So, I was very annoyed that there was very little information about jag performance on this site, and even more miffed by the fact that you had to go digging all over the forum to find it.

For my first foray into the jag performance section I'm going to put together some information from some of the threads I spent lord knows how long sifting through to get some cohesive information on Jag performance. (of course this comes form people more knowledgeable than I, on this forum)

Let the fun begin!


For starters your basic Jag 4.0, from 1997-1998 can be found in the xj8 xjr xk8 xkr.

This is an all aluminum block with a Nikasil coating as opposed to steel cylinder liners. Read here to learn about Nikasil http://en.wikipedia.org/wiki/Nikasil

Nikasil is supposed to be "the best" as told by my engine builder. It's used by Porsche and superbikes. It has better wear characteristics than do steel liners. Supposedly with less friction (I am no expert however) This is fantastic as long as you don't use high sulpher fuel, as sulpher eats the Nikasil leaving you with a very heavy expensive paperweight.

What does this mean for performance engine building?

I'm glad you asked! It comes into play when delaing with rebuilding the engine or applying the time honored hot rodding technique of "boring the engine out". Whereby you bore the cylinder bores out creating more displacement.

Bore out the 4.0

You can't just "bore out" this engine. If ou do you have to either recoat the cylinders with Nikasil, or install steel liners. Both of these options are very, very expensive. If you can even find someone to recoat the block (there are no facilities for this in Hawaii for those that care) it's a $2,000 job. Steel liners are a pain and it takes a GOOD machine shop to do it, and do it right, will run you slightly less than that around $1,800.

4.0 camshafts (cams)

The next thing any good hot rodder will tell you to do is swap the cams. Variable valve timing on the intake camshaft makes this a giant pain (the 97-98's can shift it up to 30 degrees). Not to mention that there is no aftermarket support for this engine. So you cannot just go and pickup a replacement camshaft drop it in and reap the horsepower gain that it would offer. HOWEVER, what you can do is find a machine shop to "regrind" the one you have. they can weld material onto the camshaft lobes and "regrind" them to a more performance oriented profile. IE adding duration and lift.

Headwork
Another time honored technique is to unshroud the valves and port and polish the heads. This you can do. It's costly ands requires head removal but is a sure fire method for increasing power across the board. Depending how radical you get this can cost anwhere from $1000 if you pull the heads yourself and bring them to the machine shop to several thosand or more if you do less work and have an expensive machine shop. (i personally recommend DR racind in AZ) they have done several sets of 3000gt heads and a set of viper heads for me and their work is second to none. (shameless plug I know)

BOOST!!!

SOOOO you want to boost your jag huh?
Go buy an XKR. No really, i'm not kidding. Sell your car and buy aan XKR. It will be cheaper in th longrun.

Here's why. Boost requires


Bigger injectors $
new fuel pump $
supercharger or turbo $$$
all related hardware $$$$$$
all related installation cost (or time if you're a DIY kind of person) How much is your time worth? $$$$$$$$$$$$$$$$$$
Aftermarket ECU $$$$$$$$$$$$$$$
A lot of serious tuning by a REPUTIBLE shop. $$$$$$$$$

Engine management software for the Jag is non-existent. There is no easy flash for the ECU like a Subaru. You need custom engine management. A full ECU from AEM will run you $2,000. That's just for the part. Have a good time installing this thing; have you seen your wiring harness lately? Now you need to upgrade the injectors, 8 of them. You also need the supercharger or turbo and all related tubing and hardware (many thousands of dollars) Even if you find the xkr supercharger on fleaBay for 800 bucks you don't know its condition or if you need to put several hundred more dollars into a rebuild. You will also need a bigger fuel pump (a Walbro 255 should do the trick to the tune of 99 bucks.) The installation is a huge PITA to boot.

Furthermore, you need new pistons, stronger ones preferably, but at a minimum ones with lower compression, much lower. Pistons =expensive, installation = expensive.


And no, you can't just drop the supercharged engine into the N/A (naturally aspirated) car. Wrong, ecu, fuel pump ect. There's a lot of extra parts and wiring going into this nightmare swap.

 

Ahhhh a post from viscous at last in this section

Nice one

 

Err Squirrel, I think you may have just proven the point of why there was no perfomance engine section.

It just aint done.

 

perhaps if you give people the outlet, instead of treating it like a redheaded stepchild it will happen. Furthermore, what little there is, is still asked about weekly. Now they have a place to congregate or at the very least read this and get an idea...

 

You might want to update the title to denote this is for the 4.0L AJ8 and not something like the 4.0L AJ16.

 

I guess there is a god... I've been dreaming for the creation of a performance specific section for sometime now. I've got big plans for my XJR

 

Is there anyone who can tune these cars?

 

When I modify my XJR I will go to Unichip and remap my own car. I don't trust the after market and the companys in the UK are by far the worst! ( When I used to work for Jag I used to have them phoning me to hound me for knowledge offering to buy me dinner as payment- such is the 'value' in the UK for engineering knowledge! Now I see them charging an arm and a leg for quite unremarkable work. Especially unremarkable since I'm getting into modifying old Dodges and the breadth of services on offer there!

At one time I toyed with the idea of setting up a company to handle modifications on Jaguar cars, and certainly with the exceptionally poor salaries of UK engineers at Jag, it would have been a step in the right direction (didnt you know that Jaguars were engineered on super lowEnglish slave wages compared to what American engineers get paid? ). Now I have landed myself in a killer senior job at an American OEM and have been seduced by the security- modifying Jags will be relegated to just a hobby. If I do start under taking mods on my engine I will share it with the forum and perhaps do group buys (as long as my time is respected).

 

Count me in on the cams!

I have been in contact with Darton about sleeves as the boring out has been on the list. However what hold me back was the current thin wall at some places is just 3.5mm.

Keeping in mind that the engine would of course Twin-Screw charged (so pretty powerful), I didn't dare to go smaller than 2mm for the sleeves, and 3mm of aluminum wall. That unfortunately would only yield to 88mm instead of the stock 86mm bore, so not worth the effort. Of course it would have gone together with a longer stroke crank, and then 4.5 would be easy to achieve, but still too expensive for me.

How thin do you think the aluminum wall could be and also how the darton sleeve, yet be still strong enough (for the R cars)?

 

The stock engine block isnt siamesed so as you correctly say, it becomes dangerous to go to small. Darton are able to put in an strenthened insert and get very close on the bore to bore bridge distance. You will now have a siamesed engine most likely which isnt ideal but BMW have been selling siamesed engines for years. You can use a Cometic gasket to seal- Cometic already have a 93mm bore gasket. I wouldnt bore out the aluminium wall without some kind of liner- the aluminium is too soft a material to work with our pistons. The only thing that worrys me a little about boring out excessively is that now the engines torsional vibrations of the crankshaft have been altered. I would have to confer with a colleague as to how significant this is.

 

Agree with you about boring out the aluminum, I also wouldn't want to do that unless you use a strong liner (like the darton ductile ones).


I have found a very young 4.2 engine block (from a Range Rover, 2007 iirc) that seems to have a thicker wall compared to the older AJ33/34. With that block I am more confident to bore it out and together with the ductile sleeves to get a (hopefully strong enough) 92mm bore. Combined with a 92 stroke you would get about 4.9 ltr, which would make it more worth the job imho (if I had the funds…).


Another option I was contemplating was to go for wet liners, but have not enough knowledge/experience to judge if that could be a better option. What keeps me back there is the relatively small area that can be wet. Difficulty you hear is that it is much harder to get perfect fitting of the sleeves, so more costly.

Would be interesting to know about the torsional vibrations and what sort of risks you introduce.

 

Here comes the diffident voice of a 'newby'. Or, at least, new to this forum. My car is an '02 Lincoln LS. Cars built on this platform use an engine of 3.9 litres displacement---a variant AJ that came from the Lima, Ohio engine plant.

I started Land Speed Racing after a short stint of observing, and, to stay focused on engines for this exposition, after setting the National ECTA record in my class---E/F CC---I am now determined to move over to the 'blown' class and, in furtherance of that goal, I'm redoing an AJ 27 engine of '99 vintage. This particular specimen came from the factory with ferrous cylinder liners.

I first did a study to discover the mechanically weak points to the engine design, and concluded that the cast pistons, and the powdered-metal rods had to go. Since land speed racing requires intensive engine effort, but only for relatively short periods of time, the design improvement parameters are somewhat different than if one were to be building for endurance road-racing. I am very lucky in that I have contact with, and input from, RSR, the Jag 'works' operation here in the US for International Road Racing. My most emphatic thanks to Mr. Tony Gentilozzi for his help and input.

To do a proper job of exploring this subject will take enough effort that I'll be coming back to it at regular intervals. I'll also be happy to entertain any questions you may have, so let's have a good discussion. I won't guarantee to have all the answers at my fingertips, but I'm likely to have some sort of idea as to where to go to get input.

KS

 

it seems as tho some things should be addressed 1st?

does the basic cylinder block have the INTEGRITY to withstand serious internal stresses, both thermal and mechanical.

was it designed as a light weight passenger car unit, or did Jaguar think of it as a hi-performance race engine while they were designing it

can it produce 1000-1200HP with some real confidence, forced induction(turbo or supercharged). aluminum blocks have a tendency to twist when temps go hi and hi loads, mains go out of alignment, and bearings dont seem to happy.

been to the Texas mile for past couple yrs, seen a lot engines spread all over the track.
and im aware that 1 standing mile is just a 1 mile DRAG race, its about a lot of torque and tire hookup quickly.

and the flying miles at Bonneville are completly different, plenty of time to get up to speed. been there too.

anyway without goin off topic, is the basic block strong enough?

i myself have done Darton sleeve machine work, and the strongest was the custom wet sleeve liners, completly machine away all the aluminum bores, and have free standing liners, weak points being head studs in a position to keep the head from to much lifting.

i did some Ford 4.6s and 5.4 V8s.

cometic seems to make gaskets for anything.

some 4 cyl. aluminum blocks we had to manufacture head studs that clamped the main bearing girdle up thru the cylinder head, all the way thru the block, like a big sandwich.

it held the crankshaft to the cyl. head , to keep them from parting company.
1000hp 2L 4 banger, all it takes is money.

 

I have NO wish to hijack a thread, so it's probably better to start something new instead of walking on someone's toes. I'll be somewhere around with both answers and questions.

KS