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Rednaxela



Member Since: 23 Sep 2019
Location: UK
Posts: 28

United Kingdom 
300Tdi to 4.6

Hi

Recently I've being starting to decide what direction I want my 90 to go in. Very soon after selling a canvas'd SIII I decided to order a full tilt for the 90 to replace the cab/ifor canopy and now I'm thinking, to further enforce the 'fun second vehicle' vibe, perhaps put a v8 into it.

The 300Tdi is good and the 1998 vehicle is completely factory spec so will need to think this through quite a bit but to help that I'd like an up to date view on what will work?

I wouldn't skimp or try to get it in as quickly as possible but don't want to hack the vehicle about too much.

I'd want to use a 4.6 (not Thor) with megasquirt
And presume I can bolt on a R380 v8 bell housing from Ashcrofts, if they still have one.
Fit a fuel pump to the underseat tank
New radiator also?

I have looked through many threads from various years but there seems to be so much conflicting information.

Would the gearbox need an oil cooler?

How much wiring is involved?

Will this need new engine mounts welded or an adaptor used instead?


There's lots of info I need to gather up! Thanks and looking forwards to responses.

Post #872849 14th Dec 2020 1:14pm
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GREENI



Member Since: 22 Aug 2010
Location: staffs
Posts: 10115

United Kingdom 

I’ll decline to comment as i went with auto and GEMS and won’t get into a debate as why Laughing

You will benefit from v8 engine mounts and a v8 rad, also a GENUINE Bosch 044 fuel pump. instagram @v8_scumbag

Post #872863 14th Dec 2020 3:09pm
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JimC



Member Since: 22 Jan 2011
Location: NOVA
Posts: 164

United States 2007 Defender 130 300 Tdi HCPU Arles Blue

This isn’t that bad. 14CUX only uses a few wires to tie into the main harness, mega squirt might be less. You can build a stand alone harness or perhaps adapt one from a Range Rover or something. The motor mounts are different but easily done. The gearbox crossmember is not used, instead you’d need separate chassis mounts and the tubular crossmember that clears the exhaust- again, this is common to Range Rover. All that stuff just bolts on. Even though you’ve got a different length bell housing and r380, the t-case still lands in the same place so you don’t need new driveshafts.

Trans oil cooler is totally optional, only the 1193 NAS 110 (lt77) and 1997 NAS 90 (with auto trans) had them.

If you can part out an old 5-speed disco you’re most of the way there. The rad and shroud is defender specific tho.

Post #872868 14th Dec 2020 3:24pm
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Shroppy



Member Since: 25 Feb 2016
Location: Shropshire
Posts: 563

United Kingdom 1986 Defender 130 V8 Petrol HCPU Aintree Green

I'm going through this process at the moment, though my base vehicle was originally a 3.5 with LT85 gearbox, a few pointers which may or may not help;

- You can pick up a GEMS 4.6 fairly easily and cheaply, the GEMS system is excellent, I personally wouldn't go with 14CUX (lacks the refinement of later systems) or Megasquirt (expensive). I am a bit biased though as Mark Adams of Tornado Systems is a good friend of mine, he's the chap to speak to about wiring them up.

- Finding a GEMS engine with a manual flywheel is hard, there are a few 4.0 manuals about but I've not personally seen any 4.6s (doesn't mean they don't exist). I picked up a NOS flywheel from V8 developments, Rakeway also make them. Not cheap but you'd need a trigger ring of some description for MS anyway.

- As Greeni suggests, RV8 engine mounts would be a big help as it will allow you to have everything in the 'factory' position. Without reminding myself I can't remember how the transmission is supported in a 300tdi? Suspect it's the later type crossmember where the LT230 sits on square rubbers? I *think* your current props will work as the correct engine position and V8 bellhousing should mean your tbox doesn't move, could be wrong.

- You'd need to swap the pinion from your R380 to a V8 one as the spigot bearing dia. and pinion length is different, not an awful job but whilst you're going to the trouble I'd be tempted upgrade to a later Suffix K or L R380 as I suspect yours may be a Suffix J or earlier? The later (TD5) boxes were revised to include improved bearings and teeth on the layshaft(?).

- The R380-V8 bellhousing was also used in Discos so you might find a cheaper one from a breakers as opposed to buying from Ashcroft. I opted to buy a complete suffix J V8 R380 and Lt230 from a disco and swap the bellhousing, 5th gear and oil cooler over to a Suffix L box.

- As above, a gearbox oil cooler isn't necessary but its certainly not a bad idea.

- You won't be able to use the P38 headers so budget for a set of Defender fitment ones, you can probably reuse the tail section from your current exhaust if needs be.

- Radiator - probably, V8s need lots of cooling so the full width V8 one would be a big benefit. The viscous fan on a GEMS engine works well or, you could opt for electric and do away with the need for a cowling.

Happy to help if I can. You're in the right place for support. 1985 127 V8 Build Thread
Series 1 80"
Series 1 88" 4x2 Build Thread

Post #872888 14th Dec 2020 5:20pm
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Rednaxela



Member Since: 23 Sep 2019
Location: UK
Posts: 28

United Kingdom 

The information is appreciated, thank you. May boil down to whether or not - or when - I will find a unit nearby to look at. Confused

Post #873057 15th Dec 2020 3:35pm
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Hufflepuff



Member Since: 25 Oct 2014
Location: Hampshire
Posts: 562

England 2005 Defender 90 Td5 XS CSW Tonga Green

I have a similar ongoing project on the go myself Rednaxela, that being:

Rover v8
GEMS ECU with the Tornado systems chip
R380 gearbox

although I did start with a genuine 110 v8, so I didn't have to worry about changing the engine mounts.

I opted to go for 'as new' parts where possible, so Richard's chassis, remanufactured engine, and rebuilt R380 from Dave at Ashcroft, who also supplied the appropriate bellhousing.

Because of all the new parts, its cost me a small fortune. Thankfully as I am the worlds slowest mechanic (4 years now... oO) it has allowed me to spread the cost, as I would not have been able to finance it in one hit.


Sticky points have been:

Manual GEMS flywheel. Not available new - so you are looking on ebay for a second hand one from a RangeRover P38, and you can take a guess as how many manual RangeRovers there were. Having said that, I did get hold of one, and they do come up so its certainly possible - but expect to pay a lot.

Exhaust manifolds. There isn't that much room between the chassis rails, especially considering the sensors (knock and flywheel position) that sit on the GEMs engine. I originally bought a tubular manifold, but its really really right to fit it, and really requires a bit of 'denting' of the tubes to increase the clearance. I'm now trying Range Rover classic manifolds, which have much more clearance, but when you run into needing a bit more of a 'custom' exhaust system, depending on which gearbox cross member you are using. Hopefully this will not turn out to be a big problem, but its something to be aware of.


For a fuel pump, I was recommended by the engine builder (ACR) to use a standard P38 in-tank pump. I'm not sure if this is the Bosch 044 fuel pump which Greeni referred to - but it required a customer fuel tank to fit. Fortunately as I wanted a bigger tank anyway, I have had a 110 litre'ish tank made up specifically to fit this p38 pump unit. 2005 Td5 90 XS
1989 V8 110 CSW

Post #873062 15th Dec 2020 4:10pm
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Rednaxela



Member Since: 23 Sep 2019
Location: UK
Posts: 28

United Kingdom 

Hmm, I've returned to the conversion planning process with a heightened desire.

Current preference is to use a Land Rover spec ECU rather than megasquirt as some people imply that it can be pretty technical to set up. But also for a more 'factory', less aftermarket feel.

Therefore, with a 4.6 I'm concerned I may also have a bit of a headache trying to install a gems ECU.

I was wondering if I could use a 14CUX (as mentioned by Jim) with the 4.6 instead. Or perhaps an outfit like Tornado systems could modify a gems ECU to prevent it from looking for p38 specific functions when installed into the 90?

I'm also thinking about a using a 3.9 14CUX EFI, after all I know of a 3.9 with a manual flywheel, but perhaps, in the effort involved in the V8 installation I'd be better off getting something bigger or I may only regret it. Also, I can't quite bring myself to install something which is more than several years older than the 300Tdi I already have.

Any thoughts/input please?! Thank you

Post #909566 26th Jun 2021 4:46pm
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Romadog



Member Since: 07 Jul 2011
Location: Warwickshire
Posts: 1730

Agree with Shroppy and Greeni.
Tornado will map your GEMS ECU for correct application. Basically ship it to them and pay them some dosh... they will then send it back with their sticker on it, having done the biz to it also, just takes a while before you see the results as you need to finish the build Very Happy

Post #909573 26th Jun 2021 5:42pm
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Rednaxela



Member Since: 23 Sep 2019
Location: UK
Posts: 28

United Kingdom 

4.6 now on its way.

Re. exhausts... Surely I will need catalytic converters? Just that I've seen a fair few who cobble together exhausts without cats.

Post #910993 6th Jul 2021 1:48pm
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Hufflepuff



Member Since: 25 Oct 2014
Location: Hampshire
Posts: 562

England 2005 Defender 90 Td5 XS CSW Tonga Green

Interesting point. I think it was 1992 in the UK where they became mandatory, so your 1998 vehicle would fall into that category.

I circumvented that little spanner in the works as I have a 1989 vehicle. I guess it shouldn't be *too* hard to fit a pair in somehow, but it will be another expense. 2005 Td5 90 XS
1989 V8 110 CSW

Post #910998 6th Jul 2021 3:13pm
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Linds Hanson



Member Since: 16 Jan 2021
Location: Cornwall
Posts: 86

United Kingdom 

I would use 3.9 RRC or D1 front pipes which bolt straight up to a TD5 90 system which sounds good and is free flow. R380 does need a oil cooler due to engine heat soak and Swepco oil. Would recomend staying with 1.4 transfer but having Discovery V8 5th gear fitted. All trans mounts from D1 V8 will bolt straight in but you will need to add some extra metal along bottom of D1 V8 x member because Defender chassis is deeper than D1/RRC. Use 19J turbo diesel 90/110 rad as it is large and has a eng oil cooler built in.

Post #911409 8th Jul 2021 1:56pm
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mikeh501



Member Since: 07 Jan 2013
Location: United Kingdom
Posts: 990

United Kingdom 1994 Defender 90 V8 Petrol SW Alpine White

Ive just finished my build and its pretty much exactly what your planning. happy to talk you through it. ive literally made ALL the mistakes lol.


Click image to enlarge


Click image to enlarge

Post #911496 8th Jul 2021 8:35pm
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Rednaxela



Member Since: 23 Sep 2019
Location: UK
Posts: 28

United Kingdom 

If I could find a defender 50th system, cats/Y-piece... Confused

As has been mentioned anyway, I was thinking I ought to use the silencer/rear section I have as they are Stainless and in good order.


Linds, I will probably send the R380 to Ashcrofts to get rebuilt/strengthened. I wasn't completely sure about the higher 5th - was thinking maybe get a Roamerdrive instead. Currently with the 300Tdi there are many roads I use where 4th is just a bit too low and 5th a bit too high, but of course it would be a bit different with the V8 I presume.

Yep, I've read a bit about the 19J td radiator being a good option, I see AlliSport do a Defender V8/50th radiator, and would save me from having to get and older one re-cored.

Post #911497 8th Jul 2021 8:36pm
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Rednaxela



Member Since: 23 Sep 2019
Location: UK
Posts: 28

United Kingdom 

Mike, I've seen some of your thread and it's amazing, enjoy. HufflePuff's looks like it'll be incredible also. Yes there'll be lots of things to figure out, fortunately there's a lot of info out there now also.

Post #911498 8th Jul 2021 8:38pm
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mikeh501



Member Since: 07 Jan 2013
Location: United Kingdom
Posts: 990

United Kingdom 1994 Defender 90 V8 Petrol SW Alpine White

No probs, and if your based anywhere near staffs your welcome to come and have a look. greeni is this way too. i learnt so much by just looking at how other v8s are put together. its all the little brackets and parts you dont think about. the big bits are contained in this thread so its a good start!

Post #911500 8th Jul 2021 8:45pm
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