Hi, Iv finally given up on my 3.9 injection system that was fitted to my 3.5 V8 Defender. When it goes wrong you can’t find anyone to work on it and the guys who know what they are doing cost a fortune, Parts cost a fortune even 2nd hand...!!! The internet is full of forums complaining about poor running issues with the early injection system so why are we converting from good old carbs to something that is over 25years old and has been pulled out of an old scraper....? Who out there is running carbs and can give us a little advice on what set up would work best...?

Webber 4 barrel carbs work quite well on the RV8 plenty of tunability

You could also reinstate the Strombergs.

Henry_b said:

You could also reinstate the Strombergs.

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SU's were fitted from '86 & the quoted power was 134, up from 114 with the Strombergs, but whether the increase was purely down to the carb re-spec. or other changes as well I'm not sure. We all know the Stage One V8 had restrictor plates under the carbs, but I also believe (having seen 'photos) that the early 110 V8's had some sort of restriction as well.

Would that be a Weber 500 carburettor

Single carb or SU’s, Which is easier to set up and which is more reliable....

The standard twin carbs need balancing & linkages correctly adjusted & there's two of everything to go wrong.
You'll need to fit the appropriate inlet manifold.
You also need to consider what air cleaners you are going to use.
Usually a few complete manifold/carb setups on ebay both standard & Holley/Weber/Edelbrock but on used stuff you've no idea if the carbs are OK.
Worth a read:
http://www.wolfitt.com/carbs_and_manifolds.htm

partsrange (AKA RPI) don't appear to like the Holleys. http://www.v8engines.com/carbs-1.htm

Rimmers list 4 barrel conversion kits. All around £1000+.

What gearbox have you fitted as you'll probably need to sort out the kickdown cable if an auto (esp if a ZF4HP22 which shouldn't be run with the kickdown cable disconnected)

Awkward said:

Hi, Iv finally given up on my 3.9 injection system that was fitted to my 3.5 V8 Defender. When it goes wrong you can’t find anyone to work on it and the guys who know what they are doing cost a fortune, Parts cost a fortune even 2nd hand...!!! The internet is full of forums complaining about poor running issues with the early injection system so why are we converting from good old carbs to something that is over 25years old and has been pulled out of an old scraper....? Who out there is running carbs and can give us a little advice on what set up would work best...?

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The 14CUX hotwire injection system is quite basic and easy to set up and maintain. Some parts are difficult to source and are expensive, for example, throttle potentiometer. I would respectfully suggest you stop and cool off. Invest some time searching this forum there is so much information about things to check and how to set up certain parts.You haven't actually said what is the cause of your frustration but I suspect some time with a wiring diagram and a multi-meter and you could sort it out.

Although you are blaming the EFI you need to consider your ignition system as well.

The EFI setup gives better power and "economy" and if looked after will tolerate no end of abuse. I know the pain of hotwire injection. When I first took on my RRC it took me 2 years to get it running right, so many times I nearly gave up. I am so glad I didn't. So really, stick with it, suck it up and keep going.