Help with a non-starting 3.8

[Treetrimmer]

The saga continues!

Whilst waiting on the delivery of gasket sets etc from Burlen, has anyone any tips on removing the carburettors?

I've photographed and then removed all the ancillary bits around the carbs, apart from the inter-connecting spindles and the four nuts per carb. Is there a trick to getting at the lower nuts? I guess carb. removal is usually done with the engine removed, but I'm in no position to do this.

So, (a) are the interconnecting spindles usually removed with the carbs in situ?

(b) what's the best way to get at the lower nuts on each carburettor ?

I look forward to your suggestions.

Regards, Richard

[cass3958]

You are right the carbs are better removed with the engine out but can be removed with the engine in as I have done several times. What you need is a small boy you can hold by the ankles who has long thin arms and a second elbow halfway up the forearm.

Without the above you have to have the patience of a Saint as the lower bolts are obtainable, but you have to use a stubby 1/2 inch open ended spanner, which you can get on to the two inner bottom nuts from underneath. With your arm coming up from under the carbs whilst lying across the top of the wing, you can only just turn the nut 1/8th of a turn at a time before you have to turn the spanner around to get it back on the flats of the nut. It does not help that you have a spring washer under the nuts so you have to get the nut half off before you can spin it with a couple of fingers. The nuts cannot be accessed from under the car and I would remove the bonnet as it does not lift high enough to allow you to work comfortably. Top tip is to undo the bottom nuts first so there is tension on the carbs against the inlet manifold from the top nuts, which means you do not have to wind the bottom nuts off too far before they will spin with your fingers.

I have always taken the carbs out as a pair as all the brackets holding them together are just as hard to remove as the lower nuts. You can gain a little room by removing the dizzy cap and front water pipes to the rad. I also remove the brake fluid reservoir or at least move it to the side. The Battery can be removed from the bulk head but that is about it.

[Orlando St.R]

You can remove the interconnecting spindle with the carbs in place, but I've always removed one carb first, then the spindle.

There is no special way of removing the lower carb bolts that I'm aware of. Just conventional tools and double-jointedness. You may find a socket on a long extension works for some of them. Mine never seemed that tight. It's a slow process, but I've done it a few times now.

[Treetrimmer]

Hurrah-both carbs are off, and my back still works!

I moved the brake fluid reservoir ( as per Cass/Rob), and as mine is an auto, I removed the auto box dipstick guide bracket .
I slackened the flexible couplings, slide them along slightly, and removed the carb. interconnecting spindle. I then removed the battery and tray, and disconnected and moved the brake servo vacuum pipe from the inlet manifold. I undid the accelerator linkage pivot point, where it bolts into the inlet manifold
I then had quite reasonable access to the sides of the lower nuts of each carburettor.

I was surprised to find a relatively crude connection from the bottom of the A.E.D., a metal pipe "T" piece, with two rubber pipes going to either side of the inlet manifold. This arrangement wasn't visible when the carbs were in place. Would someone please assure me this is a genuine piece of Jaguar plumbing. Burlen, the S.U. people don't have a drawing showing the plumbing. I now have plenty of photos, taken at each stage of the dismantling. I have ordered E10 compatible replacement rubber piping for the A.E.D. connection, and the pipe from the fuel bowl to the carburettor fuel rail.
My strategy now is to dismantled and clean the front carb and the A.E.D., but to not touch the rear carb until the front one is re-assembled, just in case I need to reference it.

Richard, slowly getting there

[Glyn Ruck]

That's genuine. Let me see if I can find a pic.

Here with & without rubber pipes & clips.

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[Treetrimmer]

Ah! Thank you, Glyn, the last of your photos explains a lot.

My setup, as found, is similar but not the same. My "metal T piece" comes vertically straight down from the A.E.D., whereas in your last photo the "T piece" is coming out horizontally. My "interconnecting rubber pipes" are very much longer. I'm not able to get a view of the small metal pipes coming out of the inlet manifold.
I'll attempt to get some photos later today, but meanwhile thank you for your photos, and putting my mind at ease. Looks like more rubber pieces for us Brits to worry about with E10 petrol. My new "E10 proof" rubber pipes are on order from Burlen

Richard

[cass3958]

Mine is a 1967 3.4s and is set up the same as Glyn's photo. The "T" piece going in to the AED has to be undone to remove the carbs as I found you could not get a screw driver underneath to remove the Jubilee clips on the lower rubber pipes. The problem comes when refitting and you are trying to line up the "T" piece thread with the AED. I found the easiest way to connect this "T" piece was to do so before you tightened any of the nuts holding the carbs in place. Sometimes I even connected the "T" piece before even putting the nuts on the studs so you had enough movement to get the thread on the "T" piece started.
A common place for the carbs to leak fuel is at the base of the AED and carb one. There is a joining section between the two with large banjo type bolts made of brass. There are a lot of fibre washes in this area and you have to tighten the bolts enough to stop fuel leaks but not too much to strip the threads between the brass and alloy. The head sizes typical of SU are not standard AF and you need something like a 21mm or equivalent Whitworth spanner to do up the larger bolt. A small amount of thread lock once tight should stop it from working loose in the future.

[Glyn Ruck]

Cass is spot on and absolutely correct about leaks on the fuel supply cross piece from carb 1 to the AED. Mine is the same set up as above but I used two carb sets to achieve one that did not leak at the AED fuel supply cross piece. For the life of me I could not figure out why & did not want to waste time diagnosing. It worked & the carbs were already mounted when we discovered the leak. Fortunately had plenty of spare fibre washers. Battled a little to replace the cross feed with the carbs already mounted. Used some language I would not want others to hear.

Regarding T piece side feed vs vertical feed to the AED. I guess there were variations on the theme over time.

[Treetrimmer]

Many thanks to all those who have contributed to this thread so far. As there seems to be so little written information on the A.E. D. and it's plumbing, I thought it might be useful to try and pull all the known information together. Future "S" type owner/ mechanics may thank us.

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I suspect my A.E.D. Is not original, as the inlet manifold pipe exits vertically downwards, and so is out of line with the metal pipes coming out of the inlet manifold ( see Glyn's photos earlier in the thread.)
I have several queries relating to the bridge piece between the front carb and the A.E.D. On my car, the side "flanges" of the bridge were pointing downwards, in Glyn's photos they are pointing upwards. That is no big deal, but I would like to know which one is correct.
Query 2 relates to the washer arrangement on the banjo bolt connecting the bridge to the base of the front carb

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I'm confident the thicker Ali spacer sits above the bridge, and the thinner one sits beneath the bridge, but where should the single fibre washer be placed? I would have thought there should be a fibre washer between the bridge and both Ali spacers, but there is only one suitable fibre washer provided in the overhaul kit from Burlen.
I have the "S.U. Workshop manual" from Burlen, but there it contains no information relating to the A.E.D. as fitted to our "S" types, and presumably fitted to the Mk 1 & Mk2 and 420.

[John Quilter]

Great photos to show the AED. I just wish SU, or Jaguar, had created a vent line, or lines, from the two holes under the triangular shield to the air filer so that fumes did not escape into the engine bay on hot starts on very warm days creating a gasoline odor .