Hello to All, I have a 1984 VDP that for the last couple of months I have been mapping out with chalk lines on the garage floor, A tape measurer and graph paper to find that a 1995 AJ16SC motor should just about fit with a shortened front drive shaft. I only have one quandary and that would be how could I drive the speedometer? There is a output shaft speed sensor from the transmission, But that wouldn't provide the type of signal that the original speedometer would need. I have the original instrument pack to the vehicle but haven't a clue how I could fit it into the original speedometer binnacle.
Any suggestions?

 

Hi Larry,

I love your idea! Having the power of an AJ16SC in perhaps Jaguar's most beautiful saloon ever would be pretty amazing.

However, the complexities of the later systems pose a lot of challenges. In the X300, the ECM, TCM and ABS/TC Control Module are all interconnected via direct analog connections as well as digital Serial Communications.

The vehicle speed signal comes from one of the wheel speed sensors (front right, if I recall correctly) via the ABS/Traction Control Control Module. But the vehicle speed signal doesn't just drive the speedometer, it is also critical to the Engine Management System and TCM for determining ignition timing, gear selection, shift points, engine torque reduction, traction control, etc.

Since the ABS/TC CM is integral with the brake modulator unit, I don't know how you could get around using the X300 brake system.

Which raises another possibility: If you could use not only the X300 engine but also its front and rear independent suspensions, you'd get the ABS/TC system too.

You'd still have to figure out how to drive your dash instruments, which might not be insurmountable. It appears that the transducer for your existing speedometer converts rotary motion in the transmission to an electrical signal that drives the speedo. You might just need to develop a "translation" system to translate the signals from the X300 ABS/TC CM and ECM so your speedo, tach and other gauges would respond correctly. That might take a lot of work, assuming it's even possible.

I hope other members will have some input. I'd love to see you accomplish this!

Cheers,

Don

 

Hi Larry'
I will be attempting to fit a 4Litre AJ16 SC engine into a 1976 XJS cabrolet which was built by LYNX in the UK as a V12 with 4 speed manual but purchased minus engine and gear box. I have fitted earlier AJ6 3.6 engines into series 2 and 3s in the past with no problems as i used the early type Getrag manual G/Box that still has the speedo drivein tail of the box.As Don B explains very difficult with later AJ16 engines. I think the only way around this is to run with after market ECU for the fuel side of it and may be a GPS system for speedo; I think they use that system in Rally and race cars. Interesting project at least with the Series 3 you have the right fuel tanks and larger fuel pipes with change over valve already in place' You may need to change the fuel pump as the AJ16 S/C runs 2 pumps in the tank.
Cheers Ray.

 

Thank you for two great idea's. I had all ready been considering a single right front wheel speed sensor utilizing a upright, sensor and hub from a late model XJS but to use a complete four wheel system to have a speedometer signal when I really don't need ABS/DSC in the first place feels like a whole lot of extra work. One HZ signal converted to a pulse signal generated to drive a speedo head would be all that I need plus what the engine would need as road speed. However a GPS signal to tell the speedo head and the engine ECM how fast we are moving would be real cool but probably over my head of getting done. Who would I contact about this Rally/ GPS speedo idea?
Larry
As far as the fuel pumps, I was going to use the original Series III fuel pump as a supply pump into a swirl tank. Two high pressure pumps inside the swirl tank would supply the engine but the return system would remain the same.

 

As far as using the GPS for speed all you need is a GPS unit, even a hand held. I use one to calibrate my speedo in an older car. As to how you drive the instrument? Well...i'm not even sure the rally guys do that. That would be cool though.

Well... I guess I wasn't much help. But it sure sounds like fun.

 

Larry,
It is possible to buy programmable speedometers from companies like STACK that are claimed to be compatible with most OE vehicle speed sensors. I would expect that the output shaft speed sensor on the GM Hydramaitc 4L80E transmission which I assume that you have already fitted to your AJ16SC engine could probably be used to drive one of these programmable speedometers. Good luck with your project. These engines have now been used to power a large variety of different project cars.

 

Hi Larry.
A manufacturer in the USA called Speedhut does GPS speedometers.
www.speedhut.com/gauges/GPS-speedometers All the best for new year
Cheers Ray.

 

Look for an interface box made by Dakota Digital. The output shaft of the 4L80E puts out 128,000 pulses per mile, and the Jaguar speedometer wants to see 8,000 ( I think, it might be 4000; I'm going by memory). The box is a translator that can take the signal from the transmission and feed it to the speedometer and cruise of the Series III.
Universal Speedometer Signal Interface

You will need the electrical manual for the XJR to make this conversion. You will just need the fuel and transmission ECU's from the XJR, but there are other systems like the ABS that you have to fake the inputs with either battery voltage or ground to tell the ECU that the traction control is "off", when in reality it's not there. The electrical manual will tell you what the signal is for the active and inactive state. The manuals are on the CD's produced by Jaguar Heritage.

I have been contemplating doing a repowering project with the XJR engine and I think that fitting the engine mechanically is the easy part, making sure the electronics is correct is a greater challenge. I have no problems reading the electrical manuals, and have spent many hours pouring over them. It's a doable conversion, just will have to be done with care and methodically. I've converted a 1966 S Type to EFI from carbs using Megasquirt and developing the fuel and ignition maps for the EFI is not a simple task. After doing it once, I would never try and recreate the curves for the XJR in an aftermarket controller, it's easier to do the wiring and keep the Jaguar ECU's.

 

Plus one on the Dakota Digital box. I used one in my TPI powered '86 XJ6 with a TH700r and it worked very well with the original Jag speedo.

I'm on the verge of undertaking this exact same project. In my garage is a 1997 XJR with 80k one owner miles and a 1972 XJ6. Just arrived via air freight from England is a Getrag 5 speed and bellhousing from an XJ40, 70's clutch pedal box and adapters for the AJ6 and AJ16 engine block (and a couple of driveshafts). AJ16SC and 5 speed are destined for the '72.

I've been weighing the Megasquirt vs. OEM ECU problem. I currently have two options.

a) Megasquirt. A successful build is here. 1970 Jaguar XJ6 | Retro Rides

b) OEM ECU but reprogrammed. https://www.jaguarforums.com/forum/x...emapped-66907/

Each solution has it's drawbacks.

- Megasquirt. Adapting the existing harness to work with the Megasquirt, coming up with a good map to provide reliable starting and power.

- OEM ECU. Convincing it that there is still a GM electronically controlled transmission and ABS braking system still communicating something clever to it. OR. There's only one person on the planet who can reflash the Jag ECU and his price to do so is almost identical to the price of a Megasquirt with the electronics necessary to run the AJ16 systems (Coil on spark and sequential fuel delivery) as they are.

I'm openly soliciting opinions and VERY interested in hearing from anyone else who's attempted AJ16 engine swaps.

-Bill

 

The original post was how to drive the Series three speedometer from new electronics found in a 1995 XJR. The outcome has myself leaning to the Dakota
box in order to keep the interior appearances looking original but I am intrigued
by the GPS speedo idea which I will contact both GPS speedo companies to find out if they can make it work inside of the original housing/ Bezel and Background. The next problem raised that I never considered was the vehicle speed input from the ABS/ Instrument pack from which the ECM needs to form it's mapping strategy. Looking for the simplest answer will probably be to go back to the Dakota box and see if it can provide the same answer that it did
for the Speedo. Possibly either splitting the signal or simply a second box.
The cylinder head and front cover is off the AJ16SC motor for chains, reseal and freshening of the head gasket. Another weekend or two, Reinstall the trans, Pull the 4.2 and install AJ16SC. Know any one who needs a 4.2 motor and trans in Florida?
Thank you again. Larry Louton

 

I have done one Megasquirt (MS) install, and a close friend of mine has done 3 (2x Chrysler 440, and a Ford 390) and we have worked together on them.

The options you presented of MS or reflashing the OEM ECU are quite different, and the best answer for you will depend on you.

The OEM route has the advantage of the fuel and ignition maps being developed by Jaguar and are a proven thing. Once you have built/modified a wiring harness with the appropriate inputs to the ECU then it's a running car with the Jag OEM starting and running qualities. Downside is cost.

The Megasquirt route will be no cheaper you say, so a wash there. It will be time intensive, as MS's greatest advantage and biggest liability simultaneously is in it's versatility and flexability. There is no default setting for anything, you will have to learn and understand literally hundreds of parameters and understand how they interact. Like it or not, you will be doing a lot of reading and thinking of how to implement MS on your engine.

I have found the MS route to be very iterative, and to do it right you will be spending a lot of time looking at datalogs and intrepreting what they mean and what setting will be needed to be tweaked to get the results you want. Ideally this should be done on a chassis dyno, but it would still take many hours (and $$) to get the fuel and ignition maps correct across the entire load range.

One thing that I think I great about the OEM system is the knock sensitive ignition, and I don't think there is a practical way to implement it in MS, as there isn't a good way to measure knock in MS to know when it's present or not.

A pro of MS is it is a great learning and educational experience, you will have a very good understanding of the combustion process when you are done, but to get a system approaching OEM quality will probably be a multi year process of driving, dataloging, tweaking and repeat. Yes, you could probably get the car running in a weekend, but getting that last 10-15% dialed in will take a lot of time.

Go MS for the experience and learning, go OEM for the most painless way to get the engine running with the best performance, smoothness and best starting.

If I had an engine for which there is a good OEM ECU available I would always use it. Use MS for engines with carbs, or to replace poor first generation EFI ECU's.

 

Thanks for this excellent advice. I've done a couple of swaps and always imagine that it will be far easier than it ever is. The first time you think it will take you a weekend and the next time you wonder if you'll finish it within a year. I like learning new things and the idea of having complete control over the system with MS is so enticing but I think I'd rather drive than design fuel maps.

-b

 

To all those interested, I am going to the OEM route because I collected with the engine/trans, both wiring harness's, Both ECM's, Instrument pack, Catalytic converter, Cooling fan's, Both radiator's with all hoses, Shifter with cable and linear switch. After disconnecting the 4.2 engine, I wouldn't think that it would take more then a 1/2 day to get it out and hopefully stick the
AJ16SC right back in. Hooking it up is going take as long as it takes.
Happy new year.

Larry Louton

 

I am interested in how it works for you as it is your best option having all the other bits to mate with it keep us posted on your progress. I will be starting my conversion in the near future AJ16 S/C into 1976 XJS Cabrolet but going with a 290Getrag manual; I fitted one of those gear boxes to a 1997 XJR a few year ago and had to have my ECU remapped. So for that reason i will probably go with an after market ECU im thinking of LINK which i think they use in the V8 super car series in Australia and NZ. But first i have to put a new floor pan in.
Cheers Ray.

 

Hello to all, Haven't contacted Dakota digital yet but that seems like the easy part now unless maybe I can tap out of the digital box and use that for the vehicle speed input to the engine control module. My XJ6 electrical manual doesn't offer any spec on the speedo except for part substitution. I will have to remove the speedo this weekend to see what kind of signal it needs.
Found specification of outputs for the ABS/Trans/ECM system. The wheel speed sensors each produce about 100 Hz at 10 mph and about 200Hz at 20 mph. The Transmission output speed sensor produces 300 Hz at ten mph and 600 Hz at twenty mph. The ABS module sends the same HZ signal to the Speedometer for it's vehicle speed input and then cuts down the vehicle speed signal Hz to 20 Hz at ten mph and 40 Hz at 20 mph for the engine mapping.
That is what I mean by I have to find a way of cutting down( diet ) the Hz signal to the engine signal from the trans output sensor.

That is where I am at.

Larry Louton

 

That's exactly what the Dakota Digital box will do.

 

Finally got my courage and went looking for this interface by Dakota Digital
and there it was. My last worry is gone and now I can finish the engine this weekend then remove the 4.2 and start installing the 4.0.

Thank you.

Larry Louton

 

Hi All,

I am in the process of doing the same thing - putting a Supercharged AJ16 engine into another car. In my case a Series 2 XJ6. The ongoing process can be seen at rdowden.com (no selling so hopefully OK to post url?). I had a complete XJR to start with so I am aiming to use the ECUs as needed with the minimum amount of wiring. I will be using the engine/trans/body and security control boxes. As for the speedo, yes the original speed signal did come from the ABS unit which I am not using. The gearbox does have an output which can be divided down to get something close to the required ratio. The output will then go to the original XJR circuit board that drives the dash and fit the small electronic motor that drives the XJR speedo inside the original speedo case. I did a test fit on a spare one and it works out quite well. At this point you can then just adjust the output voltage to fine tune the position against the original speedo faceplate. Still a long way to go but having fun on the way :-)

Worst case, I drop all the original XJR electronics and go to a standalone ECU like the MS one.

 

Hello, first, pleased to meet you and your project. My 95 XJR did not have the security feature in it. Hence, I don't have to deal with that. Dakota digital has a very simple adjustable Hz splitter box if your interested in that. Are you putting the XJR speedo motor inside of the Series 2 speedo binnacle? I am not a seller, More like a buyer/ hoarder. Looking for front turn signal assembly's
for a Series 2 euro bumpers to go with a set of euro bumper blades I found?
I am going to try sending you a e-mail, Look for something with the word fish in it and send it back to me.

Good luck and go with grace.

Larry Louton

 

What you might wish to do is get an ECU for a North American spec car, as it doesn't have the security inhibit like the European cars do, then you can do away with the security module. Then you can use the original wiring for the starter, and just connect the heavy gauge starter wire to the XJR starter, like the S2. I think you can eliminate the body processor then as well.

If you use series 3 speedometer and tach, you can use the Dakota Digital box to drive the speedometer off the output shaft speed sensor of the transmission, so that will keep the Series 2 look. You could probably put the Series 2 faces on the electronic Series 3 instruments to make it look completely original.

Just be aware that the 96 and 97 NA spec XJR's have EGR, the 95 doesn't so the ECU's are different between those years. All the NA spec cars will have 4 O2 sensors though, and I don't think the European cars have 4, only 2 ( not sure about that).

Regarding fuel, what I have seen done for the conversion on a DS420 was to take the XJR tank and mount it in the front of the boot and remove the twin tanks. All the evaporative emission lines of the XJR were retained, and the fuel pump in tank just wired up. Filler can be adapted like a late XJS, on one side only. For that matter, a late V12 XJS tank might work, as the 6.0 also had twin fuel pumps. Worth some investigation.

If you do this, then all you need is the ECU and transmission ECU, so that makes it easier to find space inside the car for wiring.