an article about a Lexus , car mag. one just made 1 million miles on original engine,speedo reads 999,999, miles ,5 owners, car was in the junkyard dents and bangs all over it, no paint left, interior ROUGH!
but engine still ran good , of course those Japanese dont know much about cars????LOL>
ron

Why are you trolling on a forum that is almost exclusively for the V12s when clearly you only have eyes for the Chevy? The V12 was one of the most innovative engines in its day and when made for the xjs was de-tuned. It wasnt meant for racing and yet it still had more power than your V8 corvette, even after you’d taken it home and put different carbs on it! The main slug in the V12 was the American auto box! I notice that you failed to mention the Listers that were chucking out 750bhp in street mod or the Lynx Performers. Doesn’t this fit in with your argument? As to it being dead do you not see the supercars with V12s in them that are still being made? Keep your boring and common vulgar V8s and I’ll stick with my V12!

Who are you replying to?


Cheers
DD

The 85 V12 XJS won Bathurst in 1985, with 3 cars finishing in the top 4.This was against the Group C V8 race cars of the day. Look it up on Youtube.

Long live the XJS :)

When I started reading this forum from page 220 to page 1, there were a lot of discussion over the V8 conversion from the V12. There hasn't been that discussion for quite a while until this thread reappeared.

I remember the 1985 race, also remember the 1984 race which wasn't as successful.

I remember the first XJS I saw (in 1993), not sure how old it was at the time, but it was a complete rust bucket. Remember seeing under the bonnet and just staring in wonder (and then closing the lid).
I remember the owner wanting $5000 for it, knowing how much they cost new, that was a massive depreciation factor

Even with modern information availability like this forum, u-tube, etc, the V12 can still beat the average guy,

If placing a V8 in one of these beautiful cars means that it keeps them out of the scrape yard or parted out, I am in full support of it

Just my opinion

Cheers
Steve

While I agree with your statement and sentiment. Let us not forget that in the decades since our V12’s were made, there have been vast improvements to operation of those Chevy V8’s.
Not so great I’d ever consider replacing my V12’s with the mundane V8 but rather as a goal as to what could be done to our V12’s.
If there were a modern ECM for our V12’s that was simply a plug and play sorta swap wouldn’t you eagerly buy one?

This is how I look at it...

Jags are awesome, No doubt about it. Once you have owned a good one, you get hooked.

Unfortunately the Jaguar engines require babying and constant watching which is fine for the serious enthusiasts who love tampering and having that feeling of owning something special and cool. I happen to be one of those owners hence the '84 XJS HE V12 I have in the garage. I love driving it and I love working on it, so long as it stays more maintenance based than constant break-down based, which luckily I am not having at this point. So long as this stays the norm, I will be happy.

On the other foot, I seriously have no issue with folks that want a reliable, V8 swapped engine into their Jaguar. The reliability factor and simple repair options from hugely massed produced engine parts makes this an extremely viable option to have a nice old classic car with high power and reliability. In my opinion a standard old SBC 350 carby option is probably getting a bit long in the tooth, but depending on a tighter budget, still a decent option in many cases.

Everyone has their choices and so long as a V8 swap is done professionally and safely, I see no reason for anybody to get too serious with slagging off these V8 swapped options. If people really can't see "any" benefit from this, then you really are not thinking deeply enough. If getting high power and reliability, economically with a V8 swap, then they will certainly drive their Jags more often and get more enjoyment rather than their vehicles sitting in the garage waiting for parts from the UK to turn up, (Like me at the moment waiting for my AJ6 package to arrive which has now been 14 weeks and still a few weeks away apparently!!!)

From my personal experience and along with a huge amount of research and serious pricing options looked at, V12 power upgrades simply cost far too much money, which is so easy to achieve otherwise with the GM V8 platform. And let's get real here... Engines with 450 HP + are much more fun to drive and achieving this with the V12 is just too hard to achieve (Financially).
THIS IS THE MAIN STICKING POINT.

Open your minds... Jags are awesome whether you have your original engine or your swapped V8. (So long as you do it properly haha!)

Mundane... Carby 350 SBC chev, maybe. Yes!

Late model, high power, injected LS or LT V8, mundane? Not so sure about that one!

Otherwise, V12 ECM options - absolutely, I would!

Well, my S3 did not come with a V12 to me anyway. Intriguing to be sure. I recall seeing an S3 at a Hardware and garden store decades ago, well before mine came aboard. External beauty. No opportunity to look under the bonnet. Did it make an impression., Absolutely.

Well, I've written of the demise of my "mere" DOHC 6 . I'll not repeat.

The LT1 that replaced the 6 is not perfect. But, it became legal in 2006. Passed special referee inspection.

I still delight in looking at it and driving it. Had I been able to "fix" the serious issues on DOHC, I' d
enjoy it... An intriguing engine, no doubt about it.. The V12, even more so...

Carl..

:

I believe I have as open a mind as anyone. I’ve owned Chevy’s most of my life. I’ve also raced Jaguars most of my life.
My last Chevy went 371,000 + miles ( 20 years) before rust made it unsafe. Very good service. But I raced my BlackJack ( Jaguar Special) for decades longer with never an engine related failure. When sold, it raced for more years with the same engine. ( it’s currently in the Packard museum )
When I built my XKE V12’ I assumed I would need plenty of spares and began accumulating them. Out. Of more than 50 “junk” motors only 2 had internal damage. One caused by a loose oil filter. With the driver ignoring all warning signs.
The other was caused by leaves between the A/C and radiator again with the driver ignoring all signs.
Many so called junk motors had simple vacuum leaks caused by old rubber hoses or distributors frozen due to failure to read the owners manual where it says to oil the distributor.

The Quality of parts in a Jaguar vastly exceeds those of Chevy. With brilliant engineering. In fact stock parts in Jaguars often exceed the best comparable parts in Chevy Race car engines!!!!

Now Jaguars do fall short in some aspects of reliability. HVAC for one, wiring, for another. Rubber products for a third.
Swapping the less powerful Chevy V8 does nothing to improve that!

As for power.
You do understand the difference between the old Gross horsepower and modern Net don’t you?
A 1980 Jaguar V12’ makes 262 DIN HORSEPOWER ( about 275 SAE net. ) the same Chevy 350 in 1980 made 160 SAE Net. That is 110 horsepower less

in Fact Corvette didn’t make as much horsepower until about 1986 or so. When finally it’s more modern Fuel injection caught up. I’ll have to do some research to figure out when Corvette finally caught up to Jaguar’s Torque.

As for making more than stock power. Unfortunately a lot of hot rod products claim unreal horsepower gains.. both Jaguar and Chevy.

CORVETTE has an advantage over Jaguar though. Its’s lighter. Jaguar weighs in at over 4600 pounds. It’s designed to be a continental cruiser not a race car. In an attempt to get better gas mileage most Jaguars are saddled with a 2:88 final drive ratio.

IMO, the best reason for a V8 is easy access to lots more power. And there's nothing wrong with that.

The reliability/upkeep arguments are not as compelling, IMO. But I won't get into the weeds on that :)

I'm as much of a Jag nut as anyone here. But, at the end of the day, a Jaguar is still just a car. It doesn't have an actual heartbeat. A Jaguar isn't an altar we must kneel before. The important thing is that we all get enjoyment out of owning them. There are many ways to do so. It's a big hobby with lots of room

Cheers
DD

Mguar, I was not pointing any fingers... Just generalizing.

Yes I do understand the differences, but as I have mentioned, I am not really a fan of the Carbed SBC especially when there are no power gains. Would rather have the V12.

The LSA will be leaps and bound's more powerful then my V12 XJS and this is my goal.

There is simply no comparison, regardless of the weight of the car. The LSA will blow the XJS off the planet.

319 foot pounds v 560 foot pounds for starters...



Craig

The Chevy small block stopped production about the same time Jaguar stopped making the V12 ‘s That was more than 2 decades ago.
Chevy still has pushrods and rocker Arms but the LS has to compete against the Jaguar V8. Pushrods and rocker arms against DOHC 4 valves. YEH chevy has a supercharger just like Jaguar.

To make a Chevy look pretty, you have to put a lot of aluminum stuff on.
To make a Jaguar V12 pretty, clean and polish it.

also be aware that today there are some full size 4 cylinder turbo cars that would run away from a factory V12 XJS!

with encredable MPG also! and out handle it while its doin it!
ron

MG when you gonna show us your up and running Jag V12 , seein as a lot of talk and NO action?

maybe we could setup a race somewhere,, my XJS VS your car, winner takes others car and title!!

just like old time racing!
ron

If you measure progress by numbers you are absolutely right, but don’t forget the old 4 cylinder Offy was making 1000 horsepower 5 decades ago.

On the other hand todays cars don’t stir my soul as much as that elegant hunk of Aluminum does.

Old time racing? I’ve never raced for anything more than the pleasure of gentlemen dicing.
Should you choose to I’d enjoy meeting you at the 4 mile long track at Elkhart Lake and see how you enjoy real Wheel to wheel racing. Fair warning, that track is absolutely brutal on brakes, When the Indy car teams arrive they do so with the biggest brake cooling scoops they have.

Nowadays a V6 Honda Accord for Grandpa will outrun many of the high-performance cars of not that long ago. And today's high performance cars that you buy off the showroom floor are as fast a tracks cars of yesterday.

I think the base model Corvette is nowadays running the 1/4 mile in, what? High 11s ?

Cheers
DD

Put it in context. The First XJS is 44 years old with the first V12’s another 4 on top of that. So Compare the V12’s to engines of the mid 1920’s.

Yeah, but we all know that what's important on the track often doesn't translate into something meaningful for an average hobbyist using his car on the street.

A hapless V12 owner with dropped valve seats isn't gonna take any comfort whatsoever in knowing that his crank pins are larger than the crank pins used on a SBC..... or that he has 54 studs instead of 20 bolts holding the crankshaft in place

And many a lumper has discovered the a SBC alone doesn't guarantee a happy Jaguar ownership experience. They still spend lots of time fussing with their Jags, and the really nice conversions are neither cheap nor quick. Lots of labor hours involved.

With bit of patience and willingness to learn the Jag V12 can be a perfectly reliable engine. Heck, my daily driver is a V12 Jag. The engine is fine. I've used Jags as daily drivers for 22 years and never been on the back of a tow truck.

A SBC, even with (oh my Gawd!) old fashioned pushrods can be a really good alternative and one that has proven to make a lot of Jag owners happy.....even if a side-by-side spec-sheet comparison does't read as impressively. In the grand scheme of things the SBC is a marvel in actual use and in automotive history.

Cheers
DD