200Di - frequently asked questions


"The 200DI conversion you did is working brilliantly. Its completely transformed the vehicle and I'm incredibly happy with the work you have done." - JC, Herts

"I have just returned from a 600 mile trip in my Land Rover 109.   It didn’t miss a beat!  In fact, it performed far beyond my expectations.  The noise and vibration have been well controlled by the Wright Off Road inside kit and the under bonnet acoustic trim.  The noise and vibration are both, in general, much better than I had expected and, certainly, way better than your original demonstrator.   At 55 mph the loudest noise is wind noise and the cross ply MT tyres...  The vehicle is certainly quite a lot faster in both acceleration and top speed than my old 2.25 petrol engine, even with its stage 1 head.  It is also more driveable, with oodles of torque (an issue with the 2.25 petrol and the stage one head).   It feels as if it would cruise all day at 60, though I tend to stick at 55...  As to the crucial question of fuel consumption, running empty, on mixed roads and cruising at 50/55 mph on the outward journey (300 miles) I returned a measured 35 mpg.  On the return journey – with well over half a ton in the back – I got a measured 33 mpg.   Brilliant!!  Thank you for a job really well done." - JH, London

"Another endorsement!  I have just come back from a further 400 mile round trip - fully loaded with well over 3/4 ton of paper.  With any 'old' Land Rover diesel this would have meant 45 mph and slowing to a crawl uphill. This 200di engine still accelerates the 109 UPHILL at 50 mph in top gear.  Amazing. It also returned about 32 mpg - measured brim to brim."  - JH, London (again)

"Just a few words to say the run home with the new engine was great it did not miss a beat...  I was pleasantly surprised with turn of speed  most of journey home at 50 with the odd run up to 55 there seemed plenty of power there to me if needed, more than happy with that."  - KS, Essex


Judging by the number of calls and emails I get, there must be a fair few 200Di conversions on the road by now.  I have put together some answers to the most common questions and problems, and will add to this section from time to time.

Within the DIFAQ I have tried to group together questions on related topics.

1. Will it fit?

Series One - probably a drop in fit for a 1957/58 2.0 diesel, but there aren't that many about.  The Series One had a different bellhousing bolt pattern to later vehicles.  If you are replacing a Series One engine, you will have to swap the gearbox bellhousing for one from a Series Two, and modify the engine mounts on the chassis so that the mounting rubbers sit flat on them.

Carawagon / Dormobile / Marshall Ambulance / Series II Forward Control - it will physically fit, but you might find yourself wishing you had spent the extra time and money on a 200TDi.  The main problem on the big-bodied vehicles is going to be wind resistance, which will make high speed cruising a bit difficult.  I have done several plain 109 Station Wagons with no problems, but my feeling is that a standard 109 SW is at the upper end of what a 200Di can drag around and still be able to keep up with the traffic.  I would be interested to hear from anyone who has DI'd a Carawagon or similar.

109 V8 (Stage One) - not a chance.  The TDi flywheel housing has a recessed flywheel, the V8 doesn't have a flywheel housing at all.  So even if you can persuade the LT95 bellhousing to bolt up to the TDi, the input shaft splines won't engage with the clutch plate.  You might be able to fit a 300TDi with an adaptor plate - it is on my 'to do' list of things to try.

90/110 - yes, but why would you?  Fitting a TDi with turbo to a 90 or 110 is really no more difficult than a 200Di - it is all bolt-on stuff.  The 90 and 110 are heavier and higher geared than a Series vehicle, have stronger transmissions and better brakes.  I can see no reason not to fit the turbo and intercooler.

2. What do I do with.......

Pipe from turbo to injection pump - remove the banjo bolt on the injection pump, remove the pipe and discard.  It might be worth finding a rubber plug or similar to replace the banjo bolt - you don't want mud and water getting into the pump body.

Vacuum pump - if you have a vehicle without a brake servo, just plug the hose on the top of the pump with a bolt or similar.

3. Noise / vibration issues

Vibration transmitted through engine mounts - the OEM Defender mounts that I sell through my web shop seem to be the best at isolating vibration, but the 200TDi is a pretty rough engine however you mount it.  My friend Ray spent a lot of time grafting the giant Discovery engine mounts onto his Series 3, and it still buzzes and rattles.

Noise - I have experimented with soundproofing in a couple of customer vehicles.  Much of the noise you hear in a Series vehicle is actually reflected off the roof, doors and hard top sides.  You will get some big improvements for little money by lining the roof (I have used an old Defender hard top headlining and foam tiles to good effect), hard top sides (13mm acoustic foam, sold as "L foam" by Noise Stop Systems ) and door bottoms (hardboard panels with loft insulation stuffed behind them).  You can also line the footwells, firewall and front face of the bulkhead with acoustic foam, but the improvement isn't so great.  Lining the underside of the bonnet with sound absorbing material seems to make a worthwhile difference - just make sure the material you use is heat and flame resistant.  The rubberised engine cover found on later Discos doesn't seem to make a huge difference.

Beyond this try lining the sides and floor of the rear tub with rubber matting, line the back door the same way as the fronts, and a Wright Off Road floor matting kit is well worth the money even at £250.

4. Injection pump adjustment

Most of the conversions I have done have worked straight out of the box with no fiddling required.  But I have had a small number which have been down on power, excessively smoky, or both.  Usually the cause turns out to be mechanical - duff injectors or pump.  But I am starting to see an increasing number of TDi engines where the pump settings have been played with.  It isn't usually difficult to spot as the full power adjustment screw has a locking wire through it, and if this is missing then you can be sure someone has been fiddling.  Either the fuelling has been turned down to get through the MoT emissions test, or (more commonly) turned up in search of more power.  So if your engine feels a bit gutless, or is very smoky, it might be worth tweaking the full power adjustment screw slightly to see if it makes any improvement.  Don't overdo it, the adjustment is pretty sensitive - I find there is only about half a turn between too much fuel and not quite enough.  And if your engine is running fine, don't be tempted to tinker with the pump - you'll probably make it worse.  If you Google "Bosch VE pump adjustment" you will find a wealth of information on these injection pumps.

I am also seeing a few pump failures in both 200Di and 200TDi engines.  Symptoms include a bad misfire with lots of light coloured smoke from around 1500 rpm upwards, or thick black smoke and lack of power at full throttle.  I have had some of the suspect pumps to bits and there is no obvious pattern - couple of broken springs (a common Bosch VE failure) and more worryingly, pumps with major internal corrosion.  An injection pump is full of diesel and should not corrode internally.  I suspect the cause to be badly-processed waste vegetable oil (chip fat).  Used chip fat has a very high water content and needs to be properly purified before it is used in vehicles.

5. It won't work because.... A special section for the unbelievers - the people who have taken the time to explain to me (usually via Internet forums) why they know the 200Di conversion won't work, even though they haven't driven one.

    "It's a turbo engine, so the compression ratio will be too low." 

The CR of the 200TDi is 19:1, compared with 21:1 for the old 2.5 non-turbo (12J), which is probably how this myth originated.  But the 19J turbodiesel also has a 21:1 CR.  The reason the TDi has a lower CR than the older engines is down to more efficient direct injection and a better combustion chamber shape.  The Ford Transit 2.5 Di engine, which has the same injection system and similar combustion chambers, also runs a 19:1 CR in non-turbo form.

    "It will overfuel and smoke really badly without the turbo."

On-boost fuelling is controlled by the boost valve.  This sits on top of the pump and is connected to the turbo by a pressure line.  The boost valve increases fuelling in response to boost pressure.  No boost pressure, no extra fuelling.  Simple when you think about it.  I have never had a problem getting a 200Di through an MoT smoke test. 

    "If you want to keep things simple, why not keep the turbo and leave off the intercooler?"

If you do that you will have to adjust the boost fuelling.  The intercooler works by making the air cooler and therefore denser.  This allows more fuel to be added.  Without the intercooler I suspect that the boost valve will overfuel the engine under load, resulting in black smoke.  But there is plenty of information on the Internet on adjusting Bosch VE injection pumps - try http://tinyurl.com/couejq for a good starting point.  A non-intercooled TDi might make sense for more heavily laden Series vehicles - perhaps I will try building one some time.  You will still need a custom exhaust, and it would probably be a good idea to retain the oil cooler, but the turbo manifold plumbing will be a lot simpler. Many manufacturers offer intercooled and less powerful non-intercooled versions of the same engine, so it wouldn't be a radical step to try a non-intercooled TDi - perhaps call it a 200TD.

    "It will be really slow.  I know because I've driven a Disco with a failed turbo, and that was slow."

I'm sure it was.  After all, a Disco 1 is about 50% heavier than an 88 inch Series vehicle, much higher geared, with more rolling resistance from the permament 4wd.  And of course a Disco is intended to offer car-like levels of performance and refinement, and only just manages to do so on 111 bhp, so if you lose some power you'll really notice the difference. It's not really the same kind of vehicle as a Series II or III, is it? I'm not saying that a 200Di is as fast as a TDi.  Of course it isn't - it's probably got around 30-35% less power.  But if you are happy with the performance of a good standard 2.25 petrol, you'll be just as happy with a 200Di.  If you are running a 2.25 diesel or an old tired 2.25 petrol with worn bores I can guarantee you will feel the difference - in both performance and economy.  And if you do the 200Di conversion and then feel you need more power, just put the turbo back on (along with the intercooler, oil cooler and a free-flowing exhaust).

    "If you want a non-turbo engine, why not just fit a 2.5 diesel from an old 90 or 110?"

Fair question, but I reckon the 200Di makes more sense than the old 2.5 N/A, and here's why.  Firstly, to fit a 12J diesel (from a 90 or 110) to a Series vehicle you need to cut and weld the offside engine mounting on the chassis, as the 12J has a low-mounted injection pump and will foul the chassis.  No great problem if you can weld to a reasonable standard, but not ideal if you have a nice new galvanised chassis, and it can be tricky to get the modifications exactly right so that the engine sits level in the chassis.  There is another version of this engine, the 15J (ex Sherpa 300 van) which has a high mounted pump, but this one doesn't have a sealed timing cover which makes it less than useful for off-roading. And timing belts for the Sherpa engine are now almost impossible to find.  In any case, whether 12J or 15J, both have the same fuel injection, cylinder head and combustion chamber design as the old 2.25 diesel.  So although significantly more powerful than a 2.25 they still aren't going to be as good as an engine with direct injection, either in terms of throttle response or fuel economy.

    "The 200TDi engine was designed as a turbo engine, so you shouldn't take the turbo off."

A while ago I met one of the R&D engineers from an external contractor who had worked on the fuel injection for Project Gemini, as the 200TDi engine was known inside Land Rover.  He told me that his company was supplied with both turbo and non-turbo versions of the Gemini, and managed to get both versions performing to Land Rover's satisfaction.  For some reason the non-turbo variant never made it into production.  I am guessing that it was intended for Third World export market Defenders, and by 1990 that market just wasn't big enough for Land Rover to justify a separate engine variant.  Or possibly the new EU diesel emission rules just coming in at that point made it uneconomic to develop and get type approval for an engine variant that would not have been a big seller.  I don't know how close Land Rover's own 200Di got to production, but the Microcat electronic parts book provides a small clue.  Under the 2.5 N/A engine parts section is a drawing intended to show the turbo feed and return blanking plugs fitted to late 2.5 N/A engines, which used the same block as the 2.5TD.  But the drawing very clearly shows a Gemini (TDi) block with turbo blanking plugs.  So it looks as though Land Rover at least made a start on producing a parts book for the proposed non-turbo Gemini.  I suspect there is an interesting story out there waiting to be told.


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