Hello. Im new to the site. My name is Chris and I live in central, wi. Ive been an olds fan for years but I found a solid 69 buick riviera two days ago with the original 430 in it. I want to put a new carb on her but I dont know which one to go with. Holley, edelbrock or a q-jet. I know zilch about which carbs are easier to tune ect. So what would you do?
What carb does it have now? The correct carb (as in factory original) is a Rochester Quadrajet number 7029241. However, if having the correct model number is not a requirement for you, any 69 Buick Qjet carb will work beautifully. The stock choke works well and driveabvility is excellent. If it needs rebuilding, there are several top-notch people on this board that can do a great job. Rebuilding costs in the $200-$300 range. I don't have much experience with other brands because the stock carb works best in a normal application.
Hey austingta. It does have the stock q-jet on it now. I rebuilt it yesterday but Im still getting some hesitation off the line. Its not the timing, dwell, choke, vacuum lines, fuel pressure or lack of vacuum. Everything checks out. I have the money to spend so I figure Id put an edelbrock or holley on it. I just dont know which brand or setup to go with. Maybe the edelbrock performer manifold with edelbrock carb?
The fact that it's a Quadrajet is NOT the problem. An off idle hesitation could be accelerator pump in the carb, but if that's new I would guess it's timing. Where is your timing set, and what advance curve do you have? How many inches of hg does it pull at idle? Is your vacuum advance working properly? How do you know it's not a weak fuel pump? They are cheap and easy to replace. Since the car is new to you, I recommend you replace the plugs, points and condensor, cap, rotor, wires, fuel filter, and fuel pump right off the bat. How old is the gasoline in the tank? Those 430's are great motors, but old cars need tune-ups way more than new ones do...
Hi, guys, Hesitation is most often caused by these three things. accelerator pump not working / not working right. Secondary butterflies coming in too soon. [called bog] ign. timing being off. With a stock qjet carb most often the secondary spring needs to be tightened to prevent them from opening too quick. now, that said given the choice, I would go with the Holley spreadbore in 800 cfm with vac secondaries if possible. You can do more in the long run with it, get more accessories and parts for it. Stuff is available in any auto supply / speed shop in town. Books are available and mods are easy all for a reasonable price.
Austin, the timing is set properly. It does jump around some which leads me to believe the timing chain is sloppy? (or something else im not aware of?) When the timing light is on the car (vacuum adv. line disc. and plugged) it jumps around about 2 degrees in either direction. I dont know what advance curve it has. Please describe further. When at idle my vacuum guage shows 19 in. of hg. The fuel pump is brand new. Everything else is new on the car. Points, condensor, wires, plugs, cap, rotor and fuel pump. It only hesitates from a dead stop. When rolling down the highway and I give her the beans its fine. This thing moves. Its only from a deadstop I have problems. At a deadstop and I floor it it backfires through the carb and dies.
My carb rebuild sheet shows the acc. pump rod in the outer position. Is worse when I put it there. Doc, how do I tighten the sec. springs?
On the left side of the upper air horn assembly as you are facing the car, there is a small screw that is just above the top end of the choke rod. turn that screw clock wise to tighten and ccw to loosen the spring tension. clock wise makes the secondaries come in later, ccw makes them come in earlier. how ever from your later post I think that the accelerator pump shot is your problem. it most likely is not enough. set it to the richest setting and see what happens. Sometimes the pump doesnt work ''right'' and it pumps only a little shot of gas. You need a strong , prolonged shot to cover the sudden throttle opening or there will be a sudden ''lean out'' accompanied with a lean out backfire which you are saying is happening.
My stock '69 Riviera came with a Carter AFB 4 barrel?!? That is also what it showed in my chassis manual as the stock carb. I think a Rochester would be aftermarket for the 430 in '69. My car was a standard Riviera, not a GS, I have since long sold the car. Once rebuilt and tuned, it was a great carb.
All stock 430 engines, any year, had Rochester Q-jets ! Carter manufactured Q-jets for Rochester, and they have different part no.s, but are identical to Rochester carbs. :TU:
Thanks for the help everyone. :TU: I readjusted everything today and it launches 90% better. It doesnt stall now. Doc, I dont see that adj. screw your talking about.
