1994 NAS Discovery Diesel Conversion

I have been contemplating swapping a diesel engine into a land rover discovery for a couple of years. The overall goal of my project is to build a rock solid multi-use SUV that I can drive for a long time. The truck will need to have good road manners balanced with good capabilities off road. I really like the Disco, it's a great truck with a lot of off road prowess without the high cost of a Defender or a Jeep. The only downside to the rover is the horrible range that you get with the rover V8 offered in North America. 19 gallons of fuel gets you about 220 miles. Converting my truck to diesel power would increase the mileage from 12mpg to somewhere around 22-24mpg, effectively doubling the cruising range of the truck. The other downside to the V8 is the factory electronic components which are notoriously unreliable.

I know Land Rover sells a variant of the Discovery in other markets that are factory equipped with the 200 and 300 TDI. These are great engines and I may still end up going this direction but I want to explore all the various possibilities. I also currently live in California, so using a USDM available engine is something I need to weigh heavily. A 300 TDI is also fairly heavy compared to a VW TDI, so taking a hundred pounds out of the nose would offset some of the other additional equipment (winch, etc).

300TDI Specs:
Layout: 4-cylinder, in-line
Block/head: Cast iron/aluminium alloy
Valves: OHV, belt-driven camshaft, push-rod operated
Capacity: 2,495 cc (152.3 cu in)
Bore × stroke: 90.47 × 97 mm (3.562 × 3.8 in)
Compression ratio: 19:1
Fuel injection: Bosch VE rotary pump and Bosch two-stage injectors (with Bosch EDC system on versions with automatic transmission)
Induction: Allied Signal T25 turbocharger
Power: 111 hp (83 kW) @ 4,250 rpm (versions with manual transmission)
122 hp (91 kW) @ 4,250 rpm (versions with automatic transmission)
Torque: 195 lbf·ft (264 N·m) @ 1,800 rpm (versions with manual transmission)
210 lbf·ft (280 N·m) @ 1,800 rpm (versions with automatic transmission)

So here’s the question.
Can a VW TDI be built to work in my truck? What about a mechanical injection pump? Can I get 250 lbft of torque with the right modifications?





I will also be using this thread to organize my links and references. I appreciate your feedback, but please be constructive. negative comments don't help anyone.

w00ht and I are very good friends and we have batted various TDI combos around for years for this and his VWs. I'm torn between recommending:
§ a Rover diesel which would swap in and have difficult parts availability
§ swapping in a VW TDI and having a complicated swap to say the least

He has been kicking around an M-TDI ALH/AHU while I try to convince him that there are not many proven M-TDIs with 150+ whp and that having an electronic TDI is the way to go.

I think he should look closely at what people have done for Toyota TDI swaps and follow one of these routes if he is certain a land rover diesel isn’t for him. Remember he is located in California so there could be some minor issues when registering as a diesel for the first time.

I'm not opposed to an electronicaly controlled TDI, I know they make good reliable power and as long as I can simplify/weatherize the harness as much as possible I'd be fine with that as long as I don't have to swap in a VW cluster or Key. An imobilizer defeat so the ECU can run stand alone would be required.

before I found my tacoma I was about to pull the trigger on a blown engine rover for an ALH swap...I think it would be an unbeatable vehicle....but I would definitely go electronic and manual...I'm sure a toyota trans could be made to work as all the toys up until the the tacoma had a right side drop just like your rover....it's easy to to say "go for it" but after putting 12k miles on my tacoma swap and loving every mile I'm convinced the TDI is the ultimate swap for compact/midsize 4x4's

Jimbote's swap is one of many worth taking the time to review and it is a standout.

jimbote said:

before I found my tacoma I was about to pull the trigger on a blown engine rover for an ALH swap...I think it would be an unbeatable vehicle....but I would definitely go electronic and manual...I'm sure a toyota trans could be made to work as all the toys up until the the tacoma had a right side drop just like your rover....it's easy to to say "go for it" but after putting 12k miles on my tacoma swap and loving every mile I'm convinced the TDI is the ultimate swap for compact/midsize 4x4's

Click to expand...

Thanks for the input Jim, I was planing on a 5 speed swap regardless but a yota trans may be the answer. I had an 88 3.0 4x4 on 35's that I used to beat the crap out of as a young kid in the Navy. I wonder if I can make the emergency brake setup work with it. The rover has a drum setup after the rear case output.

Several people have successfully done Mercedes diesel swaps into 5 speed discos. Those would be emissions legal as long as the engine is new enough.

k_harley said:

Several people have successfully done Mercedes diesel swaps into 5 speed discos. Those would be emissions legal as long as the engine is new enough.

Click to expand...

I've looked into the OM617 but I don't think it came in new enough cars, I think they stopped using them in the mid 80's. I need something 1994 or newer to be completely inside the CA rules. While they define bulletproof, they make about the same power as a tuned VW TDI but weigh more.

I have driven a diplomat owned Disco with a 300 tdi - It ain't quick, let me tell you. Disco's are a bit like a brick on the highway....

If you went with a tdi, be prepare to put some money into raising to power level by quite a lot - i would say that 160hp would be 'ok'

Cool looking rig! Can't believe that it sucks so much fuel, no wonder you're looking for TDI alternatives. They do seem quite a bit heavier then the Toyota's though. What about importing a 2.5TDI, it might be cheaper then building a 1.9. I seem to recall they were around 150hp stock and nearly 180hp with a fairly modest chip, don't quote me on that though.


This may answer your e-brake question, they are fairly common with the Toyota of road crowd:

http://www.sky-manufacturing.com/new/detaproduct.php?id=142

I bet you might be able to hook it up to your stock cable with minimal mods.


Looking forward to the build,

Luke

^^what Luke said....an easy (by comparison) obstacle for sure ....I'm so jealous of you solid axle guys ....not much to worry about in the way of pan clearance..... really looking forward to your build!

I did a couple hours of research interested in doing this conversion a while ago; more so with the next generation disco and importing a BMW diesel(its a lot more complicated).

Since you have the previous generation go with an ALH gtb2260vk(gearing is gonna keep you in that sweet spot) retrofit the vw cluster and whatever else is needed to be electronic. The toyota route sound proven...not sure if adapting to your current trans will have the correct gearing.

Nice truck BTW!

Thanks for the compliments guys. I forgot about that e-brake setup, that makes life a lot easier if I elect to use an ACME adapter and a Toyota trans. This also opens up the possibility of a marlin crawler or an advance atlas T-case which is really, really cool. I'm going to find a truck scale this afternoon and weigh the Disco. A stock truck supposedly weighs 4450 lbs or so, but I wonder what the actual number is with the bumper, roof rack and wheel/tire combo and my fat arse in it.

Does anyone have an exact weight of ALH or AHU with accessories?

The other thing I have been mulling over is cost, not the cost of the parts and labor for the swap but the actual cost of the whole project vs the breakeven point. Money is not an issue. I have the finances to build it right, and sort out any teething issues but that doesn't mean I want to waste resources on futile efforts. There are a lot of qualitative benefits to the swap, but I want to figure out how long it will take to get to the breakeven point.

If someone could check my math I'd appreciate it (Frank).
My fuel tank holds 18 gallons. Gas here in San Diego fluctuates between $3.60 and $4.00 a gallon. Diesel costs between $3.90 and $4.40 a gallon. I’m basing my calculations around today’s costs, but the cost difference per gallon stays about the same between gas and diesel (around $.40/gallon).

$3.60 x 18 = $64.80 to fill the tank with gas.
$3.90 x 18 = $70.20 to fill the tank with diesel.

Gas range is a nominal 220 miles per tank averaging 12mpg
Diesel range is anticipated to be 396 miles per tank averaging 22mpg

212 miles / $64.80 = 3.27 miles per fuel dollar
396 miles / $70.20 = 5.64 miles per fuel dollar

That equals an additional 2.37 miles per dollar spent on fuel with the diesel swap. If I spend $10,000 on the swap, it will take roughly 23,700 miles to reach the breakeven. Any additional mileage will be a bonus. I do plan on putting a lot of miles on the truck going to different places throughout the west half of the country.

for me mileage is just the icing on the cake (althought it's thick icing made with real butter, and powdered sugar) ....build it for the torque the sound the coolness and the satisfaction ...I personally think you'll get in the high twenties mileage....I can get 35mpg in my tacoma if I keep it in the sweet spot between 45 and 60mph but I average 27-29 for both interstate above 65mph and in town stop and go....not 100% sure on the weight of the ALH but I think it's somewhere around 375 lbs fully dressed with all accessories ..... again...the rover is a super cool truck if you take away of all the BS failure prone electronics and the pig motor...def a solid chassis all the way

Jim have you ever thought about weighing your tacoma?

Easiest way is to use the bmw 2.4 turbo diesel available in the 524td 84-87 or the Lincoln continental- Mark 7 of thst vintage. Both came with the zf 4hp 22 trans. In your case you would need to use the 87, 88 non electronic range rover transmission and xfer the diesel bellhousing and torque converter. Very smooth and quiet engine. And easy wiring hookup. Mechanical injection pump.

And technically not legal due to age of motor