3.9 injection V8 help please.

Hensen1954

Hensen1954

Active Member
Just bought the above, Range Rover engine, I guess, anyway need help with ecu info. Has it got to be exactly the original fitment, or can you use other models, maybe off a 4.6 or whatever. If it affects anything, looking to throw on a rear mounted turbo as well.

All help appreciated. Thanks.
 
Hi Hensen,

As far as I am aware, the injection systems for the 4.6 were designed for that engine, not to be retro fitted onto a smaller capacity engine.

What is wrong with the injection system that came with the 3.9?

Ron.
 
Hi Hensen

All this stuff I've learned when googling for my own plans, so take with a pinch of internet salt..

Looks to me like that's a 14CUX controlled 3.9. The 14CUX has LOADS of info on it on the internets about how to set it up and get it running, it looks pretty easy to be honest. That coupled with an electronic distributor (which it might have one of already, but with a 4x4 advance curve) would set you up OK. It can run closed or open loop (i.e. with or without Lambdas), and is actually apparently better for power and economy without them (according to the net..)

The later GEMS (4.0) and THOR (4.6) systems won't fit on without a lot of effort. The THOR in particular is all coded within the car, so you'd likely need gearbox ECUs and a huge pile of other stuff potentially to get it working, I think. Other way round is OK, you can run the GEMS and the THOR engines on the 14CUX with a little messing.

Even earlier and simpler is the lucas 'flapper' system, which is not that clever and more like carbs (has an extra injector for cold start for example), but it is brutally simple and seems to be very accepting of mods, though I'm not sure on the forced induction side.

If you're doing it 'properly' (read-expensive, in my book at least) then the advice seems to be Megasquirt, which is fully mappable ignition and fuel and can be easily modified to cope with a big single turbo. It's open source, so anything maps wise that can be done has likely been done and is available.

In answer to your original question, if I had that engine I'd be putting a 14CUX on it and then it's going. The year is unimportant, as the map is selected by a resistor in the loom (they had different maps for different cars). The better ones have a removable chip inside that can be upgraded, but it's poor value for money in my opinion compared to Megasquirt.
 








Just started messing around to see if the Mustang T-45 will have any chance of mating up tot the 3.9, think it might need some severe modification, but both have a 10.5 inch clutch plate and similar compatible dimensions.
 
I don't know so much. If that gap is uniform all around, then it's just about thick enough for an adapter plate to bolt it straight on.
The spigot bearing would be a bit of work but the biggest job will be the flywheel/clutch. If the vehicle is/was already manual then
you are over the hump already as it's simply a matter of adapting the connections to the slave cylinder for the Mussy. If it's a full
auto to manual conversion, then it gets to be really fun.
On the P6 it's a matter of the manual pedal box and master cylinder to fit and plumb in. Other types will be a variation on that.

Considering your 3 engined project, this should be a walk in the park for you, though. By the way, how is that going? :mrgreen:
 
If its the same as the t5 box, you could look at a tvr setup to get the right clutch and bellhousing...
 
Engine number 36DXXXXXA is a factory high compression 3.9 litre built from 1988 onwards for Range Rover and Discovery vehicles.

Ron.
 
Hensen1954 said:
Just bought the above, Range Rover engine, I guess, anyway need help with ecu info. Has it got to be exactly the original fitment, or can you use other models, maybe off a 4.6 or whatever. If it affects anything, looking to throw on a rear mounted turbo as well.

All help appreciated. Thanks.
Click to expand...

Hi Hensen,
I've changed my SD1 Efi system over to 14CUX(hotwire)from 4CU(airflap), along with the 3.9-litre motor. It's a much improved Efi system over the 4CU as it uses less components. I've also been informed by a local Land Rover independant that the 14CUX ECU has a 100% reliability record in normal use. The earlier 4CU ECU has some issues.

The 3.9, well, bigger bore, more torque at lower revs, more power etc. superb motor! I'm guessing you may want to strip yours down to check the bearings, bores, etc. I bought my 3.9 from a pallet board untested, which wasn't a very good idea. On first start up it sounded like a tractor :cry: Sure enough, one of the big ends was shot, along with some odd valve lifter noises.

To just get it going I fitted some new main and big end bearing shells along with new valve lifters and rods. Not normally a good idea without a crank regrind, but after 4K it's still going strong. Testimony to an unstressed engine I suppose.

Range Rover were testing a Janspeed Turbo version back in the eighties which was a 3.9-litre 14CUX with impressive results.

The CUX Efi is very easy to install. It should actually run with just 3-wires connected, leaving off the 'road speed transducer', and 'in neutral' wire. I've since connected the 'in neutral' feed via a resistor which keeps the idle speed constant. The transducer needs to be specific to the system.
 
Thanks for all the help everyone. Yes they were / are both manual set ups as original. The spigot etc is correct as is - just pure good luck. Am looking at the possibility of a hydraulic clutch bearing set up. I think I will need to do some serious mods to the bell housing, but first I have to check if the Mustang box will fit easily between the M30 Chassis rails, that go alongside the gearbox. Maybe the SD1 box will be a better fit. I already have an M30 with a Ford 302 and FMX auto behind it. I had to modify the chassis rails to get that auto box in and clear.

This 3.9 has these heads fitted and I am told has had a rebuild with work. Will check it out though.






The 302 M30 can be heard here..

http://www.youtube.com/watch?v=h4EuCVyfiB4

The Rover is going into this black M30.


 
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