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No 6



Member Since: 03 Jul 2018
Location: West Sussex
Posts: 62

United Kingdom 1994 Defender 90 300 Tdi CSW Coniston Green
Defender 90 300tdi to 3.5 V8

Hi All

I know most seem to go the other way but my 300tdi is needing a rebuild and I plan on doing it myself, I'm in no rush and always wanted a V8 so thought I would run one for the next couple of years to scratch the itch. I've picked up a rebuilt 3.5 SU carb V8 engine to put in.

Its a 94 County with R380 manual box and I've been reading up on the requirements to get the V8 in, mainly about engine mounts and where the engine sits in the bay. Am i right in thinking the following?


1 I need a rover V8 SD1 bell housing and this will allow fitment of the V8
2 The mainshaft and spigot bearing require changing for the V8
3 Engine mounts required, can the 300tdi ones be left in situ or do they foul anything?
4 Is there a bolt on mount to covert the existing 300 mounts to take the V8?

I will be putting the 300tdi back in a couple of years (maybe!) but I want to hold on to it as it's the original engine.

Can I use the 300tdi rad and are any other bits transferable?

Cheers

Thumbs Up

Post #769349 20th Apr 2019 3:16pm
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htb2



Member Since: 02 Nov 2018
Location: aberdeenshire
Posts: 156

Scotland 

How about a discovery 1 bellhousing and input shaft asI took one out of my 3.9 Disco withR380 g/box, they should be readily available.

Think you will have to cut mounts off chassis as they will foul exhausts and weld on v8 ones.

I have an adaptor plate to fit a tdi to v8 bellhousing from ashcrofts, also got a zeus bellhousing to fit a tdi to lt95 gearbox, both of which are no use to you. Sorry

Post #769413 20th Apr 2019 9:51pm
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oneten110



Member Since: 02 Jul 2011
Location: Wish I was still in France
Posts: 738

United Kingdom 

The rad for a v8 is different, it is a full width unit. Not only that but it has 2 additional connections at the top right hand corner. One for the flow to the expansion tank and the other for the inlet manifold. It is not a Defender, it is a One_Ten

Post #769493 21st Apr 2019 8:21pm
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No 6



Member Since: 03 Jul 2018
Location: West Sussex
Posts: 62

United Kingdom 1994 Defender 90 300 Tdi CSW Coniston Green

Thanks both

It seems I might of hit a stumbling block and need some advice.

The engine is apparently a pre SD1 V8 and I'm now a bit lost. I can pull out of the purchase and lose a small deposit but is this a done conversion and what issues does this throw up?

Getting a bit worried now!

Cheers

Post #769494 21st Apr 2019 8:30pm
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Widget



Member Since: 04 Feb 2010
Location: Hungerford
Posts: 330

United Kingdom 1988 Defender 90 V8 Petrol ST Tamar Blue
Re: Defender 90 300tdi to 3.5 V8

Just a few thoughts in line below...

1 I need a rover V8 SD1 bell housing and this will allow fitment of the V8

All V8 bellhousings will fit the engine, The back of a pre-SD1 engine is the same as a later one. But the Sd1 bellhousing won't fit your gearbox. Another approach is required... either a D1 V8 bell housing from 94 onwards or RR classic V8 from similar era. The bellhousings are an increasingly rare commodity, ashcrofts produce a LT85 converted bellhousing to fit the R380/V8.

As an alternative you could fit an Lt77 from a range rover classic or per-94 V8 disco. It'll fit with some different gearbox mounts. The set-up is more readily available. The LT77 will sit in the same spot as the R380 so your propshafts will still fit.

2 The mainshaft and spigot bearing require changing for the V8
Yes - if you're handy it's doable. Its a lot of work to do and then undo in 2 yrs time though.

3 Engine mounts required, can the 300tdi ones be left in situ or do they foul anything?
As said - slap bang plumb where the V8 exhaust downpipes are.Cut off, leave some metal - then weld back on in 2 yrs time.

4 Is there a bolt on mount to covert the existing 300 mounts to take the V8?
The Land Rover OE mounts will bolt on.

I will be putting the 300tdi back in a couple of years (maybe!) but I want to hold on to it as it's the original engine.

Can I use the 300tdi rad and are any other bits transferable?


Fuel tank is fine - you'll need a RRC EFi V8 pump, pipes, filter.
Rad from 300tdi too small - remove and fit a V8 rad.
Exhaust - don't know.

Just a thought though. Emissions: will a 1994 car with carbs get it below the emissions level required? I'd go and do some more research on this.

My sense is that if this is a short term thing - don't do it. If its a forever car, do it but do it properly and fit a better, later V8 from a post 1994 Disco 1. Jonathan
@Lodelaner
1988 Ninety 3.9 V8

1951 Series 1 80" | 1972 Series III 2.25d | 1974 Range Rover 2dr V8 | 1988 Ninety CSW V8 (factory) | 1998 Defender 50th Anniversary V8 | 1996 Discovery 1 3.9 V8 | 2004 Defender 110 Td5 XS | 2006 Discovery 3 | 2008 Freelander 2

Post #769496 21st Apr 2019 8:48pm
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No 6



Member Since: 03 Jul 2018
Location: West Sussex
Posts: 62

United Kingdom 1994 Defender 90 300 Tdi CSW Coniston Green

Widget - Thank you.

That's exactly what I wanted to know and think I might have to take the hit and lose the deposit.

It is a forever car and a bit of fun, the idea being to rebuild the existing 300tdi and learn while I do it slowly over time. None of the conversion seemed to permanent and I do like a V8.

May I ask one more question, on the Pre SD1 engines, is it possible to fit EFI or interchange spares with the SD1? I understand the heads are different pre SD1 and valves smaller etc.

Reading up there are other differences too, to the oil pump, distributor etc.

Thanks again for giving such a detailed response.

Cheers

Chris

Post #769504 21st Apr 2019 9:17pm
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Widget



Member Since: 04 Feb 2010
Location: Hungerford
Posts: 330

United Kingdom 1988 Defender 90 V8 Petrol ST Tamar Blue

There are many differences, some subtle - most an incremental improvement.

Personally - for what you're trying to do I'd leave well alone - there's no point trying to fit the EFI kit to a non-EFI engine when there are plenty about with all the bits fitted and ready to go (with some fettling).

Why not whip your 300tdi out, fit a fair running engine from a scrap disco and rebuild your original 'matching numbers' Defender engine at leisure? Jonathan
@Lodelaner
1988 Ninety 3.9 V8

1951 Series 1 80" | 1972 Series III 2.25d | 1974 Range Rover 2dr V8 | 1988 Ninety CSW V8 (factory) | 1998 Defender 50th Anniversary V8 | 1996 Discovery 1 3.9 V8 | 2004 Defender 110 Td5 XS | 2006 Discovery 3 | 2008 Freelander 2

Post #769509 21st Apr 2019 9:24pm
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Trebro



Member Since: 28 Jan 2016
Location: Hampshire
Posts: 205

United Kingdom 2009 Defender 130 Puma 2.4 HCPU Stornoway Grey

I have a 90 with a 300 tdi which I'm toying with the idea of converting to v8 too, however I also have a 110 with a factory v8 (on carbs obviously).
My point is the v8 in the 110 is lovely and smooth, sounds fantastic too, but doesn't get close on the performance of the 300 tdi, it's not a daily driver, will rarely tow heavy loads so it's not a problem, but if I'm going to the trouble of fitting a v8 (and can't justify ls3 type send) I assume my best route for Bang for Buck I should be looking for a 3.9 from an early disco before they went serpentine belt with immobilisers and such like, am I correct on this assumption?

Post #769516 21st Apr 2019 9:39pm
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GREENI



Member Since: 22 Aug 2010
Location: staffs
Posts: 9331

United Kingdom 

It is a heap of trouble, to eventually take it back out.
When you rebuild the tdi, just buy a v8 90, then sell it on, I'm sure you won't lose money.

@ trebro, agreed. If you want an efi v8, get an old one, D1 / RRC for eg...I threw mine away...they're that cheap! instagram @v8_scumbag

Post #769521 21st Apr 2019 9:59pm
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No 6



Member Since: 03 Jul 2018
Location: West Sussex
Posts: 62

United Kingdom 1994 Defender 90 300 Tdi CSW Coniston Green

Thanks Widget and all. It’s my lack of knowledge on the V8 front that’s got me on the back foot. The engine I’m looking at is fully rebuilt and running with a slightly up rated cam and Su’s.

It’s a weekend car at best and about to have a rebuild. I’ve amassed everything I need.

Aside from the EFI, (wasn’t planning too), my main concern is the pre SD1 aspect. It’s a good engine I know that, basically zero miles since rebuild but is the pre SD1 a problem or can it be fitted with the same considerations as any RRC or DIsco V8? Is the RRC and disco 1 V8 an SD1 or am I totally lost?!! Embarassed

I’m green on V8 engines as you can probably gather and don’t want to commit to the wrong V8. Ive read a lot and there’s so much personal opinion, the 3.5 has thicker bore liners the 3.9 is just a bored out 3.5 and has liner issues, they both have there own issues etc. I’m sure there are better V8’s I don’t want to get a pre SD1 if this is going to cause me issues in getting spares or gives me any conversion issues that are above and beyond what a disco or rrc v8 would give if that makes sense?

Post #769535 21st Apr 2019 11:05pm
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Widget



Member Since: 04 Feb 2010
Location: Hungerford
Posts: 330

United Kingdom 1988 Defender 90 V8 Petrol ST Tamar Blue

In simple terms any V8 will fit. Sourcing a nice V8 engine for a good price and dropping it in onto new mounts is the easy part of a conversion.

As said the challenge is the faff of changing/modifying and then undoing the other changes required.

It's the gearbox, chassis engine mount points, different bellhousing, exhaust, fuel system, emissions compliance, cooling, native electrics that take time, money and your frustration - and all will need undoing.

All doable - however do not underestimate the job. Believe @Greeni - he's an experienced and seasoned V8 converter who spends many hours fitting stuff, then driving it down the road before deciding to take it all out and do it better - he is the voice of experience!

Good luck with whatever you decide to do. Jonathan
@Lodelaner
1988 Ninety 3.9 V8

1951 Series 1 80" | 1972 Series III 2.25d | 1974 Range Rover 2dr V8 | 1988 Ninety CSW V8 (factory) | 1998 Defender 50th Anniversary V8 | 1996 Discovery 1 3.9 V8 | 2004 Defender 110 Td5 XS | 2006 Discovery 3 | 2008 Freelander 2

Post #769561 22nd Apr 2019 9:14am
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oneten110



Member Since: 02 Jul 2011
Location: Wish I was still in France
Posts: 738

United Kingdom 

I have done the conversion from V8 to Tdi and then gone back to V8. There is a lot of work involved, none of which is difficult but it is still work. The R380 and LT77 are dimensionally the same and the gearbox mounting are bolt on items so no difficulties there. The engine mounts are a pain but if you can weld not that difficult. The electrics are a doddle, even if you decide to fit an EFI set up.
The elephant in the room is the cost, of all the necessary bits required, even without the cost of the engine. Plus you will be replacing your diesel with an engine that does half the MPG, if you drive like a saint, has broadly similar performance and doesn't like getting wet. Only to undo it all in a couple of years time.
For the amount of money involved, I would get a replacement Tdi from Turner engineering.
Www.turnerengineering.co.uk It is not a Defender, it is a One_Ten

Post #769573 22nd Apr 2019 10:47am
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No 6



Member Since: 03 Jul 2018
Location: West Sussex
Posts: 62

United Kingdom 1994 Defender 90 300 Tdi CSW Coniston Green

Thanks again all, I'm aware of the other aspects of the conversion and as I said, weekend car at best so fuel economy isn't an issue.

The emissions situation is interesting, I read that the car will be tested on the model itself if the engine is older than the car but if the engine is newer then the test will relate to that.

I could well stay with the V8 and keep the original 300tdi to rebuild at a later date but given the feedback and sheer arseness of the process I may well swerve it altogether.

Shame I don't have the room or money for a V8 90 or else I would buy one.

Post #769607 22nd Apr 2019 4:04pm
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diesel_jim



Member Since: 13 Oct 2008
Location: hiding
Posts: 4814

United Kingdom 2006 Defender 110 Td5 SW Epsom Green

I used a turboD radiator (not Tdi.... the earlier indirec injection one). with different unions fitted the oil cooler (I had a 3.9EFI) pipes fitted straight on.


IIRC the bottom hose also did, but the top one needed bodging...

Post #769763 23rd Apr 2019 8:32pm
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