I am planning to have built a replica of the XJ-13 and wondered what suggestions folks might have for the power train if I choose to use an injected V-12 Jag motor. I am new to the Jag world so please understand I don't necessarily know all the right questions to ask.

Some have suggested forgetting originality and going with a crate motor from another manf. (e.g. a GM LS-3 engine). This is obviously anathema to others. I am considering that approach but also want to look at what the options are for using a Jag V-12 or perhaps another Jag engine type.

No idea where to find such engines, what transmission and clutch to pair with them, what to budget for cost, etc. Any thoughts welcome. Thx in advance.

 

Welcome to the forum spinsky,

That sounds a hugely desirable although very costly project.

Probably the best forum for advice on the V12 Jaguar engines has to be XJS - Jaguar Forums - Jaguar Enthusiasts Forum for the XJS models.

The guys there will be able to advise on the various stages of development of the Jaguar V12 unit. They should also have a handle on what has already been done and what could be possible.

Good luck and keep us up-to-date with progress.

Graham

 

Thx Graham--I'll check out that forum. I appreciate the tip. Till next time,
Scott

 

Hi Scott,
If you are serious about building this replica of probably one of the most beautiful and exotic machines ever built.
PLEASE don't use the most common of all engines in it!
SBC stands for Small Boring Chevy.
No offense to anyone out there, as there is noting at all wrong with the engines as they are great, but over-used in a wholesale manner.
This machine needs to be treated with something special.
You can go to the '86 V12 HE engine EFI 12 stack thread and join in as it's easier than jumping around, and I could give you some suggestions for what might be more acceptable for it.
The trick is to mate it with the proper trans I would say would be the major concern.
Fran Olson (FOX)

 

where is the body coming from?

 

Hi all. Thanks for the posts in reply to mine. In response:

1. The car is being build by Rare Car Replicas in Detroit.

2 As for the Jag V-12 vs. crate motor issue, I have spent some time trying to find info on the V-12 as a potential project. Although I have not read every thread, I am sure, frankly what I have read is disheartening. All the posts I seem to find describe only frustration, grief or worse.

Among V-12 owners, I detect a very common reaction to run for the doors, as evidenced by the fact that conversions to non-Jag and non-V-12 motors seem to be more than commonplace. This is true to the degree that some companies even specialize in selling kits for this sole purpose. (I have never heard of any company that can make a living selling kits to convert Ferraris to Ford or Chevy power; same for Maseratis, Lambos, Alfas, etc. Most owners of respected marques would die before converting to a US-mass produced engine. No disrespect here, but Jaguar owners seem to do so with no second thought. This gives me pause. How could it not?!?)

Consider this: I spoke to one group that sells reconditioned Jag engines for a living and told them what I am interested in doing. Their reaction: "Get a GM crate motor instead." This was a Jag engine rebuilder!

Another specialty shop said they could provide a rebuilt motor, but at a cost that would be ~3X that of a brand new GM V-8. By the time I get the tranny, EFI, etc, I'll be looking at over $30k PLUS a boatload more for installation.

Even the group that is building the car for me recommends strongly against trying to find and install a Jag engine, despite the considerations of authenticity.

So what can explain this apparently universal dread of the Jag V-12 engine configuration? Obviously there were quite a few units produced so rarity should not be the biggest problem. Reliability issues clearly predominate as the problem for most folks, which item also implicates cost obviously since frequent repair and maintenance seem to be inescapable.

At the end of the day, if even a Jag engine rebuilder doesn't get excited about the prospect of selling me a V-12 motor for this car, what am I doing to myself to try to go down this road?

I completely understand and appreciate the opinions of those who find it unthinkable to contemplate a US-made V-8 in this replica. I do not disagree in spirit. But I am the one who has to deal with the consequences of whatever unit is selected. Cost is surely one criterion, but not the only one. Mainly, I want to get the thing built as soon as I can, get it on the road under its own power (by itself, not on a flatbed), and have it stay reliably there. Can this happen with a Jaguar V-12 engine? No one has yet convinced me so.

 

Hi Again,
OK, first, if you don't use a V12, it really isn't what you are trying to accomplish, and I'm sure you will never be happy with it.
I see no real problem in doing it right.
I have no idea what the car itself is going to cost, but why bother if it isn't what you set out to do?
Sure the engine will be a SHOC not DOHC, but it would be at least a Jag 12.

Second. if someone was going to put a GM engine in it, what would they use for a transaxle?

I really don't see a problem with the engine itself as they are fine.
The only real problem is the operating systems, which seem to be the issues with all the Jag owner that toss the engines for something common.
I pretty much have that taken care of.
If you go to the other site I've been posting you'll see what I'm doing with the V12.
I'm taking a very simple approach, and have stripped everything off the engine, and starting over.
If you want, I can handle the engine part of this for you.
I just need to know what you want as an end result.
Most of the people who have me make it 'shiny', but I can make it look like means business with out the shine.
Fran

 

Hi Scott,
I hadn't seen any reply to my post on the engine for your car.
You can call if you want to the shop and we can chat about what the possibilities for that are if you like.
If you want you can go to my website and get the # there.
Everything I have done during my car career has been on the unusual side if you have seen some of my posts, and will be glad to help you out.
(I might even have a 4 cam V12 for you to use).
Fran from FOX Engineering Co.

 

I am normally all for using a modern GM LS v8 as it has loads of power, reliability and good fuel economy but given this particular model of Jaguar where the engine is visible and not covered, maybe instead of a Jaguar V12, what about a Ferrari V12? It would be cool to show the V12 stacks as showing a V8 set of carbs would be a quick giveaway it is not a real Jag, if the Ferrari V12 is more reliable? I just suggest that as other brands of exotics used the Ferrari V12 and I never heard of any exotic choosing the Jag V12 and maybe it is for the reliability issues that seem to be stated often? If the Ferrari V12 is more reliable nobody would really know it is not a Jag V12 as you could easily badge it with Jaguar and it would show the 12 individual stacks? if your budget allows? If not regardless of the power plant it sounds like a great car!

 

Hi Scott and Fran from Fox; and greetings from down under. As someone who has played hard with many V12 Jag engines - the wildest of them in the prop-rider "Jaggered" with our Twin Turbo 6L HE with custom pistons and twin water injected megaphone exhausts (just shy of 650 shp @ 7800rpm)- I applaud your enthusiasm but caution that you will find it hard to reproduce the XJ13 image from any production Jaguar engine.

"A Jaguar V12 does not an XJ13 make" so grab Fran's offer to talk quad cam. Unlike your earlier post, you will find any such to be as rare as rocking horse doo doo and I just can't see the twin cam V12, while streets more appropriate than a crate V8, carrying off the illusion. Strangely, I even think you would convey a more realistic build with a modern Jaguar STR V8 quad cam - with or without supercharger.

Again, like Fran, I see your choice of transaxle an equally critical choice. Depending on how many ponies you have feeding into it, the big rib ZF transaxle can be recommended. Try the circuit sports car racing fraternity for help to locate a source - they have loads of experience with them.

This is only my personal 2c and I am aware of many around this forum who also have held aspirations towards a Quad Cam Jag V12. Lock up your checkbook, and go talk to Fran. I like the sounds, the looks, and the smells of authenticity that he conveys ... and please, between you, keep posting your progress for all of us to enjoy.

Best wishes,

Ken

 

Thanks Primaz and Ken for your posts. The input is appreciated.

At this point, I have finally dismissed all notions of a crate V-8 or other non-Jag power plant and have gone forward with a decision to have Fran source an XJS V-12 and rebuild it, then develop a bespoke EFI system for the top end with some of his unique velocity stacks. I am leaving to Fran's judgment and expertise all technical questions regarding cams, pistons, bore etc. as such matters are his bread and butter and way over my head anyway. Having seen photos of many examples of his work, it is clear I am in good hands there.

As a general matter, I don't plan to enslave myself to the gods of authenticity with this build and am doing some things (such as carpeting!) that will strike the purist as anathema. So be it. I will be glad if the end product is a sincere homage to the spirit of the "13" even if exact details vary.

Still unclear what we will mate to the unit by way of transaxle. I used to have a crackin' ZF 5-speed, but as it happens it was attached to the Ford 351c that was mounted in my '71 Pantera and I felt it was only gentlemanly to leave it in place when I sold the car last year.

So I'm moving ahead and making progress. No pix at this stage unfortunately--hoping to get some soon from Race Car Replicas so I can share. I did succeed in getting my hands on a California "Certificate of Sequence", which those in the CA replica world will recognize as a passage to lifetime freedom from mandatory smog inspections. (They give out 500 per year and I succeeded in obtaining certificate no. 15 at about 11:00 a.m. on January 2. The early bird gets the worm, etc.)

Hope to have more news and views soon. Thx for your interest and input all. Meanwhile, regards from the SF Bay Area.

Scott

 

Way to go Scott ...

I agree that trying to micro-manage all the tech bits when you have someone like Fran on board, is a waste of energy - and liable to relegate your vision to just a dream.

Also, I agree with your focus on that sweet ZF 5speed. You really are a gentleman ... I see no problem with a Pantera "free-wheeler" if the alternative is a replica XJ-13.

Great to see you are already on the ball re pics along the way as the build proceeds ... Fran also? Even from afar, many of us addicts still want to drool!

Best wishes with a great project,

Ken

 

I've been away from this thread since building up a separate one to discuss my XJ13 replica project. That other thread has numerous postings by now that some may have missed if you're only looking here, so feel free to go over and see where we are with the build etc.

Fran Olsen of Fox Engineering built a fabulous injected V-12 and Race Car Replicas is in the final stages of completing the build. Details, pix and vids here:

https://www.jaguarforums.com/forum/o...13-jag-127341/

Regards,

Scott