Ex military 90 soft top 1994 - 300TDi conversion

Hi all, I have just purchased a 1994 ex-military 90 and am having more and more questions I was hoping for some help on!
Oringinally a 2.5 NA, but has been converted to a 300TDi at some point in the past. Didn't know much about this till I discovered the engine sitting a few inches futher back so none of the coolant hoses fit. That part is fine as can use extended ones.
My questions are:
It has a cone shaped air filter to the right of the engine (looking into the enging bay from the front) - would a standard cylindrical air filter box mount to the left of the enging considering its closer to the bulkhead?
The viscous fan is clipping the steering box - any spacers I can use to move it forward a little?
Front prop shaft missing, any way to identify correct prop shaft to considering the transfer box will be in different position to original?
The gear/transfer sticks are way far back, probably 9 inches and a section cut out of the seat box for this. Is this likely an enging/gearbox from a disco? What could I do to move sticks forward as preferably want a centre seat added.
many thanks

UPDATE: to clarify it was bought as a project vehicle to work on with my eldest in the run up to his driving age. I've previously restored a 300Tdi 110 hard top. Was aware it had been changed to a 300TDi (and liked the sound of it over the 2.5NA) but didnt appreciate it was mounted a few inches back on the 2.5NA chassis. I've also got the the original 2.5NA and an additional 300Tdi engine on pallets so have the option of reverting back to original if the position causes too many issues.
I knew the prop shaft was missing..... its been sitting in a shed since the last MOT expired in 2019. Last advisory 'Front Propshaft universal joint worn' (And 'Vehicle structure has slight corrosion n/s and o/s floor (6.1.A.1)' )

Rincewindy said:

Hi all, I have just purchased a 1994 ex-military 90 and am having more and more questions I was hoping for some help on!
Oringinally a 2.5 NA, but has been converted to a 300TDi at some point in the past. Didn't know much about this till I discovered the engine sitting a few inches futher back so none of the coolant hoses fit. That part is fine as can use extended ones.
My questions are:
It has a cone shaped air filter to the right of the engine (looking into the enging bay from the front) - would a standard cylindrical air filter box mount to the left of the enging considering its closer to the bulkhead?
The viscous fan is clipping the steering box - any spacers I can use to move it forward a little?
Front prop shaft missing, any way to identify correct prop shaft to considering the transfer box will be in different position to original?
The gear/transfer sticks are way far back, probably 9 inches and a section cut out of the seat box for this. Is this likely an enging/gearbox from a disco? What could I do to move sticks forward as preferably want a centre seat added.
many thanks

Click to expand...

Put up some pictures of the areas you describe, Everyone likes [pictures, but will help us see what you are talking about.

For a 300tdi the air filter should be on the left as you face the engine but if the engine is sitting further back it may not fit. As long as your current intake system is sealed and has a filter I would put this to the bottom of the list and deal with other issues first.

I do not think you can move the viscous fan forward. But i would also stress that a viscous an is very little use without a fan cowl around the radiator to focus the air flow. so even if you get the fan to clear it is unlikely to be doing much for cooling. A lot of people (myself included) run electrics on engine conversions. I have the twin fan pack form an aircon Mondeo fitted to mine with an x-eng coolant pipe fan switch

The prop shaft should be standard as the transfer box mounts will be in the same place as the original even if different gearbox and engine. But to confirm just ensure the length between the yoke of the diff and the yoke of the transfer box.

From your description it wounds like you have a discovery gearbox fitted. I believe the gearboxes are the same but the linkage is different, I am not an expert however. I think you can either fit a defender gearbox or fit the linkage from a defender gear box to your existing gearbox. Depending on how the current one is fitted there may be a fair amount of repair work required to the seatbox to get that back to standard.

Rincewindy said:

Hi all, I have just purchased a 1994 ex-military 90 and am having more and more questions I was hoping for some help on!
Oringinally a 2.5 NA, but has been converted to a 300TDi at some point in the past. Didn't know much about this till I discovered the engine sitting a few inches futher back so none of the coolant hoses fit. That part is fine as can use extended ones.
My questions are:
It has a cone shaped air filter to the right of the engine (looking into the enging bay from the front) - would a standard cylindrical air filter box mount to the left of the enging considering its closer to the bulkhead?
The viscous fan is clipping the steering box - any spacers I can use to move it forward a little?
Front prop shaft missing, any way to identify correct prop shaft to considering the transfer box will be in different position to original?
The gear/transfer sticks are way far back, probably 9 inches and a section cut out of the seat box for this. Is this likely an enging/gearbox from a disco? What could I do to move sticks forward as preferably want a centre seat added.
many thanks

Click to expand...

tbh, I'm amazed how anyone can buy a vehicle and know nothing about it. Missing front prop? Sounds like an utter bodge job tbh. If you knew all the issues before your purchased and how to fix them, then maybe it could represent a bargain. I truly hope you paid a pittance for it. But based on your questions, I'm guessing you don't really know what has been done to the vehicle, why or how you'd go about fixing them properly.

For some odd reason, ex-mil models go for a premium these days, despite them generally being the worst spec for road use. You might be better off just selling on and buying something in the condition you actually want.

BTW - not trying to be be unhelpful.

But anything heavily modified, could be a minefield unless you have some knowledge and are prepared to do lots of work and spend money. There are also a million ways to modify a vehicle. So without seeing or knowing exactly what has been done, it might not be easy to figure it all out and may well require rectifying work or other bespoke mods to get it to work.

If you didn't mean to buy a project vehicle needing loads of work. I'd still suggest selling it on might still be the most sensible approach.

For the record, if the engine is in a different location that is not a factory location. Then all items will need modding to work, be it exhaust, props, hoses, oil pipes, intake pipes and so on. And you'll need to bear in mind this will be on going.

If the engine and gearbox have been moved to a non factory position, then it sounds like it may have been a poor/lazy conversion. So you might also have to question the condition of other parts of the vehicle too.

For reference, the 200Tdi was fitted with a different setup in the Discovery and Defender. But you can physically drop a 200Tdi in place of a 2.5 Nad/TD engine and keep the rest of the drivetrain. This won't match the factory 200Tdi location, but does work with a bit of fettling.

When the 300Tdi was introduced, the fitment was the same in the Disco and Defender. However, the engine location (and gearbox) will be different to earlier 90/110 models. I believe Steve Parker did a kit for a 300Tdi, but I've never looked into it and they have now ceased trading. The 300Tdi uses a different gearbox, as well as a different seat box and transmission tunnel to the earlier models.

If you can figure out what has been done (or not done), you could sauce all the parts and likely sort the vehicle out. But it might get pricey and need a lot of work. Else you are likely going down the route of quite a few bespoke components.

Are you in the UK? If so, there is lots of choice of other Defender vehicles available. That may well be a huge amount less effort and money to have in good running order.

dag019 said:

Put up some pictures of the areas you describe, Everyone likes [pictures, but will help us see what you are talking about.

For a 300tdi the air filter should be on the left as you face the engine but if the engine is sitting further back it may not fit. As long as your current intake system is sealed and has a filter I would put this to the bottom of the list and deal with other issues first.

I do not think you can move the viscous fan forward. But i would also stress that a viscous an is very little use without a fan cowl around the radiator to focus the air flow. so even if you get the fan to clear it is unlikely to be doing much for cooling. A lot of people (myself included) run electrics on engine conversions. I have the twin fan pack form an aircon Mondeo fitted to mine with an x-eng coolant pipe fan switch

The prop shaft should be standard as the transfer box mounts will be in the same place as the original even if different gearbox and engine. But to confirm just ensure the length between the yoke of the diff and the yoke of the transfer box.

From your description it wounds like you have a discovery gearbox fitted. I believe the gearboxes are the same but the linkage is different, I am not an expert however. I think you can either fit a defender gearbox or fit the linkage from a defender gear box to your existing gearbox. Depending on how the current one is fitted there may be a fair amount of repair work required to the seatbox to get that back to standard.

Click to expand...

Thanks for the info, that makes sense as it came with an electric fan and I see something like an x-eng coolant pipe switch so must have been for that!
Have added a picture of the inside, most is stripped down now as i need to weld the new footwells in. Will have a look and see what gearboxes I can get. Will measure the diff yoke - transfer box yoke this weekend

This isn't the same as yours I know but given they share similar heritage, there may be a few shared design cues (unless it was all made up with whatever was in the shop).

My Tithonus TUM FFR (Defender 110) came with a 200TDi Disco engine (which also sits further back) with a short R380 gearbox and a LT230 1.667 transfer box (some were fitted with the 1.4).

The turbo's definitely been clocked which is a Glencoyne thing and the exhaust manifold is definitely a Steve Parker bit of kit. I've no idea on axles, diffs & props though, sorry.

That makes me sound like I know what I'm talking about but I'm just parroting what Tom told me down near Tain at D and M LR Spares.

R380 stumpy box exists to allow as a direct fitment (mostly) for an LT-77. This was done to allow warranty claims on LT-77's after production stopped.

1.6 transfer box was usually only on military 110's and with a Tdi will give way too short gearing to be useful.

200Tdi will fit in the same location as a 2.5Nad or 19j TD, which is the rearward position, close to the bulkhead. But the fan will interfere with the steering box. And all pipe work will be custom.

In 99% of cases, you can stick with the stock Defender front driveshaft when running a 300TDi with an LT230, since the transfer case sits pretty much where it does on a 2.5NA setup. That said, it’s always a good idea to measure the actual length from the front diff flange to the transfer case flange. If you’ve pushed the engine and gearbox back but left the transfer case in the stock position, the factory shaft should still do the trick.