Yep it's me again, the new'be. I have been reading all these posts about the "Bog" of the Q-Jet when the second dairies open. I (Stock 1969 350) know my carb needs rebuilding because it is still a virgin. I dont get any kind of surge when I am rolling and stomp it to the floor? I know the carb is opening all 4 but how do I know if they are opening wide? My 67 olds 330-4 when you open it with out an air cleaner it sucks in birds,tree's and 2 x 4's into it? My GS even with the ram air cleaner off does not get that 4 barrel howl? The car runs great! If I stomp it from a dead stop it does not hesatate and spins the tires all most untill it shifts into second (auto trans, 342 gears). Note: if I am under the hood and hold open the top rear top butterfly - choke cover what ever it's called and snap the throttle open it defenitly has a bog and the 4 barrel sound to it. Every thing on the carb linkage wise works and both the vacuum modules are new and work. It just seems like the carb only opens 3/4 under full throttle? I have seen the posts about to much bog and setups. I know a person that can rebuild this carb for me but I want to give him as much info as I can. PS: I just want it to be right! When I spoke of spinning the tires they are 225 70's I put on in 1999 with 30,000 miles on them. I try not to beat this car. Thanks again............. Mark
Right, it sounds like you are not getting that great sucking sound from your secondaries- Long ago I had a 68 LeSabre, it had the sound! So you are looking at the right things- make sure the choke is working properly! I had Carmen Faso rebuild my Q-jet for the WaGone, Best Thing That I've Done! Carmen is near Buffalo, NY 716-693-4090 Ted :beer
Thanks again Ted and like I said in the message to you this guy is Mr Buick in the Buffalo, Tonawanda area. Best of all he has a VERY Large stock of NOS GM parts for under the hood. Thanks for all the replys I can see this is not like the boards my kids go to!! Mark
If you are getting a good tire-spinning launch with no bog I really don't think there is anything wrong with your carb. You can try loosenning the secondary butterfly spring until you DO get a bog, then tighten it back up a hair. If you have a vacuum pump (Mitey-Vac) you can hook it up to the front vacuum break and see how long it takes to extend when you dump the vacuum. Shouldn't be any more than a second. There is a tiny pin hole orifice in the inlet tube of the vacuum break, which can be drilled larger to get the vacuum to dump quicker, but if you get it too big then you will bog and have to get a new vacuum diaphram and drill it out less. Sounds like you are happy with a dead stop launch, but not when punching it from a roll? Is your transmission kickdown functioning? It may simply not be downshifting, keeping the revs from coming up. The Q-jet is designed so that it only uses as much secondary as it needs. You cant "make" it open all the way if it doesn't need the flow.
As for the car running great it does! And the trans works perfect. For sure all 4 barrels are opening to some point because if I roll into the gas you can feel when the secondary's open. As I said on another post if I am under the hood and hold the choke-top? of the secondairy's open and slam the gas open it sounds like my old trooper car with the aircleaner flipped! I also had a 67 olds 330-4 and if you took off the air cleaner man it would suck the hood in. My GS even with the air cleaner (ram air setup) off the car it just never gets that 4 barrel howl?!? People in the Buffalo, Tonawanda area know Carm Faso. He looked my car over last year after it was tuned to find one of the two carb vacuum units were bad, new points bad and a couple of other things (I thought it was great NAPA had all this stuff!). I plan on having him rebuild this carb and install his HEI in the distributor Thanks again for input. Mark
The Q-jet secondaries will usually not open when you rev the car in park or neutral. By this, I mean that the top air valve will not open. It is vacumn actuated, and with no load on the engine it is difficult to make it respond. So, naturally, if you are holding the valve open yourself when under the hood you will hear the sound, when otherwise you wouldn't. To verify that the secondaries are opening all the way, you need to check the throttle valves. Do this by opening the air valve with the engine off. Look down the throttle bore and have someone push the gas pedal to the floor. The throttle blades should be straight up vertical. If not they are not opening all the way. You need to do this with the choke all the way off, because there is a lock out on the Q-jet connected to the choke that will prevent the secondaries from opening if the choke is on. ( BYW, this could also be causing your problem). If the throttle valve is opening all the way, it is possible that the air valve isn't. To fix this you can try adjusting the spring that controls the tension on the air valve.
I again thank you for your input. And anyone else that has 2 cents I will listen. I do understand what you and others are talking about. It just feels like the surge I am used to from my other 4 barrel cars is not there? When I say there is no bog or howl when it is floored I meen this this car all most seems like it has a 2 barrel on it when you hit it? Again rolling into the gas it most definitly has secondarys opening but "again" that surge, bog, "Howl" sound is not there. Other then a "sound" problem the car is out standing! Mark
If the sound is the only problem, it is possible that the air cleaner itself is restricting the airflow. Some of these units were designed to control the sound, restricting the airflow as a result. The Centurion, "Deuce" and the Park Avenue are examples. The air cleaners worked, but the sound was gone, due to restriction. This may also explain the perceived "response" concern. Food for thought. Ray
I'll second what Ray said, the Buicks were designed to be quiet. I've noticed a difference in sound when switching air filters. Some are a little bit taller than others, and because I have a lid from an earlier car on my aircleaner, the lid doesn't seal totally with all brands of filters. When it doesn't, I hear a noticable sucking sound. When it does, the sucking sound goes away.
did u try taking off the aircleaner and flooring it? i didnt hear much of the carb when i had the factory air cleaner on. I can sure hear it now with the edelbrock air cleaner lol.
Guys its not a sound problem. I am running the stock ram-air unit with the vacuum doors all ways open to the hood openings! I am running the round K&N replacment filter. Even with this whole air box off the car I just dont get the Q-Jet drone or howl or surge what ever you want to call it. I am having it rebuilt and will adress all the carb info I have received from my posts. Mark
