer engine life and a pleasant reprieve from the decrease in performance and fuel economy that usually accompany higher mileage. (I know this for a fact. When I sold my Nikasil-engined 1995 BMW 740i it had 120K on the clock and was as tight as new -- BMW's leak-down test confirmed the engine's compression was at "new" specification.)

    Nikasil is a far, FAR more elegant solution to the problem of heat management in alloy engine blocks than cast-iron cylinder liners. Nikasil technology is still used in the finest piston aviation and racing engines, which have have never suffered from sulphur headaches: pilots and racers always use reliable gasoline.

    In fact, there was never anything wrong with Nikasil in mass-produced automobile engines. It was the gas that was bad, and finally it's better.

    It's been better since 1996 here in California, so my car was never at risk. When and IF I ever sell my 1998 XJ8, I'm going to ask a PREMIUM for the Nikasil engine! In the meantime, I look forward to a few hundred thousand miles of enjoyable motoring all over the country.
    John Mulvihill, technical writer, San Francisco Bay Area
    1998 XJ8, Anthracite/Charcoal

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    Re: What actually happens?, Nikasil problems

    I totally agree, I first started to see this with the AJ6 engine.

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    Re: Nikasil -- it's a GOOD thing!

    Thanks for your contribution, very informative. This whole subject brings up some other things that need discussing. You seem to be up on this high sulfur issue. As a way of ending this topic could you please answer just one more question?

    “What is it about the sulfur content in fuel that is detrimental to Nikasil bores”?

    What is happening? Does the sulfur act as an abrasive? Is the Nikasil plating being worn off exposing the aluminum?

  15. #15
    Grumpy
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    Wild guess: sulfuric acid eats nickel-silicon?


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    Just Google Nikasil and sulphur

    There are tons of archives all over the Web that describe the effects of sulphur on the Nikasil coating.

    Sulphur is as damaging to human lungs as it is to Nikasil and it's a crime that high-sulphur gas has been permitted to remain in the USA for so long. Sulphur can be removed from any gas -- it's an expensive process, so the refiners would just as soon avoid having to do it. Just goes to show who really calls the shots around here.

    Our high-sulphur diesel fuel has kept us out of the new-generation diesel revolution that has swept Europe. Their diesels run smoke-free and give fantastic performance, but they can't be brought here until the sulphur is removed from diesel fuel (which it will be by 2008).
    John Mulvihill, technical writer, San Francisco Bay Area
    1998 XJ8, Anthracite/Charcoal

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    Re: Just Google Nikasil and sulphur

    Here is a good link that gives most Jag owners the information they need, thanks for the Google suggestion.

    http://www.jag-lovers.org/include/iv.php3?in=/cjw/nikasil.jpg


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    late-1998 build XJR, 37k miles

    Hi Everyone:
    OK, so I recognize that my car is one of the Nikasil units, but as it was delivered in California and has remained, (to the best of my knowledge), here for its entire life, might I have dodged the Nikasil "bullet" at this stage?
    I do wish I had educated myself better before buying it as a Jaguar certified used car from Marin Jaguar. Do you think i should ask them to perform a leakdown test on it as it is still under warranty? Am I worrying too much?
    As usual, a little knowledge is dangerous...
    Cheers
    Andy Smith
    Greenbrae, CA
    1999 XJR BRG

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    How much DOES a new shortblock cost?

    With all this talk of Nikasil, what does a new or used steel liner shortblock go for these days?

    If it's cheap enough, it might make buying the $23,000 1999 XJR more attractive than buying the $36,000 2001 XJR.

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