The V8 Owners Forum -

Hi I am thinking of buying a Daimler XJ8000 (I think that is the model) with a stuffed 4.0 v8. I hear these engines are not a terribly good engine, so I had considered changing it to a... V6 duratec for reliability. I would prefer to stick with the v8 but I cant be let down on the spot. There is obviously going to be a lot more work required and money spent to change to the v6 and possibly other added problems. Can anyone give me any advice on this or let me know how to solve the issues with the Jag engine?
Any help would be grateful.
Thanks Mark

Hi
The v8 jag engine and the duratec V6 are both based on the 4 cylinder mazda engine (4 cyl duratec when ford badged) so appart from effectivly chopping 2 cylinders off you are using the same unit. The jag V8 pre 1998/ 1999 had two issues, firstly it had a problem with the nicosil lining of the ally bores on the cylinders, in that when fed on a diet of low grade supermarket cheepo high sulfur petrol the coating flaked off and the bores wore out very quickly, secondly there was a problem with the cam chain tensioner on pre (I think) v plate engines. The nicosil problem was fixed with a change to iron liners for the block after P plate and the cam chain tensioner was fixed with a redesign and replace on cam chain service.
My wife has had an xk8 on a W plate for 3 1/2 years and about 20k miles now and we have only 1 issue to deal with, a split water header tank that was dripping water out, apart from that I think it is the most sophisticated smothest engine with the best power delivery I have ever driven bar none it makes me (and my wife) smile from ear to ear whenever we drive it, it is (I think) a loverly engine! The car will cruse all day at 80 mph and deliver 30+ to the gallon on a long run and 23 plus in general use.
If you decide to change the engine you will have some issues, the throttle is a drive by wire set up, the butterflys are opened by the ecu and the ecu controls the engine and a seperate one the gearbox and the engine ECU takes inputs from the gearbox ecu and visa versa, you cannot just replace the engine and not have some way of sorting out the gearbox ECU. for "sport mode" the whole lot takks to the damper control and back axel ECU that sorts out traction control (by gear selection and throttle position) and the LSD.
If you want to go for a different engine then you would find life easier if you changed the engine and box together and dumped sport mode.
As the XJ8 are so cheep thoughI can't see why you would buy one with a worn out engine, just look out for a sub 150k mile post 2000 car and enjoy it.
Best regards
Mike

Thanks Mike. Very useful bit of information. Is there any upper limit to the age of the engine I can fit, the car I am looking at is 1999.
Cheers Mark

Hi Mark
In answer to your question, it depends what you are prepared to change, engine and gearvox and ecu as a unit then really no if just the engine then the 4 litres are basically supercharged and non supercharged, and both have a 5 speed auto with locking torque converter, you will need a matching map in the ECU of both engine and 'box but if you are replacing a 4litre NA engine with the same thing then it is really a straight swap in and out, if you are swapping a supercharged engine into a non supercharged car then you will need to get the ECUs re-mapped. If you want to swap a 4.2 (supercharged or non) into a 4 litre car then there is another issue here as the 4.2 had a 6 speed box (with lock up TQ) however, the ECU seems pretty sophisticated as it adapts to driving style and I suspect actually just sticking a 4.2 NA engine in a 4 litre car with it's original ECU it would just think it had good petrol and a driver who eased off the throttle a bit earlier/ had a lead foot depending on how you drove it. Keep it simple though and swap whole units (engine gearbox and ECUs) and it will be just that. Lastly there is the 3.2 litre V8 fitted to some XJ cars, they have a reputation of being absolutly bomb proof, including the supercharged ones, but relativly gutless and nothing like as relaxing to drive as the 4 litre, but in supercharged form and abused mercilessly they are meant to make for a very quick (and very large) car! here again you will need to get the right gearbox ECu and in this case probably matching torque converter. I was leant a long wheel base supercharged 3.2 for the weekend by a garage, It was great fun, not at all like the XK in that the XK feels like you have to rain it in and exercise a little self contol all the time, it felt it needed to be pushed, but it was quick and handled well but quite thirsty compared to the XK (though if it had done a run I suspect it still would have done high twentys.
Best regards
Mike

The jag engines were changed to steel liners from 2000MY
there are 3 revisions to the timing chain tensioners, you want revision 3.


The 3.2 was never supercharged, this was 4.0 only and later the 4.2 (2005 on i think).

"The 3.2 was never supercharged,"
Funny, the one I drove was, the charger sat in the V on top of the engine just like on the 4.0 right where you would expect it, 3.2 sport written on the back, brembo brakes fun car.
Best regards
Mike