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MG MGB Technical - weber dcoe conversion

I am trying to complete a conversion to a 45dcoe152. I have settings as provided by Pierce Manifold Company, but still have problems getting decent idle and good strong performance. The engine is freshly rebuilt, but as far as I can tell is still a stock setup. Had one on an 80 Limited long ago and ran just great. Any input on carb setups that have worked, timing and dwell recommendations (Mallory Dual Point Dist) would be greatly appreciated. Thanks
Rick Sullivan

Rick, I don't have DCOE experience but the following lists basic settings and may help.
http://www.mgbexperience.com/reference/45dcoe.html
Clifton
Clifton Gordon

It would help a lot for anyone to lend advice if if you listed the idle jets, main jets, 2nd venturi size, choke size, etc.
Daniel Wong

DCOE's are not very good for a stock B engine it is just to much carb for it
John Bucannon

A DCOE is not to much for a standard MGB, it is the setup that can be to much. My setup are choke 34mm, emulsion F9, air 160, main jet 165, idle 60/F8 main venturi 3,5. You can have a choke of 36mm. I also have vacuum advance on my weber by pulling a plastic tube from the distributor via the air filter and end it up in front of the throttle about 5-10mm. I have a Lucas 25D4 standard distributor that will need the vacuum from the carb and not from the manifold. My MGB is a -69. The DCOE setup is made by a Alfa expert on a rolling road. Alfas has Webers as standard so lock for a Alfa tunig expert for setting up the Weber. The benefit with webers are that you never need to re tune them.
Tjellvar

DCOE are often set too rich

One problem is each alteration tends to have some effect on the other jet settings

Try the following

36 choke

F2 EMULSION TUBE

main 165

air 155

pump 50

idle 50 F8 ( I think 60 are nearly always too rich)

If it is still too rich on main, you can try going down to 155 main or going up to 175 air

the point to note is that if you weaken by 1 on the main, i.e going to a smaller number, this has approx the same effect as weakening by 3 on the air i.e. going to a larger number

The fuel and air jets are always interrelated


Other emulsion tubes that have worked for me on B are F9 or F16, but I do find that F" works and provides good progression


The next point to note is the distributor advance: this always causes problems because there is no provision on DCOE for take off very close to the throttle itself

You can try mimicking the SU take off by drilling in such a way theta the throttle uncovers the hole but it is risky and requires great accuracy and I do not recommend it

The other way is to obtain a vacuum capsule suitable for manifold take off - see many of the threads on this

CHRIS

This thread was discussed between 03/05/2002 and 04/05/2002

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