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ian series 1



Member Since: 17 Nov 2014
Location: south
Posts: 3127

United Kingdom 2008 Defender 90 Puma 2.4 CSW Bonatti Grey
3.5/3.9
Question...

Has anyone done, or know if you can happily run a 3.9 on carbs (SUs)?

I've been offered a good 3.9 engine with a fried ecu, and injectors,
It's a low mileage engine at 64,000 miles.

I'm wondering if the SUs would cope, or need re jetting?

Cheers 80" 80" 86" 88" 90"

Wanted, Forward Control Anything considered.
Post #669176 5th Dec 2017 5:47pm
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Devon-Rover



Member Since: 22 Jan 2015
Location: South Devon
Posts: 916

United Kingdom 2014 Defender 110 Puma 2.2 USW Aintree Green
Hi Half an answer as I have lost / forgotten the info.

Yes you can but it will need different needles and springs and possibly a bit of time with a dyno and wideband exhaust gas analyser to check the mixture and fine tune the needles to get the best mixture.
Post #669212 5th Dec 2017 7:37pm
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ian series 1



Member Since: 17 Nov 2014
Location: south
Posts: 3127

United Kingdom 2008 Defender 90 Puma 2.4 CSW Bonatti Grey
Thanks for confirming what I had thought Wink

I was thinking maybe a phone call to Burlen?
https://burlen.co.uk/


I'm sure they could shed some light on what would be needed?

Cheers 80" 80" 86" 88" 90"

Wanted, Forward Control Anything considered.
Post #669213 5th Dec 2017 7:47pm
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JeremyJ



Member Since: 16 Nov 2011
Location: Aylesbury
Posts: 1758

United Kingdom 
Yes, will work. My 2b is running a 4.6 on SU’s
Post #669217 5th Dec 2017 8:08pm
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ian series 1



Member Since: 17 Nov 2014
Location: south
Posts: 3127

United Kingdom 2008 Defender 90 Puma 2.4 CSW Bonatti Grey
is that on standard carbs Jeremy?

I suppose I ought to just get it, put the carbs on and run it up,
And see how it runs and sounds? 80" 80" 86" 88" 90"

Wanted, Forward Control Anything considered.
Post #669225 5th Dec 2017 8:34pm
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JeremyJ



Member Since: 16 Nov 2011
Location: Aylesbury
Posts: 1758

United Kingdom 
Yes, but I can’t remember which needles are in them.

What about keeping the efi?
Post #669228 5th Dec 2017 8:44pm
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ian series 1



Member Since: 17 Nov 2014
Location: south
Posts: 3127

United Kingdom 2008 Defender 90 Puma 2.4 CSW Bonatti Grey
I'm a big fan of the twin SUs, there is just something about them?

Not a fan of Strombergs, had nothing but trouble with them on an old 2 door RR,

the engine I've been offered is being ditched because of ECU malfunction,
I thought it would be a fun project to strip and rebuild it on carbs.

(Not like I've enough to do).... Neutral Laughing

Thumbs Up 80" 80" 86" 88" 90"

Wanted, Forward Control Anything considered.
Post #669241 5th Dec 2017 9:05pm
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mikeh501



Member Since: 07 Jan 2013
Location: United Kingdom
Posts: 1142

United Kingdom 
wont it need a different front end with distributor? and a diff intake manifold etc?
Post #669378 6th Dec 2017 7:58pm
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ian series 1



Member Since: 17 Nov 2014
Location: south
Posts: 3127

United Kingdom 2008 Defender 90 Puma 2.4 CSW Bonatti Grey
Yes, there is a fair bit to swap over,
But all doable. 80" 80" 86" 88" 90"

Wanted, Forward Control Anything considered.
Post #669379 6th Dec 2017 8:02pm
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oneten110



Member Since: 02 Jul 2011
Location: Wish I was still in France
Posts: 741

United Kingdom 
Why not just stick with the EFi. Sourcing a replacement ECU shouldn't be a problem and a set of injectors can be repaired in the same way as a set of diesel injectors can.

try having a chat with these people.
http://www.tornadosystems.com
Post #669512 7th Dec 2017 10:38am
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ian series 1



Member Since: 17 Nov 2014
Location: south
Posts: 3127

United Kingdom 2008 Defender 90 Puma 2.4 CSW Bonatti Grey
I want it to keep it simple, it's for a series 3, 80" 80" 86" 88" 90"

Wanted, Forward Control Anything considered.
Post #669514 7th Dec 2017 10:51am
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oneten110



Member Since: 02 Jul 2011
Location: Wish I was still in France
Posts: 741

United Kingdom 
Honestly it is probably simpler to set up than carburetters.
I took my 3.5, that I had fitted with a 3.9 EFI system, to Tornado and they set it up in about an hour, managing to double the power output at the same time
Post #669517 7th Dec 2017 11:12am
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ian series 1



Member Since: 17 Nov 2014
Location: south
Posts: 3127

United Kingdom 2008 Defender 90 Puma 2.4 CSW Bonatti Grey
I did think about going EFI when I started the project,
But as I said, i much prefer them on carbs.

I don't think anything can beat it when they are set up properly Wink 80" 80" 86" 88" 90"

Wanted, Forward Control Anything considered.
Post #669520 7th Dec 2017 11:28am
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muddypaws



Member Since: 22 Jan 2013
Location: Leicestershire
Posts: 122

England 2009 Defender 90 Puma 2.4 SVX Station Wagon Santorini Black
This is your man for advice on SU's

http://www.johnealesroverv8.co.uk/ Richard

Defender 90 SVX
Post #669895 9th Dec 2017 6:14pm
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