Thank you for this Frank.
So a European, advance distributor should be connected to the little spigot on the carburetor, as per Peter Balls photo right?
This is how simple my world was before this retard vacuum complication landed on me and I got all confused with lateral explanations… 
As this conversation progresses, an important realization is starting to take shape. This car was originally bone stock US, LHD, Strombergs, full smog paraphernalia. I bought it in London, UK. It run really sweetly, but the carbs leaked. What really amazed me with that car, compared to my previous XJC, was that i could stand behind the car idling and NOT smell ANY fumes at all!!
I came across a 'great deal" for a "new out of a crate, UK specs engine with 2HIFs, and after weighing advice received here, decided for a swap instead of a fix.
The engine seller, a Jaguar mechanic, installed the engine in my car.
That UK engine did not run right, at all, had a nasty noise in the exhaust camshaft (not solved by the stake down kit), hardly went over 70mph, was a huge disappointment. Over the months, I found that the carbs were not balanced, the dash pot springs were mismatched, and… the big revelation was that the carb needles were also mismatched and the wrong type (both). BDY did the trick, and together with a new fuel pump, the car was transformed!! (still not what I hoped for, this is why I recently went for a full rebuild).
BUT, I realize now that this UK specs engine, kept the US retard vacuum distributor with the pipe connected to the spigot on top of the carburetor…
According to what I am reading here now, that uneducated decision was a poor one… Now to be remedied
Thank you all.
I remember Kassel!!! A break point in my armey days as we convoyed from our Home base at Worms to Todendorf. Twice a year to fire our 90MM’s!!
And, later, when i was stationed at Todenfdorf. Just after Xmas in the snow. One hill on the autobahn, my 50 Chevrolet would not climb. Imperative, or be AWOL!!! Ice, no traction !!!
Managed to find a village mechanic in the vicinity. he fitted a set of used chains!!! Saved, got up it. Left them on ll the way there!!
Carl
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Nice Pekka!
You did your speed test with a full tank 17 km after you filled up, it seems! How long did it take to empty the first quarter of the tank, if I may ask;-)?
My own car doesn’t get much exercise either these days. Were you planning to return to Finland in the car?
Stay safe
Jochen
75 XJ6L 4.2 auto (UK spec)
Eric,
in principle, you did everything right: a NOS engine with carbs is as good as it may get and - if it really was NOS - I’m fairly sure it didn’t really need a full rebuild. The thing that makes me suspicious is the fact that it came with carbs. Usually, exchange engines in crates don’t have carbs.
The second very strange thing is the disparate setup of the carb and that your “Jaguar mechanic” didn’t straighten that out. Correct rebuild kits (sold by Burlen) aren’t that expensive.
The rest is pretty clear: mismatched ROW carbs and US distributor won’t go together …
Good you’re on track now!
Jochen
75 XJ6L 4.2 auto (UK spec)
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Pretty sure he switched to the other tank after the first one was empty 17 km in.
Overdrive XJs can be driven very economically, 100l/600km would be in the ballpark for this kind of driving.
I got 13l give, more take at 130 with the automatic!
So his probably 17l/100 to me is quite economical.
When I take the Mercedes to its limits it’s always 10-12l and it is very good at speed.
Nah … the tanks are 2 x 45 litres. At 15 l/100 km you get 600 km out - thats what I get when I’m on long distance trips averaging between 110 - 130 kph.
Granted, the MOD is way more efficient, but at 180 kph the engine is probably doing 4300 RPM and I doubt that it consumes less than 25 litres if kept at that speed. When I floor it I see the water temp guage needle rising just as quick as I see the fuel guage needle falling, admittedly at WOT.
Maybe your a bit spoiled by your fuel injected SIII. It has got quite a few extra ponies and the longer rear axle allows to coast comparatively economically at 140 to 160 I guess.
Best
Jochen
75 XJ6L 4.2 auto (UK spec)
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My best advise is to check vacuum at spigots to be used, Eric - it will show whether the spigot is manifold or ported…
There was no standards for spigot placement on carbs - any carb manufacturer was free to put anything anywhere…
Frank
xj6 85 Sov Europe (UK/NZ)
Hi Jochen,
No, the car now stays there (20 mins from the Frankfurt airport) I have had that garage place now for almost six years, much cheaper than Helsinki and allows us to make trips to Switzerland, Italy & France more quickly.
This way we did Le Mans Classic in 2016 with the 456GT and in 2018 with the 1972 V12 E-type OTS.
Also several times to Villa d’Este, Swiss and German events, Festival of Speed etc.
That was not a “speed test” we had exceeded that many times already after Puttgarden, but we had lunch (in Bad Fallingbostel, outside on a bench, only take away allowed) and filled her up so I asked my wife to take a couple of pics while I was driving again on the A7.
Range was still about the same, 600km, so 300km per tank, I have a habbit of resetting the trip meter every time I fill her up, and switching fuel tanks every 100km so I have a good idea about how much we have left.
Of course it was a bit stressful, not because of the speed, but when it started to get dark and there were only two lanes going our way, passing the lorries is more difficult when there are so many cars wanting to go much faster.
Cheers!
Frank , since its inception, the XK engine carb connection to the distributor vacuum unit advance connection has been / is placed at the position shown, either a push on or, the earlier, male thread method, while the retard connection on the later engines tends to be fitted under a carb , manifold side of the butterfly.
To “muddy the waters” by implying, even with a 
, that the connection can be anywhere !! just adds to Erics slight confusion.
To be of further help perhaps Eric will post a photo of the distributor to be fitted.
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Yes, I will post a photo later.
What does “ported” actually, in the context of not being “manifold”, and how can it’s quality be measured/confirmed?
These vacuum ports are very carefully located near the butterfly. For a vacuum advance system, the port is just outside a closed butterfly at the edge where the butterfly opens by moving toward the air filter. Hence, the port is on the air filter side at idle and hence sees no vacuum, but as the butterfly opens the butterfly passes over the port and the port then sees the manifold vacuum. For a vacuum retard system, the operation is quite the opposite, and hence the port must be near the butterfly on the side where the butterfly opens by moving toward the engine. The port thus sees vacuum when the butterfly is at idle, but as it opens it passes over the port so the port sees atmospheric pressure instead.
There is nothing random or haphazard about the placement of these ports. The location of the drillings are very precise; a millimeter one way or the other would make a considerable difference to the operation of an ignition system. On the V12, there was a recall that replaced the LH throttle body just to provide a couple more vacuum ports to operate the revised fuel tank vent scheme. When connecting stuff up, you must connect each vacuum line to the correct port. Don’t just swap them around willy-nilly and expect the car to run right.
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Wow, now that’s what I call a holiday car to pick up from the airport! Much better than my usual Corsa or Polo:-)
And you’ve participated in the most outstanding classic car events - even though I have to admit I prefer the more down-to-earth fun things like the Lake Constance winter rallye, the Klausenpass Memorial or the Schauinsland or Haldenhof Bergrennen. Some of our club members even went to Italy to join the Mille Miglia, not in registered cars, but in the Mk 2 Spitfires they slept in, and said it was amazing because neither the crowds nor the vigili cared whether they were registered 300 SLRs or not - and still they were greeted with applause when going through villages in Tuscany. But that’s still on my to-do list …
Best
Jochen
75 XJ6L 4.2 auto (UK spec)
Thank you Kirbert.
Here is the photo of the rear carb, showing the spigot for the distributor advance vacuum. Inside, the hole indeed ends exactly ON the butterfly.
You have a car,just for Germany?
I need your job.
**
Brought up on carbs, Peter; I just pointed out the only safe way of verifying vacuum connection is to check vacuum at idle - then there be no confusion…
Frank
xj6 85 Sov Europe (UK/NZ)
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Think of the French word for door Eric,
in this context, when the throttle (butterfly) is closed it blocks the advance drilling. Ie, door closed,
when the throttle is activated the door
( Porte ) is opened.
The retard drilling does not have a door.
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**
A port on the manifold side of the butterfly sees manifold vacuum with the throttle closed, Kirbert - or 0 vacuum (ambient air pressure) if a closed throttle blocks the port or is inside the butterfly
The theory behind all this is that the the faster the air is moving past a point the lower the air pressure - which depends on the amount of air flowing. Which depends on how fast the engine is turning - which depends on the butterfly opening…
Manifold vacuum expresses the engine sucking against the restriction of the throttle position. And manifold vacuum directly affects the cylinder fill - which is a major factor in engine pinking…
And, certainly; the positioning of the ports is absolutely critical - like the port delivering vacuum to the CD pistons. Which varies the needle position for fuel control, and the air speed past the jet creates the vacuum to force fuel from the carbs bowls at ambient air pressure…
Frank
xj6 85 Sov Europe (UK/NZ)
**
Hi,
Nope, we’ll also do Switzerland, Italy and France! 
And possibly Austria, Slovenia, Croatia etc.
And Chichester, UK in September if possible. It’s ca 500+ kms to the Eurotunnel from the garage.
Like I wrote, that garage costs less than 50% of garage space downtown Helsinki and makes participating in car events easier and faster. I had the 456GT there 2015-2017 and again in 2018-2019 and the V12 E-type 2017-2018. Now it’s the coupe’s turn as our plan is to drive to the Goodwood Revival with four adults + luggage. That was the plan for this year but we all know what happened.
Back on topic, Eric’s carb port looks just like mine on the Euro spec 1975 XJ6.
Cheers!
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