aed removal for manual choke conversion

[mustang1]

Hi everyone i am new to the site so be gentle ! i have a very nice 1973 series 1 xj6 4.2 auto with the usual slight misfire carb aed related issues ! i want to get rid of the aed completely and go with a manual choke which some people on line are saying are available ? and also that you could go down the changing for the rover hs8 twin su carb which allready incorporates a manual choke ? has anyone acheived this ? would really appreciate some help ?

mark

[mike020150]

The original AEDs were a pain. The idea was good but in reality they were always unreliable. Since Burlen Services took over SU parts supplies, it is said the company has revised the AED and the units now supplied are reliable. Hence, you might want to reconsider the easiest option of simply replacing the AED. Mike.

[mustang1]

Hi Mike
still a possible plan but the rover p6 200tc had the same carbs HS8 and are an exact same fit but with the benefit of allready having a manual ckoke incorporated and you can still use orginal air filter the look will be the same but no aed ! this has been done many times according to my garage who the owner is a jag man !

[Tintin]

I have looked before but been unable to source the Rover carbs. Instead you can fit a linkage to join the jets of the original XJ set up and use a choke cable to pull these down for cold enrichment (parts available from BFS). AFAIK there are no standard parts to make up a linkage to open the butterflies for additional air at idle (according to BFS the Rover HS8 fast idle linkages are NLA). You may however be able to design and make up such a linkage yourself.

In the end I played about with the AED cam conversion until it worked well enough for me and I abandoned the Rover conversion idea. My set up now cold starts and idles without any throttle until warm enough to shut off enrichment. Some have fitted a solenoid fuel cut-off valve in the supply as a kind of hybrid system but I couldn't vouch for it.

Good luck in sourcing the Rover set up - if you find a second one let me know!!

Robbie

[Mgcjag]

Hi....contact Burlan..they have the parts to convert your current HD8s to manual choke....you need new choke/throttle bodys for the carbs..this will give a proper choke that will pull the jets down to enrich the mixture...cost will be around £350 i think....i havent done it but contacted Burlan a few months ago to discuss it with them....Steve

[RichardSEL]

The original AEDs were a pain. The idea was good but in reality they were always unreliable. Since Burlen Services took over SU parts supplies, it is said the company has revised the AED and the units now supplied are reliable. Hence, you might want to reconsider the easiest option of simply replacing the AED. Mike.

Unfortunately AUH 300 is "temporarily out of stock". But there's lots of other AED bits on Burlen's SU page:
http://sucarb.co.uk/catalogsearch/result/?q=aed

Burlen may do a refurb on your existing unit though, haven't asked yet as even since my '72MY been in the new shop still noone's been to fit the new fuel pump so don't know whether my AED's dodgy (bought car with gravity feed to the carbs -- engine running was as quiet as a sewing machine)

[RichardSEL]

Thought I'd try and eliminate the AED as the source of my "fire then die" situation with my '72MY series 1 4.2L.
Posted a wanted in the buy & sell forum here. Then got offered a replacement s/hand AED unit at a good price. If the symptoms don't change then will assume that either both mine and the replacment AED are showing the same fault, or there's something up with the carbs / carb settings.

Here's the search notes I've just taken. This AED unit is known to be troublesome and was also used by Rover for its P5-P6 V8 and 2000TC. And on the DS420 -- there's probably others. Hope the below helps someone doing a search...

Many years ago I fitted an inline solenoid to switch off the fuel supply to my AED on my '71MY Rover P6 V8 -- fuel consumption increased to 28mpg long run, and 22-24 urban (rebuilt engine with new top end and rings) But found that if I switched off the solenoid too early engine would run but not idle. Then it was difficult to start until the AED's float bowl refilled. Had a Sun specialist tuner re-do the carbs set-up and all was fine until I sold.
That car's still around MOT'd but now green under FLT858J BTW.

The reason is that the AED controls not only a fuel flow but also a quantity of air intake too (didn't know that then) Stall outs in south circular traffic don't cause much popularity in the rush hour

Using Rover 2000TC Carbs on XJ6 4.2L (this info from JagLovers)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Rover 2000TC carbs are absolutely identical to those fitted to S1 4.2 and 2.8 XJ6, with the exception of the manual choke linkage.
"Those carbs are identical to the one I converted last year and they are a steal at 50 quid. The only difference when these are fitted to a Rover is that the float chamber is on the same side of the carb body. This makes no difference whatever to the performance of the carbs.
"The jets are identical to those in the Jaguar, but you have to use the needles from your old carbs to get the jetting correct. They are a straight fit onto the existing manifold and all you have to rig up is return springs and choke cables. There is a separate cable for each carb and they join together with a small junction box in the Rover. I usually contact Wadhams and buy a new Rover 2000 twin cable to make a job of it. Failing that you can use the twin cable setup on the S1 XJ12 if you can get your hands on one. Your original air cleaner also goes back on perfectly.
"All you have to do after that is blank off the air intake on top of the manifold for the AED unit.
After you do this conversion and drive the car you wonder why the hell Jaguar bothered with the AED setup, believe me."

Conversion Kit SNG Barratt
~~~~~~~~~~~~~~~~~~~~~~~~
SNG Barratt is £120 inc for the conversion kit
https://www.sngbarratt.com/uk/#!/Englis ... e7aa9535c8

DMG has their number GAC1030 at £126 inc

Used Elsewhere
~~~~~~~~~~~~~~
The Jaguar part # AUH300<suffix letter>. Moss Europe, Manners/JagSpares (GAC1030), and SNG Barratt lists TZX1002<suffix letter> for "XJ6 1968/87". Jaguar Parts lists that number for "Daimler Limosine". AZX9350 adds DS420. These numbers are also used in lists that stock the manual conversion kit.

[mike020150]

Pics are always good! Mike.

[mike020150]

Nice workmanship! Mike.

[alec2824]

I like the comment that implies that the choke is only needed for 30 secs! Is this really true? Alec G.

[340jag]

It's true , I have HS8's on my MK2 , start with choke , then the engine run's with no choke seconds after !