Weber 45 DCOE jetting for Renault wedge head (Hermes)

[Nockenwelle]

I bought a manifold and Weber 45 DCOE carburettor from Dan via this site for my S1. Now I need to know the right jetting of the Weber.
The Golden Gate Lotus Club's reference guide states the following values:

Hermes manifold - Weber 45DCOE-13 #19600.022; jetting 1.50 Main; 1.80 Air; 0.45F9 Idle; 0.40 Pump; 2.25 Needle; 34mm Choke; 3.5 Secondary; F2 Emmulsion; 0.50 Orfice

Can anybody confirm these values as they are completely different from the settings I've found in the carburettor.

Thanks, Klaus

[jbcollier]

What was in the carb?

[Nockenwelle]

I found the following jets on the Weber 45 DCOE 13 carburettor:

Main: 155 fuel, 165 air, F7 emulsion
Idle: 70 F2
Venturi/choke: 36 mm
Needle valve: 175
Pump jet intake: 50
Pump jet: 40

The condition of the manifold is like new but the carburettor is well used. I think it has never been fitted to the manifold and is most probably taken from another car.

[RobynS]

Assuming you're running a street driven 1600 the chokes are too big. I'd suggest 32/33 choke with a start point of 135 main. Air jet depends on high speed fueling. Slow running jet will depend on pick up from tick over. Only way to fine tune it is on a rolling road with AFR/Lambda facility.

[Nockenwelle]

I'm not sure if everybody is familiar with the Hermes-style setup. It is a single twin choke carburettor that is shared by four cylinders. The capacity of engine is 1470 ccm. Fine tuning on a rolling road will be the best for sure. Right now I'm looking for a good starting point.

[jbcollier]

I’m not at home right now but this has come up before and I posted the recommendations from the Haynes weber manual.  Do a search for weber + 45DCOE + Hermes or Else and you should find it. Otherwise I’ll post them again when I get home on the first.

[Nero]

From my own experience I would say that it would be the best to get an wideband oxygen sensor. We have done this with my fathers Europa, because there were absolutely no date for the engine. I would not just by parts for the sake of it. With the oxygen sensor you will have some values and go from there. The car will probably run quite rich and the driveability won't be the best due to the venturis. Driving the car a few meters will give you some data to start from.

Greetings from Germany
Denis

[Nockenwelle]

With some luck I found a full PDF copy of the Haynes Weber manual somewhere in the net :-) And the Europa is listed in there indeed:
The values are the same like the Golden Gate Lotus Club ones so I'm going to use them to start with.

Hi Denis, nice first post, willkommen im Forum!
Using a wideband lambda probe will help a lot for sure. As the car is currently not running I'm looking for a good starting point for now.

Klaus
 

[BDA]

  Nero!

And Merry Christmas!

[jbcollier]

+1 on fitting a wide-band O2 sensor.  It makes dialing in the jetting a breeze compared to the not-so-good old days.

[TonyWa28]

Bought an S2 that I'm going through now.  Came with the Hermes setup.  Engine was frozen (water in cylinders for some period of time....), so I have no live experience with the jetting, but I will confirm what was in the carb as purchased.  I'll have a look on the Tuesday when I'm back at the shop.  Will post then.

Tonywa

69 Elan S4SE
69 Europa S2
60 Bugeye Sprite

[BDA]

  TonyWa28! You have a stable there!

[Nockenwelle]

... but I will confirm what was in the carb as purchased.  I'll have a look on the Tuesday when I'm back at the shop.  Will post then.

  I've ordered the standard jets already but I am very interested in the setup in your car. Looking forward to your report.

[jbcollier]

Get a small selection of jets either side of the recommendation you’re following:

Mains and air correctors: +- 0.1

Idle: +- 0.05

Assuming the emulsion tube and venturiis are correct.  That should do it.  Original Italian carbs generally like their idle screws in the 1.5 to 2.5 turns-out range.  Spanish clones more in the 3.5 to 5.5 range.

3K to 5K WOT, tweak the main.  Once that is good then use the air corrector to tweak WOT at higher rpm.

Do NOT go too lean 14.x:1 is a theoretical ideal.  Too lean for engines designed on the 60s.

[TonyWa28]

The jetting that came out of my Hermes setup:

Main 145
Emulsion Tube F8
Air Correction 170
Idle Jet 50 F8
Pump 45
Forgot to check chokes, but will do

@BDA = sad to say that I've thinned the herd down to this group.  Formerly owned a couple of T/C Europas, an Elise, various MGs,, 911, Cayman and a Datsun 2000 (should have kept that one).   The Elan and Bugeye have been with me for many, many years.....  Its been, and still is, a great hobby!!  I suspect with a screen name of BDA that you have a "colorful history" with cars as well.  Glad to be a new member!