17 replies to this topic

[lawnmowercrap]

Hey just after quizzing people with a bit more knowledge on webers than myself in relation to jetting. I've recently aquired a 40 DCOE and a Stage 5 head. The person I got them from said that he ran that same weber on that same stage 5 head on a standard 1275 block/cam and then bored to a 1330 and it still ran hapily on the same setup.
I've stripped it to see what jets are fitted and here's what i've got : -

Idle Jets : - 65F8
Choke : - 40
Main Jet : - 195
Air Corrector : - 175
Emulsion Tube : - F2
Pump Jet : - 60
Auxiliary Venturi : - 4.5

Vizzards states the following for a standard 1275, but modified head : -

Idle Jets : - 50F2
Choke : - 35
Main Jet : - 145
Air Corrector : - 180
Emulsion Tube : - F16
Pump Jet : - 45
Auxiliary Venturi : - Not listed but other 1275 examples have a 4.5

I'll be dropping it onto a standard 1275, with the stage 5 head and 1.5 roller rockers. Shall I just drop the carb on and see how it runs / reacts with the above settings? Or will it simply not run?

Lee

Edited by lawnmowercrap, 26 May 2011 - 07:14 PM.

[Ivor Badger]

Is it a 40 or 45, because the biggest std chokes for a 40 are 34?

[lawnmowercrap]

Is it a 40 or 45, because the biggest std chokes for a 40 are 34?

Its a 40 DCOE and the chokes are definetley 40

Edited by lawnmowercrap, 26 May 2011 - 07:14 PM.

[Ivor Badger]

Is it a 40 or 45, because the biggest std chokes for a 40 are 34?

Its a 40 DCOE and the chokes are definetley 40

Sounds like a 45 with a 40 top. What diameter are the butterflys?

[lawnmowercrap]

I think the butterflies are 78mm? (What it says on them)

Lee

Edited by lawnmowercrap, 26 May 2011 - 08:38 PM.

[bmcecosse]

It must be a 45DCOE with 40 chokes ! Which is just as well - since a 40DCOE would be too small for a 1275 engine anyway. Best you can do is run it - and check the colour of the plugs.....

Edited by bmcecosse, 26 May 2011 - 08:07 PM.

[lawnmowercrap]

It must be a 45DCOE with 40 chokes ! Which is just as well - since a 40DCOE would be too small for a 1275 engine anyway. Best you can do is run it - and check the colour of the plugs.....

Is there any definete way of identifying whether its a 45 or a 40?

Lee

[bmcecosse]

Yes - the fact it has 40mm chokes is the clue...... But - just to clarify - how do you know these are 40mm chokes - where are you measuring that 40 mm ??And the butterflies CANNOT be 78 mm!!

[lawnmowercrap]

Yes - the fact it has 40mm chokes is the clue...... But - just to clarify - how do you know these are 40mm chokes - where are you measuring that 40 mm ??And the butterflies CANNOT be 78 mm!!

I am simply quoting the numbers / idents that are on the jets / chokes / butterflies etc. The chokes have a big fat 40 embossed on them, and the butterflies have a big fat 78 stamped on them.

Lee

[Ivor Badger]

Yes - the fact it has 40mm chokes is the clue...... But - just to clarify - how do you know these are 40mm chokes - where are you measuring that 40 mm ??And the butterflies CANNOT be 78 mm!!

I am simply quoting the numbers / idents that are on the jets / chokes / butterflies etc. The chokes have a big fat 40 embossed on them, and the butterflies have a big fat 78 stamped on them.

Lee

try 78 degrees. What width is the hole they fit in? You can't fit 40 chokes in a DCOE40 as they wouldn't exist by the time they were machined out to go in the body.

[lawnmowercrap]

The holes measure at around 45-46mm roughly

Lee

[Kerrin]

A photo of bottom of the carb body will help, are there grub screws and lock nuts on the outside of the choke casting or a plain body, Grub screws = 45. Plain =40

To me the jetting looks far enough out to make it run rubbish, the mains are quite large compared to the vizard recommendations and will run rich. the rest are not too far out but enough. Butterfly IDs are the type not the diameter, some have slots or grooves to prevent flat spots, just measure the hole diameter.

You can drill out or solder up and re drill the main jets and air correctors to fine tune them, but the emulsion tubes and idle jets are more complicated, the F16 emulsion tube are quite common as they seem to be a fairly common fit for Ford engines too, in twin carb form.

Having run a mini on a 45 Webber, a few (ok many) years ago when I was a teenager, it was rubbish, Jetted properly it probably would have been great, but the backfires and flames lit up the countryside. Air leaks on the rubber o ring gaskets were the main cause.

Like anything else if it is set up properly and not worn out, it will be fine. Lean idle jets or mains, and the wrong pump jet causes horrible spit backs and flat spots.

Try it and see, but I think it will need fettling, I will check my spare jet tin to see if I have anything near what you are after, both our Escorts are on Injection now.

[lawnmowercrap]

The chokes have a number on them, have a look down the hole (as you put it) and you can see the embossed number on the edge of the choke. The choke is a separate part that fits in the hole

Yeh thats the number im quoting, 40.....

[Kerrin]

Is that your carb photo on the other thread?

if so it is a 40, the trumpets are sleeved into the chokes, on a 45 the trumpets bolt on the outside.

[lawnmowercrap]

Hi Kerrin, apologies didnt see your previous post. No thats not my carb, just one I found on the internet.
It has grub screws and the trumpets bolt onto the body of the carb, so this would make it a 45 then? Thanks for the easy way to differentiate between the two.

Lee