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28/36 Dcd Weber Carburettor


Oh-KE
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Hello people, so as the title suggests this thread is dedicated to the 28/36 DCD Weber. The reason I am posting about this carb is because I have recently bought one and the reason I got one is because I have read they are a good option for K motors. I have done a lot of research and the more research I do the happier I am with my purchase and I can't wait to get it up and running. It is easily tuneable and a good size for small motors. Probably the only downside I have come across is the lack of parts available. There are rebuild kits and replacement jets available new but not much else.

 

Some of the reasons to use the 28/36 DCD Weber: Tuneable for a large range of motors due to removable and changeable Venturi/Choke tubes, very simple construction making it easy to pull apart and work on, jets seem to be easy enough to get hold of, mechanical secondaries, no rubber diaphragms that will deteriorate, not very expensive if you wait for the right one.

 

Some links I have found useful:

http://myweb.midco.net/gl1000singlecarburetor/Weber_DCD_Explained.html

http://foxed.ca/rx7manual/manuals/36dcd%20manual.PDF

http://freespace.virgin.net/tommy.sandham/weber.htm

http://www.theminiforum.co.uk/forums/lofiversion/index.php/t172681.html

http://www.rollaclub.com/board/topic/20149-weber-2836-does-any-one-know-about-these-carbs/

http://www.imps4ever.info/tech/carbs.html

http://www.rollaclub.com/board/topic/42619-weber-dcd-venturi-sizing/

 

Thats about all I can think of at the moment. I have ordered some jet drill bits and will be experimenting with jetting using the info in the links. Then once I am reasonably happy I will get proper weber jets. It might be a while before I can make it all happen but I will update this thread as I go.

 

Feel free to add any info or ideas on jetting and tuning, although I have a rough idea, I'm not 100% sure where I should start with jet sizes for a stock 4k with extractors. So input is welcome. I know I should get a cam grind to make the most of it and I will one day but not yet so it's going on the stock motor first.

 

Cheers, :y:

 

Chris

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I do not currently have an oxy sensor & a mixture gauge but I am aware how useful they are for tuning and am currently looking into it. I don't really want to have to fork out lots of money on one and I'm not very good with electronics so I'm a bit unsure about them. I would definitely like to have one though.

 

As far as people who have set them up goes I know for sure there have been quite a few people to use them on K motors. Felix has been one to mention them a fair bit, and seems to know a lot about them and tuning them so I will probably start with something similar to the settings he suggest for a 3k. In the 5th thread I posted above there is some discussion and an NZ guy posted pics of one installed on a 3k.

 

The settings that were suggested for the 3k were

 

Primary/Secondary

 

Venturis 23 / 25

Main Jets 125 / 135

Air Correctors 190 / 180

Idle Jets 50 / 55

 

 

My current settings (which are pretty strange, don't know what it could have been tuned for previously but it must have been fairly small)

 

Venturis 23 / 26

Main Jets 100 / 160

Air Correctors N/A / 180

Idle Jets 50 / 70

 

Happy to already have 23 / 26 Venturis. I think this will be alright for a 4k. Also can't get the 23 out because it's jammed so thats staying for moment. The primary Air Corrector Jet had been redrilled and the number has been removed so I don't know what it is. Main jets will need to be changed and secondary idle jet too.

 

I will probably start with something like these settings and work from there..

 

Venturis 23 / 26

Main Jets 130 / 140

Air Correctors 190 / 180

Idle Jets 50 / 55

 

 

Apart from the stuck Primary Venturi and the worn looking Primary Butterfly (which I will be replacing) this carb looks to be in good condition. It has had some work done on it as some stage not too long ago. It's got brand new looking brass floats which is a bonus as I bought it without really knowing it's condition. Here are some pics..

 

IMG_3001.jpg

 

IMG_3002.jpg

 

IMG_3003.jpg

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my 28/36 with vac secondaires. specs are

 

170 main air correction 190sec

idle 55 pri 60 sec

primary jets 150 sec 130 (i think)

 

recently done 300km to 18L :D thats with some 160kph pulls so yea

 

this is tuned with my o2 sensor/gauge

 

lets us know if you need more info

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Thats some good fuel consumption! I really hope I can achieve close to that. What work has been done to the motor? Is your sensor a narrow band or wide band? Was it easy to tune with the sensor??

 

Cheers

Edited by Oh-KE
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worst fuel eco was 16L/100km on GOR this was with the 1600 tune.

 

best was around 6/7L/100km to winton and back. SUPER LEAN FTW

 

rebuilt 4k. torquey cam. little headwork.

 

wide band FTW $150 bucks for the autometer gauge. $20 for the bung. another $20 for the sensor.

 

Was a little [email protected]$king around to tune. i went to my carby guy like 6 times to get jets. but yea its pretty straight forward

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i think its maybe the other way? been ages since i tinkered with it.

 

still kinda have a problem with my idle/idle jets

 

it had 60/70 idle jets and i couldnt turn down the idle cause it was running that rich. so i leaned the idle screw so much it dropped it from 2000rpm to a lumpy 800rpm and sometime stalling

 

so i changed it to 55/60 and idle would stay 1500. couldnt turn it down. leaned it down to 1000 wont turn down with the idle screw

 

i tried 50/55 but it ran like a PIG. epic lumpy cam idle but it surged when driving shaking the car

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  • 6 years later...

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