V12 v Straight 6
#1
#2
Join Date: Jul 2010
Location: Austin tx and Daytona FL.
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leo_denmark (09-03-2019)
#3
#4
It's not the engine, it's the electrics that let down Jaguar motors. And now, thanks to the internet and communities such as this, all the V12 and I6 weak spots have been well documented. In other words:
- find a good example
- do preventive maintenance on the things that are known to go bad
- drive it like you stole it
- ??
- profit
For me, it's 12 or go home. Not knocking the 6 though - many guys here swear by them, particularly when mated to a manual transmission. But still VEE TWELVE, Son!!!!!
- find a good example
- do preventive maintenance on the things that are known to go bad
- drive it like you stole it
- ??
- profit
For me, it's 12 or go home. Not knocking the 6 though - many guys here swear by them, particularly when mated to a manual transmission. But still VEE TWELVE, Son!!!!!
Last edited by Flint Ironstag; 06-03-2013 at 06:00 PM. Reason: grammar and clarification
The following 2 users liked this post by Flint Ironstag:
Mguar (01-01-2020),
Pawsnclaws (11-05-2020)
#5
As said.
The V12 is "special", as is the ownership.
Preventative maintenance is the HUGE key word here.
Followed very quickly by "catch up" maintenance. Now this one is usually what sorts the wanna be's from the real deal.
My V12's have been daily drivers, and traversed our "small" island many, many times, and just will not stop until turned off at the key.
The PreHE 1976 XJ12 is nudging 505000kms and the engine itself is untouched. OK, most of the add ons have had attention, but nothing major springs to mind.
Also as said, DO YOUR HOMEWORK, and please LEAVE EMOTION AT HOME.
The V12 is "special", as is the ownership.
Preventative maintenance is the HUGE key word here.
Followed very quickly by "catch up" maintenance. Now this one is usually what sorts the wanna be's from the real deal.
My V12's have been daily drivers, and traversed our "small" island many, many times, and just will not stop until turned off at the key.
The PreHE 1976 XJ12 is nudging 505000kms and the engine itself is untouched. OK, most of the add ons have had attention, but nothing major springs to mind.
Also as said, DO YOUR HOMEWORK, and please LEAVE EMOTION AT HOME.
Last edited by Grant Francis; 06-04-2013 at 02:56 AM.
#6
Join Date: Mar 2008
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Any red-blooded car guy needs to own a V12 at least once in his life.
It really helps if you like to tinker
But.....
Keep your options open. Buy the "right car". If it happens to be a V12, so be it. Likewise for the 6-cylinder. XJSs are neat cars either way.
Beware of "iffy" examples at a bargain price. There's is nothing more expensive than a cheap Jag.
Cheers
DD
It really helps if you like to tinker
But.....
Keep your options open. Buy the "right car". If it happens to be a V12, so be it. Likewise for the 6-cylinder. XJSs are neat cars either way.
Beware of "iffy" examples at a bargain price. There's is nothing more expensive than a cheap Jag.
Cheers
DD
#7
Hello Marcus,
You mentioned that you've been "advised" against the V12. Could you elaborate on what concerns in particular those that passed along this advice had? I'm not suggesting that it/they are "wrong", but while the V12 does have its problems, the balance of of those are fairly easily corrected. With the advice you find here, Kirby Palm's book and info from some of the other good web sites on the V12, it's delightful what you can do with it.
Be it V12 or 6, welcome aboard!
John
1987 XJ-S V12, 62,000 miles
You mentioned that you've been "advised" against the V12. Could you elaborate on what concerns in particular those that passed along this advice had? I'm not suggesting that it/they are "wrong", but while the V12 does have its problems, the balance of of those are fairly easily corrected. With the advice you find here, Kirby Palm's book and info from some of the other good web sites on the V12, it's delightful what you can do with it.
Be it V12 or 6, welcome aboard!
John
1987 XJ-S V12, 62,000 miles
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#8
You've had a lot of good advice so far. Not much to add, apart from the fact that any XJS is at least 17 years old, so you could easily buy a 6 that turned into much more trouble than a 12. It's got a lot more to do with the cars history and previous owners at this age.
I did a very rough post count on issues here on the forum over the past 1 month....... of all the "trouble" posts, meaning someone has something they need help fixing, actually more were from 6s than 12s. This could be attributed to there being more 6s than 12s in general though.
To be honest, I think the V12 issues list is relatively short, however, each item can go wrong in a big way, so it pays to know what you're getting yourself in to.
1) Overheating --> will kill the engine. There are A LOT of posts on here about overheating. I have a very lengthy one myself. But I would guess that 80% of the issues are caused by a blocked radiator and/or fans not working properly. Things that are relatively easy to fix if you know your way around a tool box
2) Fuel fires from failed injector hoses. Only affects the earlier cars on your list. 92 facelift and up cars don't have this issue. Even if you buy an older 90 car with the fuel hoses, it's an easy job to switch them out.
3) Wiring in the engine "V" gets toasty and cooked after a while. You can either buy an expensive replacement harness, or do what a lot of us here have done and make your own. It's a straightforward job and pretty rewarding to do.
4) Marelli ignition failures followed by cat converter fires. A peculiar quirk, but there are a lot of preventive measures that you can take, all are well documented. In the end it could still happen as the failure mechanisms are varied, but just knowing that it could happen and reacting correctly (stop the car immediately, don't try to "limp" home, call a tow truck) will help you avoid the worst.
If I had my choice I'd try and get a 6.0 V12 (93.5MY and up) Those cars are the last of the line and have a few nice enhancements (4 speed tranny for example).
So, in summary, definitely do not rule out a V12. The fact that when it is cranking it sounds like you have no compression going on because it is just turbine smooth is fun. The fact that it makes my V8 feel "rough" is fun. The fact that they can pull easily from 10mph in top (3rd gear) and continue on to >140mph is also quite fun :-)
We are here to help you when you narrow your choices down to some actual cars.
I did a very rough post count on issues here on the forum over the past 1 month....... of all the "trouble" posts, meaning someone has something they need help fixing, actually more were from 6s than 12s. This could be attributed to there being more 6s than 12s in general though.
To be honest, I think the V12 issues list is relatively short, however, each item can go wrong in a big way, so it pays to know what you're getting yourself in to.
1) Overheating --> will kill the engine. There are A LOT of posts on here about overheating. I have a very lengthy one myself. But I would guess that 80% of the issues are caused by a blocked radiator and/or fans not working properly. Things that are relatively easy to fix if you know your way around a tool box
2) Fuel fires from failed injector hoses. Only affects the earlier cars on your list. 92 facelift and up cars don't have this issue. Even if you buy an older 90 car with the fuel hoses, it's an easy job to switch them out.
3) Wiring in the engine "V" gets toasty and cooked after a while. You can either buy an expensive replacement harness, or do what a lot of us here have done and make your own. It's a straightforward job and pretty rewarding to do.
4) Marelli ignition failures followed by cat converter fires. A peculiar quirk, but there are a lot of preventive measures that you can take, all are well documented. In the end it could still happen as the failure mechanisms are varied, but just knowing that it could happen and reacting correctly (stop the car immediately, don't try to "limp" home, call a tow truck) will help you avoid the worst.
If I had my choice I'd try and get a 6.0 V12 (93.5MY and up) Those cars are the last of the line and have a few nice enhancements (4 speed tranny for example).
So, in summary, definitely do not rule out a V12. The fact that when it is cranking it sounds like you have no compression going on because it is just turbine smooth is fun. The fact that it makes my V8 feel "rough" is fun. The fact that they can pull easily from 10mph in top (3rd gear) and continue on to >140mph is also quite fun :-)
We are here to help you when you narrow your choices down to some actual cars.
Last edited by Sarc; 06-03-2013 at 11:04 PM.
#9
#10
Yes you do need to know a little bit, for example the distributor needs oil to operate properly. It’s about on page 65 of the owners manual.
Failure to use a few drops of oil will cause power loss due to overheating. Because of the high torque and smoothness few drivers will be able to feel it.
It was also early days of electronic fuel injection. While Jaguar used 3 Bosch units and batch fired the injectors. Few really understood.
As I said those were the days of Car- B - Que’s I had a Chevy Blazer that went up in flames. Melted the wheels off leaving little more than puddles
the Six came after all that development was done. Thus earning a reputation that all Jaguars by then actually had. Once Jaguar had development funds provided by Ford they became extremely reliable based on JD Powell ratings. earning
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