Twin Weber 45 DCOE question for 2002 e10

[Radio Fixer]

Hello,

I bought twin Weber 45 DCOE with "Cannon intake manifold kit" for my 1975 BMW e10 many years ago. Finally after restoring the car installed them but unfortunately they are not running correctly. Cannot balance the carburetors using Synchrometer tool.

 

Currently I am using E10 engine, with raised high compression pistons, E12 head and camshaft from 1973 Tii. Unfortunately, I do not remember what size of pistons was installed.   

 

Car has no power when driving, max speed 10 to 15 miles only.  Idle below 1200 car shakes badly and turn off. I have research online as well as books for correct Jet sets. Before buying more parts want to check with you to see what you are using on your Twin Weber 45 DCOE.

 

Below chart indicates my finding from this forum on the left (40 and 45 DCOE WEBER JETTING info!), Center section is what Cannon Kit suggest, and the on the right what Haynes Book suggest.

 

Thank you very much.

Regards, Jay

 

 

Edited May 15 by Radio Fixer

[Son of Marty]

Please attach a picture of you set up on the car. Your jetting looks reasonable for a 9.5 to 1 car with a stock cam, what fuel pressure are you running and how are your floats set, but if you can't get them to sync I think is your first point of correction.

[Radio Fixer]

Thank for quick reply. I just added my carb setting to the chart. I need to buy fuel pressure gauge. 

Have a good day.

[uai]

You are way overcarbed. 
Get a set of 40 dcoe and a corresponding Distributor and manifold.

You can try to get this running but it‘s a waste of time and money.

Think of drinking from a bucket unless you have a very large mouth a glass works better.
45 make sense when you're running a ported Engine with large valves and a 300° plus cam.
When you're running a stock Engine/cam  with raised compression 40s are the way to go.
And: you'll need a modded Distributor or at least a ti(i) distributor

Edited May 15 by uai

[Preyupy]

Are you running air filters.? If so make sure the round hole just above the left air horn ( looking at the carburetor) is not covered.  They will idle but as soon as you try to open the throttle it will fall on its face.  

[halboyles]

12 hours ago, Radio Fixer said:

Cannot balance the carburetors using Synchrometer tool.

 

Almost all tuning manuals instruct tuners to first make sure the linkage is working properly before attempting to tune the carbs.  We suggest you use our Ultimate Side Draft Linkage System because it eliminates the linkage as a problem system in tuning.  Check it out at:

Weber Universal Side Draft Linkage System | 2002s Only

WWW.2002SONLY.COM

---

The Universal DCOE System works with any one- or two-piece manifold including OEM, IE, Cannon, Korman, Warnerford, …. This is the best System for most Side Draft conversions including those with the DCOE choke mechanism installed. $265 plus shipping. NOTE:...

Hal

 

[Radio Fixer]

To answer some of the questions:

1. currently using Facet Fuel Pump - Electric In-Line - Solid State, I think it offers "2 to 3.5 PSI". 

2. Using RamFlo air filter for Weber DCOE.

3. Also using mechanical distributors, BMW Tii Bosch Distributor 0231188002-JFD 4.  Tt does not have vacuum system.

Please see attached pictures.

Thanks

Edited May 15 by Radio Fixer

[uai]

You can do the base sync by opening the screws above the transition holes and use a lamp in the trumpets to adjust the butterflys to be about the same.
 

[Radio Fixer]

Thank you for assitant

 

Edited May 15 by Radio Fixer

[Son of Marty]

Pic's of the carbs, please.

[Preyupy]

There are so many possibilities.  You are sure the spark plug wires are correct, ignition timing is correct?  Show us a picture of the way your throttle linkage is hooked up. 

 

There are some basic Weber things you need to look at.  Where are the idle mixture screws set?  Close them all the way but DO NOT TIGHTEN THEM, gently turn them until they stop then open them 1.5-2 full turns out.  This should be a reasonable place to start.  There is also the possibility that the Aux Venturies are not installed correctly, they are held in place with a set screw and if it is not tight they can turn and or someone put them in backwards.  I've seen it more than a few times.  Back the idle speed screws out all the way on both carbs and make sure the throttle plates are closed.  If the linkage does not allow them both to be closed at teh same time you need to adjust the linkage until they do.  This is the starting point for balancing them.  

 

We all started somewhere working on cars and it is hard to advise you with limited information.  How good of a mechanic are you? We might assume that the basics are things that you have already gone over 3-4 times and you have a complicated 1 off problem or we might encourage you to make sure you have the firing order correct with your spark plug wires.  You installed the carbs?  Have you checked for Vacuum leaks?  What kind of gaskets did you use between the carbs and the manifolds?  The isolating type can be easy to mess up and you can have a major vacuum leak. 

 

A few places to start 

[Son of Marty]

On the Cannon manifolds some times the enrichment section on the carbs hit the manifold and prevent a air tight seal, it's a easy fix and worth checking out. Also are you using the anti vibration  isolation mounts or the solid spacers?

[Hans]

In addition to that shopping list, are they Italian or the newer Spanish versions? The latter has different float and initial mixture screw settings.

It would be helpful if you could find the choke size. It will be stamped on the choke.

 

I agree with the comments about 45s on a stock motor. A friend solved his carb problems by swapping his 45s for 40s.

 

Edited May 16 by Hans
More

[mike472]

On 5/15/2024 at 1:16 AM, uai said:

You are way overcarbed. 
Get a set of 40 dcoe and a corresponding Distributor and manifold.

You can try to get this running but it‘s a waste of time and money.

Think of drinking from a bucket unless you have a very large mouth a glass works better.
45 make sense when you're running a ported Engine with large valves and a 300° plus cam.
When you're running a stock Engine/cam  with raised compression 40s are the way to go.
And: you'll need a modded Distributor or at least a ti(i) distributor

I've been there and made this mistake buying 45's instead of 40's.  I'd sell the 45's and buy a set of 40's right now.  You might get them running better then they are now because something is badly wrong with your particular setup because your engine shouldn't be dying at rpm's past 1500, but they will never be fun at low speeds.

18 hours ago, Preyupy said:

There are so many possibilities.  You are sure the spark plug wires are correct, ignition timing is correct?  Show us a picture of the way your throttle linkage is hooked up. 

 

There are some basic Weber things you need to look at.  Where are the idle mixture screws set?  Close them all the way but DO NOT TIGHTEN THEM, gently turn them until they stop then open them 1.5-2 full turns out.  This should be a reasonable place to start.  There is also the possibility that the Aux Venturies are not installed correctly, they are held in place with a set screw and if it is not tight they can turn and or someone put them in backwards.  I've seen it more than a few times.  Back the idle speed screws out all the way on both carbs and make sure the throttle plates are closed.  If the linkage does not allow them both to be closed at teh same time you need to adjust the linkage until they do.  This is the starting point for balancing them.  

 

We all started somewhere working on cars and it is hard to advise you with limited information.  How good of a mechanic are you? We might assume that the basics are things that you have already gone over 3-4 times and you have a complicated 1 off problem or we might encourage you to make sure you have the firing order correct with your spark plug wires.  You installed the carbs?  Have you checked for Vacuum leaks?  What kind of gaskets did you use between the carbs and the manifolds?  The isolating type can be easy to mess up and you can have a major vacuum leak. 

 

A few places to start 

Preyupy is right in that there are quite a few things that could be wrong with your basic engine setup.  Sometimes it takes more then a basic level of expertise to figure it out too.  But many times it winds up being something other then the carbs.  As one of our contributors to the forum likes to say... "All of your carb problems are in the ignition"  It's true more often then you think.

[Schon '02]

On 5/14/2024 at 8:25 PM, Radio Fixer said:

Hello,

I bought twin Weber 45 DCOE with "Cannon intake manifold kit" for my 1975 BMW e10 many years ago. Finally after restoring the car installed them but unfortunately they are not running correctly. Cannot balance the carburetors using Synchrometer tool.

 

Currently I am using E10 engine, with raised high compression pistons, E12 head and camshaft from 1973 Tii. Unfortunately, I do not remember what size of pistons was installed.   

 

Car has no power when driving, max speed 10 to 15 miles only.  Idle below 1200 car shakes badly and turn off. I have research online as well as books for correct Jet sets. Before buying more parts want to check with you to see what you are using on your Twin Weber 45 DCOE.

 

Below chart indicates my finding from this forum on the left (40 and 45 DCOE WEBER JETTING info!), Center section is what Cannon Kit suggest, and the on the right what Haynes Book suggest.

 

Thank you very much.

Regards, Jay

 

 

Here are my settings with 45DCOEs and a Cannon kit:

- Emulsion Tube: F9

- Idle Jet: 55 F9

- Main Jet: 155

- Air Correction Jet: 180

- Choke: 34

- Misc: Schrick 292 cams, Stahl headers, MSD Ignition 

 

The set up is for street use and generally tractable with a slight lumpy but acceptable idle.