RE: Jaguar XJ-S V12 | The Brave Pill
Discussion
Give the relatively high compression ratio of the V12 (even though in many iterations it was lowered for the US market) I imagine running on 86 - 89 AKI could well cause a lot of pre-detonation.
300bhp is right though, as much as I'm aware of the widespread reputation for dropping valve seats in the US they simply aren't known for it in the UK. The US market does seem to have much higher expectations of stone axe reliability with little maintenance beyond oil changes (seemingly every 500 yards) though and the V12 does require that you pre-emptively keep the ignition components and cooling system in tip top condition if you don't want trouble. They may also have sold a lot more V12s there?
As I said earlier in the thread at the time the V12 was pushing the limits of what was possible in terms of EFI and ignition control, and it generated vast amounts of waste heat. It doesn't suffer neglect well.
300bhp is right though, as much as I'm aware of the widespread reputation for dropping valve seats in the US they simply aren't known for it in the UK. The US market does seem to have much higher expectations of stone axe reliability with little maintenance beyond oil changes (seemingly every 500 yards) though and the V12 does require that you pre-emptively keep the ignition components and cooling system in tip top condition if you don't want trouble. They may also have sold a lot more V12s there?
As I said earlier in the thread at the time the V12 was pushing the limits of what was possible in terms of EFI and ignition control, and it generated vast amounts of waste heat. It doesn't suffer neglect well.
I wonder if with the V12 being the most expensive model, that the majority of sales in the US were in the most affluent part of the US which would be California? In California it tends to be a little warmer than in the UK and as such the average V12 in the US just ran hotter and thus a different set of issues transpired?
Plus, in the UK, maybe again due to weather, the body fell off the car asnpowdered iron oxide before the engine had a chance to wear itself out?
Plus, in the UK, maybe again due to weather, the body fell off the car asnpowdered iron oxide before the engine had a chance to wear itself out?
DonkeyApple said:
I wonder if with the V12 being the most expensive model, that the majority of sales in the US were in the most affluent part of the US which would be California? In California it tends to be a little warmer than in the UK and as such the average V12 in the US just ran hotter and thus a different set of issues transpired?
Plus, in the UK, maybe again due to weather, the body fell off the car asnpowdered iron oxide before the engine had a chance to wear itself out?
No, the US has affluent people everywhere and these cars sold in numbers anywhere where foreign cars sold in numbers as it's the biggest market for them. Issues were not limited to dropped valves. Distributor issues, leaky fuel rails and ignition system failures would disable these cars and in many cases cause them to catch fire. Plus, in the UK, maybe again due to weather, the body fell off the car asnpowdered iron oxide before the engine had a chance to wear itself out?
This was before the LS motors and regular SBC motors with carbs and mechanical fuel pumps can get dropped in with relative ease.
alabbasi said:
Fuel has nothing to do with it. US cars have lower compression engines set up for US standards and the ignition is timed for it.
I'm afraid it does have something to do with it. An engine will be setup to require a minimum amount of octane to avoid knock/pre-det. Running a lower octane, especially in a hot climate could well result in running and heat issues. Which in turn could contribute to other failures caused or contributed by this.You own some V12's in the USA. Does the owners handbook or filler cap state a minimum octane rating? I'm willing to be it isn't 87 octane.
alabbasi said:
Not as smooth for sure but it gives it the performance it should have had and costs next to zero to fix. More importantly, it's kept a bunch of otherwise nice cars from being dismantled
That's why I would use either an RB25/26 or a 2JZ. The smoothness (almost) of the V12, but smaller, lighter, more reliable, and much more power. Doesn't have to have a silly exhaust or anything, before someone says it! alabbasi said:
I currently own 3 V12 Jags and a 6 cylinder. While I'm enthusiastic about the V12. I'm also a pragmatist. After reading some of the posts here. I'm wondering how many who posted have actually owned a V12 Jaguar.
Your “enthusiasm” for the V12 doesn’t really come across too well in your posts. My dad had two (carb E Type and injected HE XJ-S). Both long in the tooth when he bought them, but neither engine gave any trouble over many years of ownership. Other issues, yes, but the engines themselves never.Edited by alabbasi on Tuesday 17th September 23:57
LotusOmega375D said:
Your “enthusiasm” for the V12 doesn’t really come across too well in your posts
That's because I work on my own cars. I also own a Mercedes Benz 300SEL 6.3 which I love and hate at the same time for same reasons. Lots of great qualities but a pain in the rear to work on and everything is expensive. Edited by alabbasi on Wednesday 18th September 19:09
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2...
No but this is crying out to be rescued by somebody
No but this is crying out to be rescued by somebody
I see your XJ-S and raise you a factory pink XJ12 Series 1.
https://www.ebay.co.uk/itm/Jaguar-XJ12-S1/27430989...
https://www.ebay.co.uk/itm/Jaguar-XJ12-S1/27430989...
Reciprocating mass said:
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2...
No but this is crying out to be rescued by somebody
Wow.No but this is crying out to be rescued by somebody
Reciprocating mass said:
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2...
No but this is crying out to be rescued by somebody
A seventies manual pre he xjs is Britain's Ferrari Daytona in my slightly skewed eyes!!No but this is crying out to be rescued by somebody
I had a gold 5.3 V12.
British Leyland build quality meant being on a par with the rest of the BL range. I remember the old Allegro I also had at the time had better paint quality.
The Jag had wet footwells and numerous oil leaks. It really wasn't worth spending on it. It got broken for parts and the rest went in the masher..
British Leyland build quality meant being on a par with the rest of the BL range. I remember the old Allegro I also had at the time had better paint quality.
The Jag had wet footwells and numerous oil leaks. It really wasn't worth spending on it. It got broken for parts and the rest went in the masher..
Reciprocating mass said:
That pink interior is horrid but I still want it 
Edited by Reciprocating mass on Sunday 22 March 12:22
With all the negativity regarding these i wonder how this car will achieve this high price, under 20k might be possible soon!
https://www.carandclassic.co.uk/car/C1136345
Edited by cayman-black on Sunday 22 March 17:40
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