Weber DCOE tuning , Part 1 - Idle and Progression -
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- เผยแพร่เมื่อ 7 พ.ย. 2022
- In this video we tune the weber DCOE carb, and more specific the idle and progression phase. In part 2 we will address the acceleration and main venturi. For more details on the weber DCOE, how it operates, how to rebuild and baseline it, please refer to the following videos:
• Part 1, understanding ...
• Weber DCOE Part 2 A, d...
• Weber DCOE, Part 2B S...
• Weber DCOE, Part 2C Sp... - ยานยนต์และพาหนะ
This is like having an uncle who's an accomplished racer, mechanic and friend. Learning volumes from this series. Besides, your shop is fascinating and fun to look at.
I love your videos, so carefully shot and edited with simple clear explanations. It really feels like attending a university lecture. These have helped me immensely and I appreciate your efforts.
Straight to the point, put to practice, super easy to understand, best tutorial I’ve seen so far 👏🏻
‘Progression holes’...always wondered what they were for...learned something new again. Thank you sir.
Thank you for the comments.
Thank you for an excellent tutorial! You won’t believe how I’ve been looking for something like this😊.
thank you
Where is part 2 tunning acceleration and main stream?
uff finally. I have been waiting for this one for quite some time. Looking forward for part 2 :) thank you!
My pleasure
I have an 83 corolla with a carbed 4ag. All of your videos have helped me so much with this. Awesome to see you revisiting the subject!!!
Thank you, well some people asked for the actual tuning....
Me too! I was a bit hesitant to start pulling the carbs apart until I watched this series. Glad I did though as they had a load of grit inside them, my idle is nice and smooth now (for 288deg cams anyway)
@@D3Sshooter I think an awesome video that hasn’t been done yet on the YT is a Dyno video showing what the jetting will do/change. However it is quite expensive to rent a rolling road and do pulls consistently. Love you videos, keep up the work!
Excellent video. Explanation that I understand having battled to get my DCOE 40s right on my Alfas. Thank you for your time and effort. Great help. Will watch them all.
your videos are so darned good. You explain everything so well. You must have a huge fan club! Thank you!
Have been preparing to swap my Volvo engine over to double 45 DCOE's. Your series have helped me rebuild them and I think this series will be a massive help with adjusting them. Thanks a lot!
Good to hear, thank you
Very useful, thanks for taking the time to make this film.
thanks
These discussions are 1st class. Thank you. I would like to see a SU vs DCOE comparison. You have done in depth on each and can offer deep insights on this IMO.
This video is going to be absolute gold when I'll tune my 1973 Fiat 124 spider!!! Perfectly explained step by step! Thank you so much!
Another great informative video Steve
Thanks
Best carburetor for any application! Infinitely tunable but you must know how!!
Fantastic explanation it's sounded so easy if we carefully listen and follow, tqvm sir ❤❤
Many thanks for the video, i felt like i needed to take notes - i suddenly felt the urge to fiddle with my own webers on my alfa!
Thanks for the comments, and yes do so
@@D3Sshooter I wanted to ask you - I have webers 45 (not sure of choke) and i was checking the idle jects and they are 50F8 - my engine is a 2.0l and im running to sets of dcoe. I have to open the idle screw more than 2 turns to keep idle. Do you think the idle jet could use a size increase? Thank you! I absolutely love your approach you are very talented.
@@AM4project Thank you, if the progression works smoothly, then don't worry about it.
@@D3Sshooter i have a bit of a flat spot (bogs down) if i depress the pedal too quickly
@@AM4project , I assume that is under acceleration, that typical relates to the acceleration jet size which is to large... in essence you flood the engine with fuel squirted by the acceleration pump through acceleration jet into the barrel... The engine is flooded in a fist instance with fuel , but after a short while that fuel starts to be consumed and gets less, at that time the engine picks back up... Reduce the acceleration jet with 5 as a starter. the other problem could be that its not enough fuel injected, but here the engine will bog and then slowly accelerate...in this case increase the jet by 5. There are other ways to adjust this by changing the hole in the accelerator pump feedback jet so that either less fuel is pushed back in the well ( in essence increasing the volume of the injected fuel) or the opposite. If acceleration is an issue without a quick depressing of the throttle then you have either an issue with the main jets or emulsion tube type.... In each case , to lean mixture during acceleration will be noticed in puffing in the carbs, a to rich mixture during acceleration will be manifested by black smoke in the exhaust and bangs in the exhaust ( on burned fuel that ignites)..both situations will cause the engine to bog down momentarily
Keep up the good work, love the vids, you should be on tv.
Maybe one day!
Spanish made Weber DCOEs 45 152 G etc have a finer thread on the idle screw, 2,5 turns works instead of 1,5 turns mentioned in this excellent video.
I think the thread is the same, its the taper of the point that changes? I just changed mine and its a bit easier to adjust now as they're not so sensitive to tiny changes.
My experience with the Spanish weber is that they are sub quality , I had one for a test, bad channels , poorly machined and nothing then trouble. Maybe I was unlucky, but you are much better off buying a real italian weber and rebuild it...
Dellorto emission carbs have a fine thread aswell
@@D3Sshooter I think they have rectified the issues and I have had no issues to date with the latest 152G model (4 progression holes).
I just tuned a set of spanish carbs on an engine dyno i found the 3/4 to 1 1/2 turns was spot on, i dialed in at around one turn on each
Hi, thanks so much for your videos, which are so helpful to me (especially SU's and Webers's carbs). I'm really waiting for the part 2 ... to help finally set up mines !
Great information on weber tuning.👍
Thnak you
Excellent video. Clear, concise, very informative.
Thank you for such excellent detail of this subject. The best video on TH-cam regarding this. I have twin weber 45 DCOE that I bought for my BMW 1975 e10 (2002) over 30 years ago and could be calibrated or find someone to do it for me. Remove it from my car due to that and put aside the carburetors. A few months ago after restarting the car, reinstalled them back in the car and was hoping find some info on internet to be able to assist me to calibrator these twin carburetors. Watch so many videos but non explained the was you did. As I said earlier. Yours is The best video on TH-cam. Thank you very much. Have a great day. Regards JZ
Thanks for another great video, Has taught me plenty and with changing idle jets on mine, I have achieved a great setup..keep up the good work..
I have been tuning the low speed circuit for over 20 years. Idle jets. Idle feed restrictions. Did it on a holley on a 429 ford . Went from 0.031 idle feed restrictions to 0.036" idle feed restrictions by test driving and drilling them 0.001" at a time. The car owner came back with a complaint. He can't pull away from any stop no matter how he feathers the throttle. He spins the rear tires. Did that to a straight six dodge dart. Now it will burn rubber too.
When i use a air fuel ratio gauge with an oxygen sensor in the exhaust. I bring the rpms up to around 1700 rpms. Which in just below the speed the primary main jets start to trickle fuel. That lets me know if the idle jets are lean or rich. Thank you for the great video. Years ago i talked to a nascar carb manufacturer about billet metering blocks for holley carbs with vacuum operated plungers to shut off the idle circuit during engine braking on short tracks where flames come out the exhaust as the high manifold vacuum just pulls all kinds of fuel from the idle feed holes. He liked the idea. About 3 races from the end of the next season. Which was a short track. Close to the end of the race. The announcers said the car out in front does not seem to have flames from his exhaust during cornering. They pulled up the pit records. The guy in front was pitting every 56 laps. Where everybody else was running out of fuel at 51 or 52 laps. Fuel mileage during a race can win a race. Careful searching might find weber idle stop solenoids. With an adjustable vacuum switch hooked to manifold vacuum. One could set the switch to turn off the idle stop solenoids during high speed engine breaking to save fuel during a race. I also like using the weber and solex air bypass screws as that allows me to preset the throttle plate to expose exactly enough of the idle transition slots or ports. Getting the best fuel economy and instant throttle response.
Thanks for the comments , a nice write up
Wow. Absolutely fantastic video and explanations. I very much appreciate your patient approach.
my pleasure
Simple and easy wonderful lesson. Cheers Steve 👍 💯
Simple is who I am, I had once a professor who stated " the beauty of engineering lays in simplicity"
Very clear information theory and practice
Thank you
Excellent instruction, thank you
Can’t wait to see the next part :) great tutorial - exactly what i needed - Thank you :)
Thank you for the comments. Soon
@@D3Sshooter hi! When is the next part coming? Great videos! Highly appreciated
Another handy item for adjusting carburettors is the British made Iain Tyrrell, however, that is quite expensive and can't be stored in your toolbox.😁
thank you
Your videos are first class, Steve. Even my wife likes watching them and she has zero interest in cars.
I was a little surprised at your comment about the Spanish Webers . Can't be that bad as they have been making them in Spain for 30 years and they're still in business.
Regarding the Idle Mixture Screws, if the Weber is a 151, these screws will be the finer thread and taper allowing for finer adjustments but requiring more turns. one and a quarter with the coarser screw would be about three with the finer later type.
BTW, Steve, I have a very similar set up to your GT for track days and vintage racing but mine is a roadster.
Greg.
Thank you for the comments. Indeed there is a difference between them/ My experiences with the Spanish Webers is really bad... I had two the DGAS ( its even inn a video where I show the poor quality ) and a DCOE45. Maybe I was unlucky.
Yes, the later Weber 152G are the ones to get now. Four progression holes and yes they now have a "finer" taper on the Idle mixture screws so more turns out required.
Steve - FANTASTIC video - I was going to ask about the Spanish Weber screws since I realised they must be different while trying to adjust mine, but I see that question has already been answered here. Look forward to the next instalment!
Thanks for the comments and indeed David
Was desperately waiting for your video about this topic! I just finished my 1979 VAZ 2103 build with DCOEs and as expected yet they run like shit 😂
Higly appreciated, I really value your way of teaching 👍🏻👍🏻🙏🏻
thank you
Thanks, good to refresh my recollection before the next sync and check.
Fantastic video sir you are improving our knowledge a very good teacher.👌
thank you
Great tutorial. Thanks.
Thnak you
super video weer! dank!
Thanks a lot for this video, I'm tuning a pair of 45 DCOE Sherriberg (the chinese replicas) and now I know that I need one or two sizes up the current defaults 55F8's. Idle gets good at about 2,5 turns on the mixture screws, AFR gauge says about 13:1 at idle speed but once I push the throtle only a bit, it goes down to 20:1 and the engine hesitates and backfires. I have a set of 50F9's and another set of 60F9's. If none of these works I'll have to buy a new set lol, and again thanks, you strongly cleared my doubts!!
great info
Excellent video, thank you so much for the explanation on how to adjust the Weber side draft. I just installed a 45 dcoe on a datsun L20B and the progression is way to lean. Your videos gave me what I needed to correct the issue
Super easy explained. Tnx
Your the best 👊🏽🇹🇹
As always very good thanks
thank you
Very good information regarding cam specifications, even with the difference in tuning my boosted engines requiring less duration and to my high comp NA the tuning is different on those factors you covered. Great video Steve 👌
Thanks for the comments,
Excellent sir 👌
Love your work 👍
Thanks, you must be one subscriber that always answers.. That is nice of you - TXS
@@D3Sshooter My pleasure.
Idle and progression are the MOST important circuits!
yes they are
Bom dia para todos!!!
Gostei muito da aula de calibragem desse modelo de carburador duplo.
Foi excelente às dicas que foi mostrada e a perfeição de como se deve ser feito o serviço com a mais perfeita calibragem.
Adorei o vídeo 👏
Thank you really, Mr Steve. Your videos are superb and the knowledge you provide us is really appreciated ! Thanks again!
My pleasure
Brilliant video 👏👏 can you make part 2 please 😁
Nicely explained Steve , thank you .
Do not worry about your 'English ' , I understand you clearly , no problem . My Dutch is completely lacking ... the same as nearly 100 percent of your watchers most likely !
Engines , whilst I know for fact understand cuss words , those words can be in any language you choose ! Kinell
Thanks for the comments
Excellent explanation Sir.
I like your no nonsense, calm way of explaining how things work.
To me, a carb is a mysterious piece of equipment and most of the time, I used to ''adjust'' it by the feel of the pants or how it sounded.
Sounds right? lets go! LOL
Not exactly scientific and I most probably lost power.
I learned a lot
Thanks
Thank you so much...a good mechanic does it indeed on the feel
Great explanation about the relationship between the idle jet and the number of turns needed on the idle mixture screws.
Also good you highlighted the importance of the position of the butterfly with respect to the progression holes - as per the Weber manual the edge of the butterfly should completely cover the first progression hole. The problem is that if you then adjust the idle speed using the idle speed screw this will move the edge of the butterfly - too much adjustment could lead to a less than optimum performance.
Indeed Andrew, and thanks for the comments
I had this same problem when adjusting the idle speed (butterfly) screw. It is impossible to see properly when the carb is mounted on the intake manifold. The way I worked around it is:
When the carb is off the car adjust the idle speed screw until the first progression port is just about to be uncovered and mark the position of the screw relative to some convenient feature on the carb.
Then back off the idle speed screw while counting the number of turns until the butterflies are just fully closed. Make a note of the number of turns on a pad of paper.
Each time you make an adjustment write it down... +1 -1/4 +2 -1/2 (or whatever)... takes some concentration but once you get in the zone it goes pretty quick and you will know where you are.
If you lose your place, like you get a phone call (aargh!), just back off the idle speed screw until it it just touches the lever and start over.
Appreciate it!
Thanks for the comments
Can you please group all the DCOE 40 videos into one playlist? Thanks again for putting these together. Super helpful!
Yes , I will good idea
Muy bien!!
my pleasure
Thank you so much for putting these videos together. I recently bought a Low-cost 7 with twin Weber DCOE 40s and with your help I was able to get them tamed. Looking forward to the next video. 👍
Excellent videos. Thank you! What is the small hand held shop light you use? I've searched and don’t find anything like it. Thank you🥽
Thanks for all the help! I was wondering if tuning the idle mixture to achieve max vacuum on the manifold after the throttle valves is a thing on dcoes. I see people do this on other carbs but not dcoe/dhla
Great video thank you! So when looking down into the progression holes i sould only be able to see the butterfly in the closest hole to the engine? Correct?
Love the videos - amazingly helpful and I have learned tons. Thank you. Quick question - just bought a used set of 45 DCOEs for my Datsun 510. Previously had 40s. I noticed the 45s do not have a secondary Venturi tube that can slide out (as per my 40s and in your videos) however they have a bolted in support for the main jet. The main venturis appear normal. Is this a factory option or a modification by the previous owner? I have pictures but not sure how to send them to you. Much thanks in advance. Jeff
Thank you Steve! I feed your videos extremely educational. Does the 3.75 to 1.5 turns rule apply to the older DCOEs that have the idle screws recessed within a cavity in the carburettor and an O-ring underneath the screw head? I have read that this is the older type of DCOE (non-emission type). Thank you once again.
Hi i am pablo from argentina i have 2 weber 45 dcoe into my fiat 128, i have a problem when i stop my engine the fuel level of the carburator goes down if i leave one day to another day and i dont know from where the level goes down, aparently goes to the cilinder but i dont know in wich part of the carburetor leave the fue into the cylinder when the engine is stoped. Thanks in advance and very good explained.
the only issue is we cannot give more than 1 thumb up 😢 for everytime i watch this.
Though i run a Mikuni, the basic tenents are
the same.
Brilliant video, I’ve got a DCOE connected in a draw-through supercharged setup. How does the emission control screw work? Would really help me pass the MOT I think.
I have 2 Italian 40DCOE 27's & 1 40DCOE 2. What are the main diff in the bodies between them? Not the jets etc. I have 3 on a TR6 cyl motor. Any ideas? Thanks. I love your vids. So clear. I have learned tons. Please keep them coming.
hi, thanks for your videos, on 14 minutes, you say after adjusting them go back to all the screws and turn them in a quarter turn each however in your live running adjustment later on you did not do that, can you confirm ? many thanks.
Hello my good friend, I'm revisiting this video again. Do you know if the same idle mixture screw principles apply for Weber 38/38 carburetors?
So you keep opening the idle mixture screw until the RPM stops increasing?
Hello can you help me on a carb for an 12a mazda its smoking because i think it gets too much fuel 🤔
Do you have part 2 out on tunning the Weber?
Hi Steve, are you running the SU pump? I was trying to autocross Sun. and kept running out of fuel. I have a facet gold top @3.5psi Mikunl phh44
im trying to find out if the SU pulls and pushes? The facet model supposedly has 2' dry lift and is in original mgb position.
More more more:))
I have a set of 40dcoe for my alfa spider.
This is good info. Its been too long since I played with these carburetors.
Any chance you can do a video on solex 42 ddhf ? Or something similar.
Thanks , a solex 42.... if I have one I could yes
How do the idle mixture screw turns translate to the spain DCOE’s with a finer thread? This is an Italian carb correct?
Thank you for such an informative video. My 4 cylinder on 40 mm dellortos bogs when the throttle is opened quickly but fine when opened smoothly. Does this mean it’s running too lean on the progression ? I will check the number of turns on the idle as per your guidance
hmmm, when it bogs it can mean that the acceleration pump injects to much fuel, especially if after the bog it picks up again and you have a black puff . if it remains slow and blows back in the carb its to lean (acceleration pump)
@@D3Sshooter thank you for your help.
Really nice video, I have twin 36 dcnf on my 1.1 Fiesta, all running standard jetting from the Ford factory parts.
I'm no expert and took a minute to get her running nice, I will say though my idle screws are around 3 1/2 turns out on most and I think 1 is on 3 turns.
Would you say I should experiment with larger idle jets or is it different depending on carb types, dcnf dcoe ect.
Current idle jets are a 0.47, she does cough a bit when cold but 20 seconds of choke and ready to drive ( daily car )
Thanks very much and great videos as always :)
Hi, remember that thet 3/4-1.5 turns only apply to the DCOE, much depends on the threat that those screws have. As far as I recall the DCNF has a finer threat , so that would be normal, if you engine progresses nice and smooth then there is no need to change that
@@D3Sshooter thanks very much for the quick response Sir, yes that makes sense. I will leave her be as it seems to run okay in that case.
Thanks and have a nice day.
Hello sir!
Could you please share if having your Weber on such a tilt angle affected your tune?
How if you had to, did you compensate?
Ideally you would have it horizontal, I had no negative effects on it, Keep in mind that on a race track the fuel bounces left to right anyhow ( in the curves). On the straight that could be a problem/ just adjust the float level accordingly. Of course its better to have them horizontal..
i have mine turned out to 3.5 turns, on a draw through turbo set up. how many sizes is that so i know which size idle jest to get. thank you!
Some have smaller treading then others so it can be that yours has that small tread so 3.5 is ok. if it is standard tread then you should increase the idle jet ( fuel) with one step up
What was shared was max in: 1.5 turns and max out: 3/4 turns. This is for the older Italian DCOEs. What should the figures before for the Spanish 151s?
yes indeed that is for the original webers, it all depends on after market types on the shape of the screw and treat
Thanks for your reply Mr Steve. Have you got the approximate figures of an original Spanish 151s?
Please can someone help - I’ve set up a Weber dcoe 40 on my 998 fast road. Kent 266p and Peter burgess fast road head.
I’m using a 45 F9 for the idle and on slow progression it revs nicely however if I dump the throttle it bogs complete and nearly stalls…..
Current set up below, do I need a richer jet, can someone suggest what I should try…. I have a spare 50 f2 but I guess that is too lean?
Choke - 32mm
Main jet - 140
Air corrector 175
Emulsion tube - F2
Idle jet 45 F9
Pump Jet - 45
Needle Valve 200
Thank you!!!!!
have look at one of the video' that I made on tuning the carb for acceleration and driving on t he track... Is the acceleration recovering after some time ? In a first instance I would check that the acceleration pump pushed fuel out the two nozzels on the top... you can do that without a running engine... just push that throttle and look for the squirts. The squirt can measured but if they are shortly present and not to excessive then that is ok.. If not present h then you either have a ripped acceleration pump membrame, or the feedback valve stays open. If it is to much you will have to adjust the feedback opening.
@@D3Sshooter I will check that later, it is a brand new (Italian) and recently refurbished so I assume everything works as it should. The acceleration comes back if I come off of the throttle for just a second then it rockets….. I assumed it wasn’t getting enough fuel on the progression?
Why 55F9?
Hello Steve, Any ideia when part two will be up?
Thank you for the comments. I have been stuck with a real cold and will start the next video in a couple of weeks...
Steve all the best for 2023.
Any news on the second part of the video. All the best
@@crunchfreitas7507 Thank you, I am stuck with the flue since 2 weeks..., also the tracks are closed at this time, as soon as the tracks open up again I will take the mgb for a shake down , and at that time i will work the carburettor part two... I can't take the risk here on public roads as they are very strick ( the cops)....If caught you lose your license to drive and your car is confiscated and publicly sold....
I know this is being very picky
RPM stands for RevolutionS Per Minute, not per minutes
yes indeed
@@D3Sshooter forgive me for bringing it up, I love your videos - but so many people do it, it's got irritating
@@Da5idc no problem , that is how i learn to speak better as a none native speaker ( from you comments) txs
@@D3Sshooter Or you could say 'revolutionS per 60 secondS' and confuse everyone! :D Or 20 RPS (for 1200 U/min)... languages are FUN!
Very interresting i am going to set them.thanks good information
Thanks for the comments
Ok saw ,i try .work the best now .but the spark plug are dusty black .check my ignition good spark .fuel 4 pounds
I have 125 jets 190 air ,f16 emicion tube
Weber are 45 dual.1.8 3tc engine has good power .up hills and start right up,you thaw what can be .i all saw sincronize the carb.
I have some questions for you before i start spending money on this project, do you have an email i can write to? i would love some advice with your expertise :)