200/300TDi into Defender - some useful information

Guide for DIY fitting - by Glencoyne Engineering



Questions and problems

A few questions I am commonly asked about these conversions, and one or two problems you may come up against.


I have an old Discovery 300TDi which has failed the MoT.  Can I use the engine from that?

Yes, but you will need to weld new mounts onto the chassis among other things.  Click here for more details.

A factory-built Defender 300TDi has the engine sitting a lot further forward than the 200TDi.  This was so that the Disco and Defender could use the same engine rather than making two different versions.  To convert to 'factory' 300 spec you will need to change the gearbox, seatbox, floors, transmission tunnel, propshafts and gearbox crossmember as well as sorting out the engine mounts. It is all technically possible, but not worth the hassle while 200TDi engines are still fairly easy to obtain.


Can I use the gearbox from the Discovery?

No.  The input shaft and bellhousing are longer, and the gear lever will come up through the middle of the seatbox.


Can I use the Discovery transfer box to raise the gearing?

Yes.  Most Defenders have a 1.410 ratio transfer box - some early vehicles and military 110s have a lower 1.6 ratio box which is too low geared for the 200TDi unless you are running massive tyres or towing very heavy loads.  The Disco box is 1.22 ratio. This works very well in a Ninety, giving a more relaxed cruise, but can be a bit marginal on a One Ten, especially a heavily loaded Station Wagon.  The engine will cope with the gearing but you may find performance a bit lacking.  To fit the Disco transfer box you will need to either drill and tap the holes for the handbrake bracket so you can use the Defender rod-operated handbrake assembly, or track down a handbrake cable long enough to reach from the Discovery handbrake backplate to the Defender handbrake lever.  The Defender 300TDi cable is just about long enough but ends up with quite a tight bend in it which may give problems.

Check the condition of the splines on the transfer box input gear before you think about fitting a second hand transfer box.  These often wear badly due to lack of lubrication.  The problem was eventually solved by cross-drilling a hole through the input gear, and if you are lucky your transfer box may have this fitted. But if you find dry grease and rust coloured powder around the splines, take a much closer look. The input gears are not interchangeable between transfer boxes of different ratios. although fairly cheap to buy new.


Do I need to upgrade the brakes?

No.  When Land Rover introduced the Defender 200TDi, the brakes on the One Ten were carried over unchanged.  The Ninety got the front calipers from the One Ten (with larger pistons) but I suspect that was mainly a cost saving measure allowing the two models to use the same front axle assembly.  The brakes on any Defender are plenty powerful enough if in good condition.


Is my transmission strong enough to cope with the extra power?

Land Rover made no changes to the Defender transmission when the 200TDi was introduced.  It used the same LT77 gearbox, LT230 transfer box, propshafts and axles as the lower powered models.  If there are any faults in your transmission the extra power may cause problems: all Defenders seem to get through propshaft UJs fairly regularly, and if the splines on the gearbox mainshaft and/or transfer box input gear are badly worn, using the full 111bhp will finish them off fairly quickly. But provided everything is in good condition you don't need to worry.


Do I need to notify DVLA?

Normally, yes.  If you are replacing an existing 2.5 diesel, just fill in the new engine number on the V5C and send it off.  If there is no engine number on your V5C then I wouldn't bother notifying the new one.  If you are replacing a petrol engine you will need to notify change of fuel type (heavy oil), and if replacing an older 2.25 engine you will need the new engine size as well (2495cc).  This is where problems can arise.  I have heard of a few cases where DVLA have come back demanding documentary proof of the engine change (i.e. an invoice for the work).  If you have done the swap yourself you will not have this.  A friendly Land Rover specialist should be happy to inspect the vehicle and then give you a short report on headed paper confirming the engine number, size and fuel type, in exchange for some beer tokens.  This should be enough for DVLA. 

There are rumours circulating that DVLA are going to start asking for the identity of the donor vehicle from which the engine was taken.  I haven't heard any examples yet of this actually happening, but something to bear in mind when sourcing your engine. I will be very interested to hear from anyone who has had problems with DVLA after fitting a 200TDi.

Remember to tell your insurers about the engine swap as well.  Some of the big companies can be a bit funny about engine swaps. I have always found NFU Mutual to be very good.


Common problems:

Unable to bleed fuel filter.  There is a 10mm headed bleed screw on top of the filter and a priming lever on the side of the pump.  The priming lever will only work properly when the actuating lever inside the pump is in the correct position on the camshaft.  If the lever moves with no resistance, turn the crankshaft (socket on the front pulley bolt) about 45 degrees at a time and keep trying the lever until resistance is felt.  If the pump will still not supply fuel it may need changing.  This design of lift pump does not like being left unused for long periods.  You may be able to get it working by removing the inlet pipe and trickling diesel into the inlet while operating the priming lever.

Engine turns over but will not fire - usually an electrical fault. (You did bleed the fuel system at the filter, didn't you?) With the ignition on, try pulling off the spade terminal from the stop solenoid on the injection pump, then reconnecting it.  You should hear the stop solenoid click as the wire is connected and disconnected.  If no click, check that you have 12 volt supply at the solenoid.

Tried that, stop solenoid clicks, engine still won't start.  Slacken the nuts on all four injector pipes at the injectors, crank over the engine and see if fuel emerges from the unions.  Sometimes if a pump has been drained of fuel it can be difficult to get the air out.  When fuel emerges, tighten up the unions and try again.

Engine starts but smokes and runs rough.  Firstly check that all your fuel pipes are properly connected and that there is no air getting into the fuel system.  Check that all the injector pipe unions are tight. Sometimes if a TDi engine has been sitting unused for a while the pump internals seem to stick, giving a bad misfire which clears if you rev the engine a few times.  If the misfire persists you may have one of a number of faults - faulty injectors, faulty injection pump, pump timing incorrect, faulty lift pump, valve clearances incorrect, failed head gasket (usually between number 4 cylinder and one of the pushrod tubes, or at the back of the head).  Work through methodically, starting with the cheapest and easiest to diagnose faults.  Injection pump failure is not unknown on these engines, especially if they have been run on badly processed biodiesel - the water content corrodes the pump internals.


I think that covers most of the main issues.  If having read through these notes you decide the conversion is outside your abilities, click here for details of my conversion service. I must have done upwards of thirty conversions by now.

Please feel free to contact me if you spot any errors in the information or want to discuss 200TDi conversions in more detail.


200TDi guide page 1

200TDi guide page 2

200TDi guide page 3

200TDi questions and problems