Oxymoron? For some reason I keep looking at mid 90s through early 2000s XJRs. Is the I6 better or worse than the 4.0 V8 for maintenance and reliability? The supercharged I6 intrigues me as well, crazy how cheap lowileafe examples of these cars are.
Any experience or info would be much appreciated. Pondering my post TDI buyback next car. Michigan roads are bad enough that a comfy luxobarge is appealing.
Engine-wise, those AJ16 I6s are pretty solid, even in supercharged form.
IIRC as long as you stay on top of supercharger rebuilds, the six is pretty stout. The V8s on the other hand had timing chain issues from what I've read. I would probably lean towards the six myself, as it was the ultimate evolution of an ancient engine, while the V8 was a "new" development at that time. Plus I love the sound of a good inline six!
pointofdeparture wrote: ultimate evolution of an ancient engine
Not quite. The AJ16S (supercharged 4.0 I6) was derived from the AJ6 3.6l I6 first used in the late 80s for the XJ40 and the later XJ-S. It's pretty much totally un-related to the older XK 6 cylinder.
And how bad of an idea would daily driving something like this be?
http://bringatrailer.com/listing/1973-jaguar-xj6/
Its not a bad idea at all. That's a damn fine classic DD at $4600.
Beautiful but for a dd I'd stick with a 84 to 87
markwemple wrote: Beautiful but for a dd I'd stick with a 84 to 87
How come? My thoughts (and I could very well be wrong on this) is that the older car has simpler electronics etc than the newer car and therefore more reliable?
And they're gorgeous!
Do some research. All signs show the last ones were the best.
Storz wrote:markwemple wrote: Beautiful but for a dd I'd stick with a 84 to 87How come? My thoughts (and I could very well be wrong on this) is that the older car has simpler electronics etc than the newer car and therefore more reliable? And they're gorgeous!
The earlier electronics are simpler, but the later electronics are put together better and have a much better shot at actually working.
Storz wrote:markwemple wrote: Beautiful but for a dd I'd stick with a 84 to 87How come? My thoughts (and I could very well be wrong on this) is that the older car has simpler electronics etc than the newer car and therefore more reliable? And they're gorgeous!
By simpler electronics you mean ancient British electronics. Simple yes, easy to deal with as a DD in 2016? No.
It would be a fun toy but DD a classic Jag? I can't say that I would recommend that and I have DD'd some ridiculously foolhardy stuff.
In reply to markwemple: It depends on you.. The early big grill models had the last body Sir William Lyons had a hand in designing.. He also designed the XK-E, (described as the most beautiful car ever made by Enzo Ferrari) The XK120, The "D" type.... When they went to the latter rubber buggy bumpers I feel the elegance was lost.
The early ones had carbs while the later ones had the first fuel injection with all the development troubles that followed.. The carbs are about as simple as they can get. When they do finally start acting up remove the 4 screws on the dashpot pull out the rubber diaphragm and replace it. Problem gone..
The later ones suffered from fools (pretending to be mechanics) who started to learn about fuel injection. Plus they had all the development issue's any new system has (they just were at the forefront).
rslifkin wrote:pointofdeparture wrote: ultimate evolution of an ancient engineNot quite. The AJ16S (supercharged 4.0 I6) was derived from the AJ6 3.6l I6 first used in the late 80s for the XJ40 and the later XJ-S. It's pretty much totally un-related to the older XK 6 cylinder.
The older six had a Cast Iron block, 2 valves per cylinder plus an insanely long 4.16 inch stroke and narrow bore designed during WW2.. The later one had an aluminum block and 4 valves per cylinder with a shorter stroke and bigger bore.
General Motors thought so much of the power and reliability of that engine they bought it, brought it back and Americanized it.. It wound up In the Chevy Trailblazer and other SUV's of 2008.
rslifkin wrote:Storz wrote:The earlier electronics are simpler, but the later electronics are put together better and have a much better shot at actually working.markwemple wrote: Beautiful but for a dd I'd stick with a 84 to 87How come? My thoughts (and I could very well be wrong on this) is that the older car has simpler electronics etc than the newer car and therefore more reliable? And they're gorgeous!
Lucas electronics is both good news and bad news.. To keep the price of his cars low Sir William Lyons bought the lowest (cheapest) grade of anything. The aftermarket replacement parts are mostly much higher grade.. It seems that once the car is sorted out and the loose ground wires tightened up (I swear the British assembly workers had some of the weakest wrists in the world) suddenly the cars became reliable..
frenchyd wrote: General Motors thought so much of the power and reliability of that engine they bought it, brought it back and Americanized it.. It wound up In the Chevy Trailblazer and other SUV's of 2008.
This is just a rumor and not actually true. The only thing in common between the 4.2 liter XK engine and the 4.2 liter Atlas I6 is the displacement. The bore/stroke are different, the Atlas is an aluminum block and 4 valves per cylinder.
frenchyd wrote:rslifkin wrote:Lucas electronics is both good news and bad news.. To keep the price of his cars low Sir William Lyons bought the lowest (cheapest) grade of anything. The aftermarket replacement parts are mostly much higher grade.. It seems that once the car is sorted out and the loose ground wires tightened up (I swear the British assembly workers had some of the weakest wrists in the world) suddenly the cars became reliable..Storz wrote:The earlier electronics are simpler, but the later electronics are put together better and have a much better shot at actually working.markwemple wrote: Beautiful but for a dd I'd stick with a 84 to 87How come? My thoughts (and I could very well be wrong on this) is that the older car has simpler electronics etc than the newer car and therefore more reliable? And they're gorgeous!
Im convinced its because they call them earths.
I was looking at xj8s and the transmissions always seemed to be what was broken.
So if i was to want a supercharged jag, what model would i have to get? Also would a supercharger fit onto a non supercharged motor if they are the same series? Perhaps bolt on or like a "top swap" like whats done with the supercharged gm v6. If not supercharger what about turbo? Im trying to learn about these older jags, they have intrigued me and yall saying they (inline6) are pretty stout aside from sometimes the electronics makes me more so. I guess none in the states had manuals? Or am i better off finding a v12 and trying to run it until i cant and when a gm v8 takes it place. Final bit, because the v12 came with a gm trans, would it be easy enough to put a v8 and th400 into a 6cyl car or is it more difficult than the 12 cause they already have the trans?
Sorry for bombing this thread but similar questions and i dont like starting new threads.
The supercharged I6 came in the 95 - 97 X300 platform XJR (AJ16S engine with an Eaton M90 on it). The auto in those is apparently a 4L80E, so they should be pretty bulletproof cars mechanically.
And the X300 XJR came with a manual trans in Europe, so... 
In reply to rslifkin:
Thats what i was thinking, in the xjr, i saw one in a junkyard years ago just looking under hoods. Shame someone scrapped an xjr
I have my eye on a s type R. It is an 06 with 26k they want 15k for it. Has the 4.2 with a 112. 400 hp. Add a pulley and you you get to 450. You can go well north of 500 hp if you want but reliability becomes an issue.
I was driving my friends xk8 type R with those mods yesterday and it is great fun.
Oh and supercharger wine is really addictive. 
dean1484 wrote: Oh and supercharger wine is really addictive.
Sounds delicious.
rslifkin wrote:frenchyd wrote: General Motors thought so much of the power and reliability of that engine they bought it, brought it back and Americanized it.. It wound up In the Chevy Trailblazer and other SUV's of 2008.This is just a rumor and not actually true. The only thing in common between the 4.2 liter XK engine and the 4.2 liter Atlas I6 is the displacement. The bore/stroke are different, the Atlas is an aluminum block and 4 valves per cylinder.
Apparently you don't read the trade magazines.. Jaguar was up for sale and deeply in debt to GM For decades worth of transmissions etc.. GM was doing it's due diligence with plans to buy Jaguar.. Upon looking it over they discovered a lot of tooling that existed in the 1940's and was past worn out. The only thing new was the 4.0 aluminum block 4 valve head in line six with a fantastic reliability record. Rather than walk away GM bought the engine and tooling Just before Ford Swooped in with a fantastic Bid. GM brought the engine here and Americanized it.. That is they sourced American components and increased it to 4.2 from the 4.0 it was at in Jaguar's hands. The ancient 4.2 had nothing to do with the engine that eventually wound up in GM's SUV's such as the Trailblazer/Envoy etc..
Storz wrote: Oxymoron? For some reason I keep looking at mid 90s through early 2000s XJRs. Is the I6 better or worse than the 4.0 V8 for maintenance and reliability? The supercharged I6 intrigues me as well, crazy how cheap lowileafe examples of these cars are. Any experience or info would be much appreciated. Pondering my post TDI buyback next car. Michigan roads are bad enough that a comfy luxobarge is appealing.
It depends on you.. If you are the type of person who when things go wrong, run to the dealer or your local mechanic you will soon tire of high priced repairs that may not actually be right.. Then Jaguar ownership is not for you.. OH the cost of repairs won't be higher than say the Mercedes, BMW, or Audi but the mechanics aren't always as well trained.
If however you have skills or seek a skilled Jaguar trained Mechanic ownership can be fun and not horribly expensive..
frenchyd wrote: Apparently you don't read the trade magazines.. Jaguar was up for sale and deeply in debt to GM For decades worth of transmissions etc.. GM was doing it's due diligence with plans to buy Jaguar.. Upon looking it over they discovered a lot of tooling that existed in the 1940's and was past worn out. The only thing new was the 4.0 aluminum block 4 valve head in line six with a fantastic reliability record. Rather than walk away GM bought the engine and tooling Just before Ford Swooped in with a fantastic Bid. GM brought the engine here and Americanized it.. That is they sourced American components and increased it to 4.2 from the 4.0 it was at in Jaguar's hands. The ancient 4.2 had nothing to do with the engine that eventually wound up in GM's SUV's such as the Trailblazer/Envoy etc..
Take a look at the 2 engines. The blocks are clearly different. The cylinders on the Atlas stand upright, while the AJ16 is a slant 6. The stroke of the 4.0 AJ16 vs 4.2 Atlas does match and the bore is only slightly different, but that and both being a DOHC aluminum I6 is all the similarity I can find.
Also, the creation of the Atlas engine and the discontinuation of the AJ16 both happened long after Ford bought Jaguar (Ford purchase was 1988, Jaguar was building AJ6 / AJ16 engines through 1997 and the Atlas wasn't in production until 2002).
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