The only thing I wish was in this was the damper in the top of the piston. It works like the accelerator pump on american carbs but no need for a linkage. Very smart design. Love the quality of this video.
Please, do one on setting fast and slow idle, carb linkage, using the x-screw adjustment for air to fuel mixture, balancing 2 HIF carbs... that'd be glorious. Thx.
Aloha yes that’s all well and good 🌺good description of that part of the operation of carburetor 🌺what you did not mention is how to adjust the bottom dial how many times to equate the air and fuel and also to mention the Float bowl if the float is too high it’s going to run to 💰💰💰Rich 💰💰💰 or if it’s to low going to run to run lean It has to be in its proper place you did not mention or explain any of this which would have been greatly helpful 🌺🌺🌺
Basicaly it is a vacum carburaetor....nice..... i like the way u explain... But i have a guestion...which one is better...this su carb...or regular car carb like maybe 5k or another downthhrough carb that dont use needle?
The engine side vacuum is not 'pulling' the air into the carburetor, the higher outside (atmospheric) pressure is 'pushing' air into/through the carburetor throat toward the vacuum. and creating a low pressure area above the jet which causes the higher atmospheric pressure in the float bowl to 'push' the fuel out of the jet and into the incoming air stream.
It’s to slow down the upward movement of the piston so when you crack the throttles open quickly, they are able to respond without jumping up too fast and causing a lean condition.
I appreciate the elegance of the constant depression mechanism. But can anyone explain to me why it is necessary? I mean, why not just attach the throttle cable to the piston, rather than attach it to the butterfly > depression > vacuum chamber > piston?
because the butterfly opening and and how much the needle is raised out of its seat are not directly proportional to each other. and even if you managed make a complex enough linkage to do this it would vary across all engines
The piston gradually rises with vacuum and that stops the engine getting a flat spot if you push the throttle wide open suddenly. That is what used to happen on some motorbikes with an Amal carburetor with a piston coupled directly to the accelerator cable. You had to twist the throttle gently or the engine would cut momentarily.
dead accurate. Have a friend with an 80s dodge 360 P/U with a rochester quadrajet, great motor, but if you slam your foot to the floor, the motor hesitates for just a split second then the powerband kick in. "Are you sure thats what you want? OKAAAY let go!"
What makes the idle go crazy and the Pistons clack clack clack clack clack clack clack clack clack clack it was fixed and it did it again obviously the mechanic got the money the car was sold and we bought a pinto
I've taught college for nearly 30 years, and this is among the most coherent explanations of anything I've ever heard. Well done.
Three cheers for 'Skinners Union'. Great explanation.👍
Thank you for doing this video. I now understand what my twin SUs are doing!
What a master class. This should cost money to watch! Thank you so much.
Great video.. I have 69' datsun roadster and never had a full explanation of how they work. Great video!
He is the Morgan Freeman of British Motor Engineering! More videos please!
Great explanation of SU carbs! I love this channel. Keep up the great work!
Thank you!! I've been looking for a simple explanation of the SU's
The only thing I wish was in this was the damper in the top of the piston. It works like the accelerator pump on american carbs but no need for a linkage. Very smart design. Love the quality of this video.
I was not expecting a meteorological lecture today. Seriously, though, excellent video. I really learned things.
Very well explained. Thank you.
Blaine, thanks a lot for this informational video.
Wonderfully explained even i understood that. thank you for sharing.!!
I had one on a 1980 shovel head in the 80's and never had an issue with it. It's more carb than a four speed tranny can handle in my experience.
Please, do one on setting fast and slow idle, carb linkage, using the x-screw adjustment for air to fuel mixture, balancing 2 HIF carbs... that'd be glorious. Thx.
The best explanation ever on carb.. Tq
Thank you very much. Perfect explanation
Thanks for this. Ive been looking into side draft for my 2.5l iron duke camaro.
awesome job. very educational. I really appreciate it.
I love carburetor, especially sidedraft carbs on in line 6 cylinder engines. I sometimes wish I had on my datsun 280ZX. Non-Turbo thank you.
Amazing! Thanks for the help!
Nicely explained
Great Job!
When the Mr. Bill show was cancelled, Mr. Hands got a new job showing us Carburetors.
beautiful explanation,thank you
AMAZING!! , MORE ACURATE THAN A MODERN FUEL INJECTION SYSTEM.
NOT BAD FOR A PREHISTORIC DESIGN.
I get it! Great YT post. Thank you Sir.
Thank this video is amazing
7:48 I had a 72 240z with side draft carbs. I always wondered what lifted up the piston to allow more fuel to go into the engine.
WOWWWW thank you for explain!! I wonder always also: how you do find out/make this :-))
Nicely explained! would it still be working if mounted horizontal? I ask because I wanna install it in my 69 vw beetle
what kind of Cfm do these make? im guessing in the 175-225 range?
Thanks man
Aloha yes that’s all well and good 🌺good description of that part of the operation of carburetor 🌺what you did not mention is how to adjust the bottom dial how many times to equate the air and fuel and also to mention the Float bowl if the float is too high it’s going to run to 💰💰💰Rich 💰💰💰 or if it’s to low going to run to run lean It has to be in its proper place you did not mention or explain any of this which would have been greatly helpful 🌺🌺🌺
What about intake manifold vacuum doesnt that equate to the SUs piston function?
Basicaly it is a vacum carburaetor....nice..... i like the way u explain...
But i have a guestion...which one is better...this su carb...or regular car carb like maybe 5k or another downthhrough carb that dont use needle?
Great, but I why not activating directly the piston for accelerating ?
The engine side vacuum is not 'pulling' the air into the carburetor, the higher outside (atmospheric) pressure is 'pushing' air into/through the carburetor throat toward the vacuum. and creating a low pressure area above the jet which causes the higher atmospheric pressure in the float bowl to 'push' the fuel out of the jet and into the incoming air stream.
Wrong
Great explanation. Just wish you`d added why the dashpot needs oil in it.
It’s to slow down the upward movement of the piston so when you crack the throttles open quickly, they are able to respond without jumping up too fast and causing a lean condition.
I appreciate the elegance of the constant depression mechanism. But can anyone explain to me why it is necessary? I mean, why not just attach the throttle cable to the piston, rather than attach it to the butterfly > depression > vacuum chamber > piston?
because the butterfly opening and and how much the needle is raised out of its seat are not directly proportional to each other. and even if you managed make a complex enough linkage to do this it would vary across all engines
The piston gradually rises with vacuum and that stops the engine getting a flat spot if you push the throttle wide open suddenly. That is what used to happen on some motorbikes with an Amal carburetor with a piston coupled directly to the accelerator cable. You had to twist the throttle gently or the engine would cut momentarily.
Thanks for the responses to my query. So, essentially, it is a mechanism to enrichen the mixture temporarily on acceleration. That makes sense.
dead accurate. Have a friend with an 80s dodge 360 P/U with a rochester quadrajet, great motor, but if you slam your foot to the floor, the motor hesitates for just a split second then the powerband kick in. "Are you sure thats what you want? OKAAAY let go!"
100 times easier than a modern injector.
How can anyone dislike this? There's something seriously wrong with the human race.
So probably not great for an individual runner setup. Seems like the piston would be bouncing with the fluctuating vacuum.
I notice my 240z ran smooth and never flood. Americans car makers could have save a lot of fuel if they had used side draft cabs.
What makes the idle go crazy and the Pistons clack clack clack clack clack clack clack clack clack clack it was fixed and it did it again obviously the mechanic got the money the car was sold and we bought a pinto
na m8 XD
So these carbs need no motor to function? BS