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weber 40 doce carb conversion ?

Posted by hawkeye 
brad boner
malaga, washington, USA   usa

I have a weber 40doce that I ( think ) I want to put on my 1979 mg midget . I don't have a intake manifold yet and I am looking for one now . or will try to build my one. has any one got any advise that might help me with this conversion ? I have a header already . will I gain performance ?
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Erick Zanner
Columbus, Ohio, USA   usa

Pierce Manifolds would be my suggestion. Great people to deal with - super tech help (rare these days).
www.piercemanifolds.com
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Sam Cadigan
Olney, Buckinghamshire, United Kingdom   gbr
1975 MG Midget 1500 "Bugger"

Honestly, unless your engine is a serious performance engine, that really needs a great deal of fuel to keep it ticking, I would not suggest a weber.

I have a kit car with a full race trim 1.6 Lotus Twin Cam in it, that warrants the twin webers as it really benefits from slight over fueling and gives that boost on performance, as the engine was built with it in mind.

I assume, and correct me if I am wrong, you have a standard 1500. If so, go for a twin SU carb kit, that's what mine has, it's a very original and period tuning item, and plus, it works beautifully with the car!

Hope this helps somewhat.

Sam.
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Bob Rank
Waldorf, MD, USA   usa
1972 MG Midget MkIII "Silver Ghost"
1994 Chevrolet Silverado 2500 "Blue Beast"
1995 Chevrolet Corvette "Babs Toy"

Brad PM sent.
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Frank Bernett
Niwot, CO, USA   usa

I had 45 DCOE carbs on my 1275 Midget. They were really too large for that engine at altitude, but I put in the smallest venturis and got them to work. The best part of having the webers was I never had to tune them again once I got them dialed in. But be warned, they aren't easy to set them up right. There are many different emulsion tubes and jets and venturis to get right. I would recommend getting some sort of exhaust gas analyzer to help set them up correctly. As for more power they might give you more at the top end. I really did like the way SU's operate, but I couldn't get the needle profile I needed. I'd always be trading off a correct mixture at idle for having it correct at some other load range. I do think the SU's give you a better all around driving car for daily use, but it was nice not playing around with the SU's. I swear I used the same tune on the webers for over 20 years.



Frank
Midget owner since 1975, now owner of an electric '77 midget

www.electricmgmidget.com
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Ron Craven
Clovis, Calif, USA   usa

You already have the Weber use it. I have had nothing but good luck with the ones I've used. Set up right they work great, no having to keep adjusting an SU.
I'm also going to run Miata 15 inch wheels.



Edited 1 time(s). Last edit at 02/04/2014 10:16PM by ronlcraven.
John R
New Fairfield, Ct, USA   usa

Albeit, I am talking a 1275 engine, one carb used. I mounted mine, with the help of Inglese Induction, sage advice and jets, parts, etc. and have never had to do anything to it, it started (on a new rebuild) and just ran perfectly. Only adjustment I ever made was the idle. I did have to bore out the venturi, this was a DCOE40mm.

http://www.jiminglese.com/
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Jeff Schlemmer
Minnesota, USA   usa
1950 Willys Jeep Pickup "Ratrod"
1955 Chevrolet Thriftmaster
1958 MG magnette
1971 MG MGB "POS"
1973 MG Midget MkII   → more

Not a good idea on a stock LC engine. If your cylinder pressures are 175 and higher, you'll be able to get enough velocity through the carb to pull fuel from the jets correctly. Low velocity through the carb will mean less consistent fuel metering and poor drivability conditions such as running on 2 cylinders at idle, and a hard stumble. Then you need to get the ignition set up to advance timing at the correct rate for the new carb. You'd now have the ability to pack the cylinders with a more dense A/F mixture which means you'll need more time fo rthe spark to cut through the fuel at ALL rpms, and its not just as simple advancing the timing across the board - that would cause pinging at 2500-3000 rpms bad enough to cause serious damage.

If you're ready for some hard-core diagnostics and tuning, the DCOE is a solid challenge for anyone!



jeff@advanceddistributors.com
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