Don’t let anyone give you crap about over explaining a damned thing. I don’t know what the hell I’m doing but I’m learning and anyone that already knows this stuff shouldn’t need a video nor criticize anyone’s teaching methods. They should make their own videos their way. I learned some things. Your way is fine and I’m not going to have to take my car back to a mechanic after just getting robbed by one for double the expected budget for getting my car running. I appreciate it and thanks.
Dude my square been bogging down for a little while now it would fall on the bumper if you floored it and I watched this video last night and today I checked mine and my set screw was loose and flaps had no tension what so ever so I set the tension and locked it down and holy F-ing shit it runs like different damn engine!!! Thanks for the info !!
Happy to help. Don't be afraid to play with it, but it is very delicate. Make adjustments in 1/8 turn increments to avoid overstretching the spring. No more than 1.5 turns total or you may ruin the spring.
I drove my 1966 Impala SS with a 396 for many months with a bog problem until I did this adjustment somewhere around 1974. I have thought the lack of knowledge of this adjustment is the main reason for people dislikes of this very good carburetor. I had a book on this carburetor it had a chapter on how to adjust it for max performance and great gas mileage.
Right on the money. Motors and Chiltons manuals, as well as Standard Jiffy Kits listed an air spring wind up spec. I found that it was a good place to start. I don't know if it was for fuel economy or emissions, I always found the spec to be a little too tight. As you said though, it requires a fine tuning to get the best out of the secondaries. Thanks for the vid. Brings back a lot of good memories of working and modding OJets in the 70's.
Thank you for this video. Great explanation. I like you describing the different ways to view the tension spring, the incremental approach and your sense of humor! You’re helping me and my 66 Tempest Sprint.
To add to this adjustment video, "critical". Make sure you're holding the A/V screw, (with your flat blade screw-driver), BEFORE loosening the allen set screw. If not, the screw will unwind, and you'll be screwed.
Ah yes, when the younger generation actually learns how to do something that used to be a common tune up adjustment. I swear a buddy of mine thought I put a cam in his late 70s Cutlass. All I did was change the oil and filters, clean up and gap the plugs, made this same adjustment to his carb, and cleaned up his battery terminals.
Mine only bogged when racing and it was always a stuck float.I was about 17 then and even though I had already rebuilt 2 small block Chevy engines by then I was winging it on carburators.
Depends on the application. If the engine can handle the big doors flopping open instantly then having them looser and or removing the pullout linkage is the way to go. But on a street application like mine, it bogs horribly that way.
My vacum diaghram doesn't release the rod that opens the secondary flappers?? Is the diagram broken ?? Even when warm it still doesn't release the rod!! Thanks bud
I have a 1966 Olds Toronado with a 425 and a QuadraJet Four Barrel. The car starts and runs great at idle. It won't bog down even if you jump in at idle. It looses power at 40 mph, but runs fine down the street before you hit 40 mph. Actually, it won't pass 40 mph. Could this be its problem? The plugs, wires, points, and cap are all new, so it can't be in the firing part of the car. I'll try this and see what happens.
@@jordanwiley4582 Yeah, I did and it is clean as a whistle. We follow this suggestions and we still have the car basically give us problems at 40 mph. We don't know what else to do.
One more question friend, I'll tell you, I have a Rochester Quadrajet carburetor and I want to change the primary nozzles along with the primary needles, and since there are different numbers of nozzles and primary needles, I have to deduce that depending on the number of nozzles, I must set the needle number equal to the nozzle number? I mean, if I put number 0.72 primary nozzles, should I put number 0.72 primary needles? I understand that in this way, the idling engine has the primary nozzles blocked with the primary needles, since they are of the same diameter, and that when accelerating and losing vacuum, the primary needles begin to rise, allowing fuel to pass to the primary jets, is that correct? all the best
The primary metering rods are numbered in pairs, look up a chart that has all the numbers. The rods are also tapered a d have steps on them. They will not be the same diameter of the jets. The jets are numbered the same as any other carburetor. Look for a quadrajet jet and rod tuning kit if they still make them. Depending on what year quadrajet you have you can adjust how far down in the jets the rods sit by adjusting the Adjustable Part Throttle screw that is under a shiny aluminum plug on top of the carb Infront of the choke horn. It's usually covered by the air cleaner gasket.
That is why I doubt what type of numbering in primary nozzles and primary needles, my primary needles, are held in a firm position with a plastic washer that does not allow adjustment up or down
@@franciscotrujillo4961 do they have spring to them? They should have a spring in the power piston assembly. During cruise rpm the vacuum keeps them in the jets so you use less fuel. When vacuum goes away such as transitioning from idle to wide open the spring pushes the rods out of the jets and gives more fuel on the primary side.
@@jordanwiley4582 Yes, exactly, it is a calibrated spring, and it effectively does what you say when the vacuum decreases when accelerating, raise the needles so that they let the fuel pass through the nozzles to the primary jets placed in the primary throats
to make space on your phone first get an SD card then go to settings then apps and the ones the say they on the internal storage and aloud , Move to SD card same goes with pictures and films.
Sorry to burst your bubble but that secondary air valve spring has a pre-set value & has nothing to do with the infamous Q-jet bog. That green rod that goes to a vacuum pot is the culprit. Manifold vacuum holds the air valve closed & bleeds off vacuum at a prescribe rate when you go to full throttle to allow the air valve to open as required. If the diaphragm is ruptured the air valve will open way too fast causing your bog. Check the rebuild sheet on that particular carb for the secondary air valve tension spring adjustment. Next use a vacuum pump with a guage and see if the diaphragm is ruptured (wont move the little green rod). If the rod moves it should hold the air valve tightly closed until the vacuum source is removed. If not follow the adjustment proceedure on the rebuild sheet. If the diaphragm is working check the function by removing the vacuum source to see if the diaphragm releases slowly. If it doesn't pass the tests discard & get a new one. Quadrajet parts.cm is a good source.
Sorry to tell you, but the spring is fully adjustable from slack all the way to 1 full turn and is a large cause of the bog. But, as you said, the opening rate of the dashpot (front rear or both) also comes into play. But spring is easier to adjust. And free.
What you're talking about that causes the bog... Or it doesn't have that layout anyway like the ones I have for my 86 K2500. My 85 C30 though could be a different story, but I've yet to pull the air cleaner housing off the 454 in the 85 so maybe I'm just putting my foot in my mouth here.
@@jordanwiley4582 LOL That's how educated some of the "Holley" fans are. They can't even spell it. Quadrajet has almost "10" letters, but Holley has only 6, makes it much simpler. :)
@@imaouima If you're a GM fan, have a street car you actually "drive", and want to make upwards of 400HP, but need it drivable too, a QJ is a great carb. Throttle response, mileage, and some power too. Of course it needs to be tuned, and isn't as simple as a Holley, but there's enuff info now to educate the un-educated. Of course if you're a Chevy guy, with an L-78, or 302 Z, that came factory with a Holley, well that's different. Or a Ford, or Mopar fan, you have alternate choices too. But it still annoys me with the ignorant, and un-trained to make comments like, "throw your 750-800 CFM QJ away, and bolt on a 600-650 Holley for more power". (Sure, you'll be alright)
This video about this adjustment (And tweaking the actuator rod like we did) is about 25-30 years too late... Who runs a Quadrabog these days anymore? If you do, you are WAYYYYYYYYYYYYYYYYYYYY behind the curve.
plenty of people that A) want a versatile, cheap, and large cfm capable carb B ) people in the FAST drag class c) people who want actual acceptable mpg from a carb
@@jordanwiley4582 Other than NHRA Stock classes that mandate the OEM carb... there is literally nobody. The old 3310 Holley (or 6210 if you wanted to stick with the spread bore crap) ran better, was easier to tune, had far more adjust ability, got excellent fuel mileage and generated more power than ANY stock Q-jet. I played with Q-jets for years a couple decades ago. Probably still have a secondary metering rods laying in my box. All hand modified with different tapers and diameters. Long before you could buy them on Amazon. Put a Sniper on it and end the pain. It's 2021.
@@johnnydsworld710 if you actually know how to work on them, you wouldnt be bashing them. For daily driven applications under 500hp (over that they require serious not worth it modification), they are the best choice short of fuel injection. They are the easiest to tune and adjust, you cant over carb an engine with them, they made millions of them and people like you just throw them in the trash so theyre literally a dime a dozen. Theyre the best all around carburetor. It's fact. Qjet for driveability and reliability Holley for all out power Edelbrock if you have brain damage That being said I've had qjets, holleys, and worked on cars with edelbrocks. I like qjets better than the other two, but my 70 and later 71 t bird that had 600 holleys ran perfectly fine as well.
@@jordanwiley4582 You are making some delusional ASSumptions there bud. You are not the only guy on this planet that can work on and tune a Q-Jet. But I am sure in your mind… you are. And nobody is bashing them. But the facts are the facts. No matter how blurry your videos are my friend.
@@johnnydsworld710 Hmm, soooo, if YOU ASSume that nobody is bashing them, I suppose that would mean you're a NOBODY then, huh?? Why would anyone want to listen to a nobody like you? Here's a FACT for you....they wouldn't!! 🤣🤣
