Can someone provide me the specifications of this carb? Idle tubes etc? It is for a bone stock engine. I have a commercially remanufactured one, and it's not running well. I made some changes, but it's now worse.
From the 1969 Chassis Manual, they don't list the 7029241. https://www.teambuick.com/reference/library/69_chassis/files/64-d.php
I'm sorry, I mean idle tube sizes, dcr, main air bleeds etc. Jets and rods I have correct. At this moment I have: Idle tubes: .0354 (from metric 0.9 mm drill) DCR: .0472 Main air body: .043. Upper idle air .052 But having doubts.
I don't think you'll find that written up anywhere. Maybe Cliff might know, or someone would need to measure an original carburetor for you. I would look for a later year Q-jet. They have stronger floats and adjustable rod height (APT)
You are finding out why I avoid commercially "remanufactured" Q-jets. They mix and match parts, which never works out well for the end user. You can't just come in and try to duplicate all the specs and come up with a perfect end result just matching the specs of an original unit. They are parameters that aren't the same in the parts being used. The parts may look similar or even the same, and bolt together, but they are not the same. The APT system in the baseplate to mention one. The companies that "remanufacture" them remove the post from the bottom of the power piston. This drops it to the lowest position and many of the early APT Power Pistons are shorter than the variety that didn't use APT. Since the metering rods are now bottomed out and too deep in the jets it cuts off the idle fuel past the jets to the idle tubes, or basically you now have the MINIMUM metering area for part throttle and fuel that can get past the jets to the idle system. Since that deal is all botched up they then come in with HUGE idle tubes and MASSIVE DCR's to try to salvage some idle fuel to the mixture screws and transfer slots. This brings up another problem. The location and length of the transfer slots is NOT the same between all part numbers, so once again more problems are introduced which require custom settings of everything else to get them to work like they are supposed to. I could go on here for many pages here as I'm just touching the surface about what total pieces of bovine excrement remanufactured Q-jets really are. Bottom line is that commercially remanufactured Q-jets and JUNK, and if you are going to spend time trying to make them work following standard guidelines to set them up in almost all cases it will NOT be successful, or at least your end result will not be nearly as good as starting with a good original unmolest core in the first place. So what you end up doing is to start throwing MORE fuel to the idle and off idle circuit to compensate for fundamental issues and incompatibility with the parts being used to build the unit. It's pretty much trial and error, but if you do what the companies did that built those POS, just make it "fat" everyplace and at least you woln't have nearly as many running issues as being too lean........FWIW.......
Let's not jump the gun here, I installed my old carb today and nothing. Worked before. Something went wrong with my ignition system the last few days. Carb could be wrong, but first I have to address other issues. On topic, I also reached out to quadrajetpower.com: "Hi, my notes show this original calibration Upper main .039 Lower main .058 Idle tube .032 Idle air were similar to yours. Smaller main bleeds will richen the mixture, which should be fine for todays fuels." My lower main was smaller, so I enlarged that.
Not "jumping the gun" here. You ask for help and I'm providing deadly accurate information far beyond the scope of others who will read this. Remanufactured Q-jets are and always have been pathetic for quality and I mentioned some of those reasons in my last post. The mixing/matching of component is the first death sentence for them. I stopped working on them decades ago and not because I don't have the skills to get them to work correctly. I've found that it is ALWAYS better with much less time invested to just get a complete/correct core right to start with. With very few exceptions they are spot on right off the bench, vs having to spend a lot of time in multiple areas trying to get them to do what they are supposed to........FWIW.....
Well kinda, The car idles steady now. I can kill it with the mixture screws and I pull well over 20" vacuum. (So I have the intial problem sorted, it didn't idle steady) The ignition problem started simultaneously with my work on the carb, so at first I was looking at the wrong cause, but that is sorted now. Don't get me wrong, I really appreciate your information. It really helped me to review my carb. For example, this thread shows some pictures of an original one: https://www.v8buick.com/index.php?t...des-thanks-for-having-me.376007/#post-3294675 And my parts look identical; the baseplate without bypass. On your own forum you have a thread where you show some problems people have with remanufactured carbs, so I took that as a guide to review my own. And that made me think mine was salvageable. So these are my current settings: Idle tubes: .035 DCR: .051 Bypass air: none. Low idle: .083 Upper idle: .052 Main air body: .055 Main air horn: 0.43 Jets: .070 Rods: 44B Secondary rods: AY. I took it for a spin today and I still need some adjustment. Idling and part throttle are performing ok, but when I press the pedal deeper it holds back. I do see that the manual prescribes .045, so perhaps my 44B is wrong? But I'm not experienced yet to tell if that has to do with the secondary system, or the primary or perhaps something else. I'll have to learn more. In case I need parts, like jets or rods, I'll buy them from you.
Is it lacking at heavy throttle on the primary side only, of when the secondaries are in? All of the "B" series primary rods used in that model have .026" tips so it wouldn't matter which one was being used for heavy/WOT scenarios as metering past any particular jet size is the same....
Saga continues. Had it running well 2 days ago (except for the deeper pressing pedal part), drove it hot, adjusted idle mixture screws with vacuum gauge (and a tad bit leaner) Parked it in the garage. Was curious yesterday if it would start after the adjustments, so I tried and yes it did with the choke. Shut it off immediately, because I couldn't take it for a spin. In the mean time made some adjustments to the secondary system; hanger wasn't even, slight adjustment in throttle valve linkage and the air valve wasn't enough spring loaded. So I was confident I had it all ready. These changes shouldn't affect idling/ starting. Today I wanted to take it out again and stranded after 100 yards. Started on the choke, tapped throttle right away so it was on high idle and it was running little rough, but I figured that would go away when driving hot. Nope. First turn and it dies on me on the street. I was able to let it run a couple of times for a few seconds, but only on the "fast idle" setting, so with the choke door a little open, instead of closed. Died everytime when opening throttle. With the choke unloader it would fire a couple of times, on the choke it wouldn't. So I think it was flooding. Eventually neighbors helped me push it back. Took the carb off and gravity tested it with fuel for a couple of hours (no leak) and in the meantime let everything evaporate in the plenum. Changed some choke settings this evening, tried again; dry plenum, empty carb. So it wasn't flooded. But no. Have spark because it's firing, sounding like it's almost there. But no start. Even tested spark with tester, spark is good. Ignition is 8* initial and manifold vacuum. Now is plenum wet again, as are plugs. Have it now at WOT with a string to let everything evaporate once more. Battery dead and I'm stumped. Really didn't expect this. Not sure what to do now. Try the same thing tomorrow and expect another outcome? (Lol Einstein). Try it without choke?
Take the remanufactured carb to a paperweight factory, or melt it down for a teapot....do anything except put it back on an engine and expect proper operation. All those units can do is pass emissions tests. What is the old carb you're using? Seems like it has its own set of unique issues which will prevent any proper engine tuning. Once things get hot & vibrating, conditions can change rapidly. Are those photos you posted of the old carb? Did you install new idle tubes? I don't see any idle tubes installed in the casting in that photo. If your primary throttle shaft is rattling in the throttle body bores, you have a permanent vacuum leak which can never get tuned out. If your mounting bolts/screws were over-tightened, your air horn could be warped which will introduce even more vacuum leaks.
No, not gonna ditch it. It idled like this last Sunday: https://www.youtube.com/shorts/MZYHw1PA7gE Few days later won't start and if it does it runs for a couple of seconds only. That makes no sense. But if it could run like this, it should be able to do so again. And I'm stubborn So I took it apart, again.. Before I started I cleaned out the tub I use to work on the carb and during disassembly I found this in it: It's a piece of tin I used to try to resize the main air bleed a while back. The tin didn't stick for some reason, so eventually I figured I would leave it at .055. Perhaps I pushed it through and it fell in the main fuel well. I didn't actually see it fall out, but if the main fuel well would be clogged with this, that might explain the issues. Perhaps it was not blocking first and due to trembling and heating/cooling and starting again it fell in the wrong position. I tested the well plugs with soap and water for leaks, but they are leak free. Gaskets looked nice, all orifices are open. Put it back together and tried to start it twice shortly. Didn't catch, but it was also 10PM so I called it a day. On the other hand, perhaps the tin fell out of a tissue in the tub and has it nothing to do with it.
The carb is great!! I finally resolved my ignition problems (faulty condenser). The engine runs excellent now. Starts right up, hot and cold, idles well, part throttle is good and full throttle is fun Thanks Cliff!
Good news. Couple of things to remember here. At least 80 percent of the "carburetor issues" I find on vehicles brought here for custom tuning and to get them running correctly are DISTRIBUTOR problems. For some reason I'll NEVER understand Buick and Olds owners more than any others are trying to get ALL the timing in right off idle. I've removed more of those POS aftermarket spring/weight kits from those distributors and hooked the vacuum advance back up than I can count. I've also ran into a LOT of defective Pertronix points replacement modules and had to put points back in the early distributors. A few things for the readers to keep in mind if you are having issues with your "carburetor" and no matter how hard you attack it your problems persist. There are also many ways to reduce or resize air bleeds, DCR's, etc on those "hacked" up remanned carbs or where some "expert" got the drill bits out decades ago and opened things up that should have been left alone. The best way is to tap them for brass set screws and drill them in place. Melting tin, lead or solder, or trying to use epoxy, brass tubing, etc can be lessons in humility......FWIW.......
