Choke problems, Carb replacement

[paulgulliver123870]

Can I pick your collective brains!
The (Banana) 1977 Daimler 4.2 Sovereign coupe is proving a nightmare until warmed up, which is an extended 20 to 30 mins, It is in the garage now, the chief mechanic, who has 40 plus years Jaguar expertise mentioned these are a real problem ! this has had the AED removed and an SU manual choke fitted, he mentioned the only real way around this would be to replace the carbs with manual choke type, I am guessing earlier series 2 or series 1, Does anyone have similar problems, resolutions and perhaps let me know which carbs to look for, Do I need the manifold as well?
Any help as always would be much appreciated.
Cheers
Paul

[mike020150]

Hi Paul,
The AED units are a pain. They don't seem to work well for long even when renewed. However, most owners seem to cope OK once a manual choke kit has been installed. Could you describe the problems you are experiencing in more detail. That might provoke a few helpful suggestions. Mike.

[paulgulliver123870]

Hi Mike
Thanks for your reply, This is a continuation from my last post (Warm up time) I think the earlier cars had Stromberg's, but I am not sure which type these 1977 SU's are, Aparently they were not very good, We always raved about SU ! it was commonly known to be the best carbs about !
I hear about the HD8 HD6 HS6 !!
Need to know, if we go for a complete change out, which ones to get! which had manual chokes built in. I am guessing early S2 or S1 perhaps, but these may have been Stromberg's
Cheers Paul

[Dave Eynon]

Hi
I have been in exactly the same position as yourself with my S1 4.2 originally fitted with HS8 and AED as it is an aircon equipped model. As I have owned the car for 34 years now, in the past I have bought new AEDs, fitted manual conversions to them, replaced diaphragms and coaxed them along for years. Finally, I looked for a long-term solution and found that SC Parts market a conversion kit to enable the AED unit to be removed and the carbs to operate with a normal SU choke arrangement. Easy to fit and set up it has totally transformed the car as the carburation is now accurate at all times and the engine is livelier, more economical and a pleasure to drive. It does take more cranking when cold until the petrol wets the manifold etc but the cold start tickover and warm up is now totally controllable with no hesitancy at junctions etc. The engine bay is less cluttered and not visually correct if originality is important to you.
I see you have later carbs fitted but I would definitely find a way to fit a conventional choke arrangement and remove the AED if you can.
Dave

[paulgulliver123870]

Thanks Dave, sounds right up my street, I have inherited the SU manual choke conversion, previous owner got rid of the AED in 2001.
I have just Googled SE Parts with no luck, could you help with some more details to find the part you mentioned, I wonder if they will fit these carbs on mine. It was all down to the American emissions control in the 70;s.
Cheers
Paul

[Dave Eynon]

Hi, the images you attached still show the AED unit in place although with the manual conversion. The company is SC Parts (not SE Parts) which is a large parts supplier with dedicated catalogues for various models of Jaguar. I tend to try them when SNG and others cannot help me.
The part no on my invoice is 315467. The conversion kit is manufactured by Limora, a German based company, who provided comprehensive instructions in English. I have just checked SC Parts on line catalogue and the kit is still available but if you want to convert the later HIF7 carbs fitted to the S2 it may be best to ring them on 01278 457372 to see if they have a conversion kit for those carbs. Also worthwhile checking if SU themselves can supply the brackets and linkages to fit HIF7s?

[PaulGover]

The long warm up still sounds to me like an issue with thermostats. For a start, a missing or failed cooling system stat would cause the symptoms described, particularly the 20 minutes before the engine gets hot - it should be more like 5; if it were me, I'd whip it out and check it in a saucepan of hot water. However, it struck me that the original AED setup had another thermostat, and even with conversions it might still be about:

The original inlet air box and filter housing contained, AFAIR, a vacuum-operated switch to get hot air from the top of the exhaust manifold through a large flexible pipe. There's also an easily-overlooked pipe round the back of the engine that goes to an old-fashioned wire gauze air cleaner on a plate bolted to the back of the exhaust manifold. I don't recall what happened at the inlet side, but the intent of these two pipes was to provide warm air to the AED and engine during cold starts. I guess depending on what's been re-plumbed since, various things could go wrong that might affect running before the engine is hot.

[paulgulliver123870]

Dave ! I think I found them, Is it SC Parts Group Esher Surrey ??
These are a real find ! lots of bits SNG Barrett dont carry, iv'e got a shopping basket filled already,
I have just had an hour conversation with Mark there, My god he has an enormous wealth of knowledge !! he has put together a package to replace HIF7's with HIF44's that will put it to manual choke, Approx £1300. not bad and a bit of a no brainer! I think we need to get this info out to the rest of the AED community, If anyone wants a set of SU HIF7's with choke conversion please let me know !!
Thanks
Paul

[Dave Eynon]

Hi,
Glad it's been so helpful. I'll leave it to you to write something for the magazine because I agree this issue with the AED needs addressing and making common knowledge. I'll stick to writing up the X-type section for now - until everyone is bored with me anyway!
Good luck with the project!
Dave