Webers for the e type

Agree totally. James, you started a thread previously re: linkage. I sent a pic of my “home made” W/ cut & welded S.S. splined shaft. Thought you were going to Terry’s gorgeous linkage kit. Guess you got yours working to satisfaction(not easy).
Folks seem to miss the importance of a completely stable end to end shaft that
has no bend & opens & closes at exactly the same time across all 3 carbs.
And possession of the “Synchrometer” -carburetor flow meter on James’s front R. tire. A not obvious clue to those who don’t know, Mr. Love?
And don’t even start adjusting these magnificent carbs W/O buying “Weber Carburettors” by John Passini AND How to power tune the Jaguar XK by Des Hammill.
Be patient. You must be if you work on your own E-type. Ex. “It’s running too rich.”
Here’s where the books come in as you’ll need to understand the relationships among the main jet & air correction jet & how the emulsion tube effects both. And the pump jet & idle jet(Carries the first 1/3) before the emulsion tube even takes over.
All in the 2 books. Read& read. And don’t forget those adjustment screws, and a friend who has the ear to turn them perfectly. I swear, you don’t need a dyno. If you’re not going racing.
Correctly adjusted it starts in 1 Revolution. Idles perfectly &pulls to red line evenly. No spits anywhere. Worth the time invested. The bling is icing on the cake.
I also opted for Isky X-M -2 cams. They’r mild, not racing. Just enough.
Michael Caro

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Yeah Mike for sure.
I would say biggest issue I have had with the Webers is with the return springs. I have done all sorts of things. I have noticed that when the carbs are warm, the internal springs become a bit hesitant to resort back to original position. You can hear how evident it is in this video, it seems like I don’t know how to drive a stick, but in actual fact the throttle was sticky. :sob::exploding_head:

Idle is super smooth. I have played around w linkage in every which way to find the right system that works. Can be tough w LHD cars as you know. :smile_cat::heart_eyes_cat::stuck_out_tongue_winking_eye:

Well, this is an entertaining read - I do love this forum.

I’ll just be boring - Garth, I get it, I bought a series 2 that had triple Webers, and I just decided I was going to make them work, and as everyone has mentioned, it took a long time. But it really started with reading some of the articles and books out there on Webers and really understanding how they work, and then of course I spent a ton on jets and emulsion tubes and choke removal kits and all that, and eventually, with the aid of a synchronizer, a Colour Tune and a lot of road tests, I got them running really well. Consider that my goal was to have a driveable car, I was not trying to extract maximum performance, just get really good driveability.

I did completely rebuild the carbs first, DCOE 152s, then put the suggested setup in, and went from there.
Here’s where I started:
Choke 38
Aux Venturi 3.5
Main Jet 155
Air Corrector 190
Emulsion Tube F7
Idle Jet 70F8
Pump Jet 50
Needle Valve 250
This was way rich, fouled the plugs in no time.
I ended up with:
Main Jet 140
Emulsion Tube F2
Idle Jet 55F8
the rest stayed the same.

And I did waste a lot of time by ignoring something that I knew was a problem but somehow convinced myself I should be able to work around. I had one carb that I couldn’t synchronise (I could have started drilling holes in one of the throttle plates, but I had visions of swiss cheese and still no resolution), and I made no real progress until I sorted that out properly.

Oh yeah, I did take the choke mechanisms out and replaced them with the choke delete kit. Having one carburetor was enough, I didn’t need a second one acting as a choke. I don’t drive it in the cold and it starts fine with a couple of pumps.

Now that they work, I love them, but it was a good couple of months where I wanted to sell the car every second day. But I couldn’t. Cause it wouldn’t run.

Good luck, keep us posted.

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James,
I don’t see an external return spring on your linkage. Absolutely necessary IMHO. I’ll try to attach a picture of mine. I put an additional lever on the shaft, pointing up. Drilled a hole in the top for one end of the spring. The other end of the spring is attached to a standard return spring plate. The hole slides over the the threaded pin under the cam acorn nut. Then tighten the nut down. The spring plate has a 90 degree bend, so the small hole is on top & the other end of the spring goes in there. Hope I can load the pic.
Your car is beautiful! Aren’t you afraid of driving the car W/ open trumpets! You’ll suck dust in that can score the cylinder walls?
I like the commenter below also removed the “chokes” - they’re not really chokes. I think they’re called enhancers & are not needed. One pump on the pedal & there’s plenty of gas. Who ever you buy jets, etc. from will have a kit, which I think is just a gasket & a plate.


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Looks like I sent 2 pics.
W/O an external return spring you run the risk that you’ll press the pedal full down & when you lift your foot off, the carbs stick full open!!!
Do this before you drive it again.
Mike

Bruce,
Hit the wrong button & your response deleted.
What is a color (? Forgot the 2nd word) & can’t go back & see it.
I’ll exit forum & go back in. Maybe that will work.
Mike

Phew, got it back!
What is a Colour Tune?
Mike

Terry,
Your engine sounds GREAT!
Mike Caro

Yes Michael for certain! That was picture from last winter. I have since put 3 return springs adjacent each carb. Your right though, it had frightened me a couple times when I drove her without the bonnet. I had throttles jam open before I fiddled too much with the linkage. :cold_sweat:🫣

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Thanks for posting the vid Paul.
Mike, as you can see in the video, it’s a clear sparkplug so you can see the colour of the flame as you adjust the idle mixture (technically, the idle volume on a weber as the idle jet sets the mixture ratio and the idle adjustment meters the amount of mixture). Really useful, a little tedious as you have to do every cylinder at least a couple of time, but along with the synchrometer it takes most of the guess work out of setting them up.

Yes, Thanks Paul & you, too, Bruce. Now I have another thing to buy & try!
And James, remove & block the “chokes”/enhancers. As Bruce noted:
“Another carburetor”. 1 press on pedal gives plenty of gas to start.
Mike

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Thanks Mike. plus 20

I would also recommend reading Des Hamill’s “How To Power Tune Jaguar XK 3.4, 3.8 & 4.2 Litre Engines.” It has a chapter each on both SU and Weber/Dellorto carb types. The Weber/Dellorto section has a table of starting points for 38 and 40mm Webers and Dellortos respectively.

The second paragraph of the Weber & Dellorto chapter:

“You can’t just buy a set of triple sidedraught carburettors and bolt them to an XK engine and expect miracles. Tuning XK Jaguar engines is just not like that. The fact that there always seem to be highly priced, triple sidedraught induction systems on the second-hand market seems to prove the point. These induction systems are usually being sold because they did not work well, and getting rid of them is seen as the old solution to getting some money back. Few people will sell these induction systems because they were fantastic on the engine! Most people just can’t get them tuned properly and give up.”

One other sentence later on seems to mirror the trend seen on this thread:

“However, for every XK engine that goes very well when fitted with these carburettors, there are probably five that don’t…”

On the bright side, the next paragraph says:

“If your engine is equipped with Weber or Dellorto carburettors and lacks performance, don’t despair - whatever’s wrong can be fixed. The jetting can be altered quite easily by merely substituting parts.”

Later on:

“The jetting specifications in this book are realistic, tried, tested, and proven for average high performance applications where mainly standard parts are going to be used and where the revs will not exceed 6000rpm.”

In the SU section Hamill also indicates that triple 2" SU’s were more than sufficient for the XK for road use. In fact, he states that twin 2" , or even 1 3/4" SU’s are sufficient for even modified road-going XK engines.

Dave

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James,
Re: open trumpets.
Decades ago when I first put the webers on I had a strange “flutter” when getting up there in 4th, around 70 - 80 MPH. Super frustrated I went to the Weber Guru here in Ct., Jim Inglese. Known for V-8 Ford, Cobras, Chevy high performance engines using Webers.
Played W/linkage, emulsion tubes, jets. Couldn’t get it out. “I’ve never seen this before” he said - bonnet up & standing on the passenger side. “Dammit. What the hell is that? Where’s that go?” He was looking at the large rectangular opening on the passenger side, inside the bonnet that goes up to the front. It’s an air channel for the huge aluminum canister W/the 2 tubes for stromberg air filter. Opening is 90 degrees to the openings of the trumpets & blows right across the fronts. Thereby disturbing & sucking the air away. Just in case it happens to you.
Michael Caro

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Thanks Michael it’s a series 1 bonnet. I did remove that intake piece too hopefully trumpets are not disturbed. I haven’t really driven the car to 80mph for any sustained amount of time. Not yet anyways. :smiley_cat::cat2:

Thanks for the numbers!

Dave, I’ve read most if all of your posts and do appreciate the comments. However, the “kit” came with the engine and was included in the rebuild price so I’m going to try them and hope for a miracle. I also have Hamill’s book and will refer to it. I’m keeping all of the Stromberg parts, manifold(s), etc as a backup, and in the future can always mortgage my house for a set of triple SU’s.

I seem to remember a Road & Track article from the 60’s / 70’s about triple Weber carbs tested on a stock 4.2 series1 e-type. I think it lowered 0 to 60 times a half second.
I think that the SU’s would not inhibit air flow but the webers offered slightly better fuel metering. Possibly the Weber accelerator jets reacted a little quicker than the lift of the SU dashpots?

Ostensibly, that’s often time is the reason given to use Webers. I’ve driven both on the street, and I never noticed any lack a throttle response on a car with SUs.

By and large, the only thing Webers really do on a street-tuned engine is make pretty noise and look expensive!

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