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aussie74

Help with V12 conversion

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Hi there everyone,

 

I have owned my Z for about 3 years now, drove it for 2 years until my sister destroyed the front end and now it is completely stripped...

 

I have currently got 2 engines, the original 2.6 and a 2.8, both with gearboxes and both fully dressed. However, in its current state i have been thinking about converting it to a V12 with a supra 5 speed and have access to a pre HE jaguar V12. i have had many people tell me that the Jag engine is unreliable and was wondering if anyone had any experience with these engines that could tell me the true story???

 

also, for Dot i know you have done this conversion how do you find the reliability of the Jag V12? Also, have you found that the extra weight of the V12 has been detrimental to the handling of you car?

 

Cheers,

Mark Browne

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Have you noticed when you drive past petrol stations that petrol now costs a lot more than it did a year ago?

My theory is that the price went up due to the shortage caused by Jaguar V12s drinking far more than their fair share.:wc:

There are better, lighter, more powerful, more economical engines out there.

First clue ,None of them made in England!

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I realise this, but i want a V12. That leaves me with BMW (too expensive), Nissan and Toyota both did a V12 I believe (too hard to find), Lamborghini (too expensive), Ferrari (too expensive) you get the picture.

 

Jaguar V12 complete and running $600 (from my dad...).

 

Does anyone with any experience with jag motors have anything to say?

 

fuel prices don't really concern me, this will only be a weekend car...

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If you plan on having it registered the first thing you have to do is visit the DOTARS site and see what you need to comply with. Then take your plans to an Authorising Engineer and obtain an 'in-principle' agreement. It can be done (vehicle mods generally I mean, not necessarily this one) but take your time and think the project through in the first place. It is no good spending time, effort and money for something that will never get registered; e-bay is chock-a-block with examples of projects that will never be registered. Good luck.

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I realise this, but i want a V12. That leaves me with BMW (too expensive), Nissan and Toyota both did a V12 I believe (too hard to find), Lamborghini (too expensive), Ferrari (too expensive) you get the picture.

 

 

04.jpg

 

mercedes?

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Sheesh - here in the US for V12 engines, the Jag is super cheap (but heavy), BMW is cheap (but depending how you proceed gets very pricey), Mercedes seems to hold value (complete engines go mostly over $5000) Next in value is probably Aston Martin, then Ferrari and Lambo. We almost never even see anything on the Japanese V12's, Occasionally I'll see a VW "W12"

 

Another price consideration is if you want a manual trans. Most Ferrari an Lambo were manual, but almost all of the Lambos are for mid engine rear drive. Best option is Jag on cheaper end, Aston on pricey end for manual trans as the BMW Getrag is rare and pricey (retail $6000) Aston uses the much more common T56. To put the T56 on any of the others will require custom Bellhousing ($1000+) and custom Flywheel (another $1000)

 

Mercedes didn't come with manual trans, and I doubt the VW or japanese ones do either

 

One more factor to deal with is width.

BMW fits, Aston tight but fits, Jag fits, the Japanese ones I don't know, the Early Ferrari (from 1960's) fits but cost $30,000 for even a parts engine, the late 60's through early 80's Ferrari and Lambo, the W12 and all the Mercedes V12's are too wide unless you go to a tube front end and do away with the stock suspension. Most of these will also likely require you to make a new front crossmember (not the Jag though).

 

If you use an earlier engine with carbs you'll save a little money, if using EFI then you need either the original computer/s and a harness to wire it or the skill to make 2 Megasquirt systems or $3000-$6000 for engine computers.

Hope this helps.

Chelle

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Hmmm, cheap buy for the engine, but have you priced parts? I had an 88' Jag XJS. Loved driving it, hated working on it. Damned starter was $400 and took like 6 hours to replace. Don't go Jag. Don't go V12 in all honesty.

Sounds like you were lucky, at least you got out before the steering rack died.

Boy from Oz's advice good, check with an engineer, Queensland is probably the only state you would be able to do it, and the draft plan for Australia wide standardisation of the rules could be taken up sometime soon (this was on the DOTARS site but could not find it when I looked today.)

 

 

Aussie 74, just noticed you are talking about a pre HE,petrol wise, better alter your plan from a weekend driver to a leap year driver.

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Its never a good idea to approach a conversion from the situation of having a particular engine available, cheap. Then trying to justify why that particular engine is suitable.

 

The best approach is to define what you want from a conversion then look at what will do what you want.

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Guest 250gto_au

I notice your from Aus as well...

Just a note. I have a 240z ferrari 250GTO replica with a 6.7ltr V8 Pontiac and trust me that was hard enough to get registered in QLD. So talk to a reliable engineer first, would hate to see you do it and then get knocked back by the RTA.

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okay...lets see...ya wan to put a v12 jag in your car sounds ..i dont know how much milage on this engine but here are some tips to make it worth your time,,you see jaguar engines tend to over heat for the simplest reasones...there for,,your gona have to fix this,,

ya can do that by adding a higher capacity raidiator...remove the thermostats..add an oil cooler for the engine..oh dont pick it out of the junkyard.get a hight capacity one with an electrick pump....

 

if the engine needs to be rebuilt then it has to,,try to add anything else that helps preventing detonation as these blocks overheat and that was the main reason why they were discontinued..mega squirt it.do not carb it..the more precise yo do this,,the more happy engine you have,,,oh if the engine over heats it CONsumes oil more than gas,,hehehe,,sorry but alot to be done to fix this...atleast i said go for it..lol

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I did not read all the posts above.

I can tell you what I know from 11 years of working on Jaguars for a living.

The Jag V12 is not worth the time and effort because of the cost, few design flaws and the weight of the engine. The engine was designed on the racetrack and the ones they built for racing are torn down often, the ones built for the street were built a lot like the ones built for the track but we don't rip down the ones in our street cars as often as the racers do and there lies a problem. I have had to work on countless V12s and 99.9% of them had the heads seized to the block, this was not fun when doing headgaskets. They don't make enough power in stock form to justify the swap the way I see it, now this does not mean they can't be modded beause there's some guys around the world that are modding them and getting some good power but you can only imagine the $$ being dumped into them. They are VERY HEAVY motors and also when running they put off some serious heat, these are factors that you should consider. I'm not telling you what to do because by al means follow your heart but have your heart consult your bank account.

Ohh yeah, let me know (VIA email is the best way to contact me) if you need any tech info, I still have all my diagrams and some tech books on the V12s even though I been away from Jaguar for the past 3-4 years...;)

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Hi there everyone,

 

I have owned my Z for about 3 years now, drove it for 2 years until my sister destroyed the front end and now it is completely stripped...

 

I have currently got 2 engines, the original 2.6 and a 2.8, both with gearboxes and both fully dressed. However, in its current state i have been thinking about converting it to a V12 with a supra 5 speed and have access to a pre HE jaguar V12. i have had many people tell me that the Jag engine is unreliable and was wondering if anyone had any experience with these engines that could tell me the true story???

 

also, for Dot i know you have done this conversion how do you find the reliability of the Jag V12? Also, have you found that the extra weight of the V12 has been detrimental to the handling of you car?

 

Cheers,

Mark Browne

 

Hi Mark;

 

Sorry for the delay

 

The nice thing about the jag build up is the fact that you can pick and chose the parts that work and toss the stuff that doesn’t. If it has lucas written on it …well you know all about the prince of darkness. The only thing that is left on mine with lucas on it is the dizzy cap. I can’t get around it.

 

The fuel injection is passable but after market, home built equipment on this sight is better. The real problem is the ignition system. Replace it with something hi performance. The distributor advance is known for seizing in it’s own grease. Go check yours now. I’ll bet it is stuck. This in turn messes up the rest of the motor. The dropped valve seat in # 6b is the most notable result. It is such a small thing that has given the motor such a bad reputation.

 

Over heating is cured by placing bleed lines on top of the thermostat housing. It will never run hot again.

 

I just laugh at the guys telling me the motor is a dog or unreliable and expensive. I’ve driven mine like I stole it for the past 7 years, knowing full well I have a spare V12 in the garage that cost me a case of beer. The reason for my delayed reply is that I actually drive this car and have little time for farting around defending my choice of drive train.

 

Do the Jag Mark, if for just the sound alone.

 

And the rest of you guys, if you’re in Toronto look me up… we’ll go for a ride.

 

Ps; this guy wrote the book

http://www.nettally.com/palmk/jaguar.html

 

 

 

V12Z03.jpg

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