anyone running a Quadjet

[1958]

I ran these back in the day and they where good carbs and if I remember they did pretty good on gas because of the front barrels where smaller I am thinking of running this on my sons truck found a intake and carb for $20. So I guess what I'm asking is what do yall think about running this set up,Thanks


Chris,

[1project2many]

Hello

I've always preferred properly adjusted Q-jets over Holleys or AFB / Edelbrocks for street and even some mild performance use. These days tuning them for lean cruise, rich acceleration, and snappy secondary operation can take time, work, and a box of parts scrounged form other carbs. I don't know what intake you're using but some are good and some are poor so do some homework there.

The only vehicle I have left that's using a carburetor is my '36 Plymouth. My '57 went to EFI in '92 or '93.

[1958]

I gotcha dude my 73 Z-28 had one and it was bad when those big barrels kicked in I have a factory intake with matching carb.

Chris,

[jackson]

that's what im gonna run on my 283. good gas milage if you keep your foot out of the secondaries

[Hubscrub]

yes, i run them and like them, just yesterday i was driving my wife's 67 and kicked it down,(has an 1406 edelbrock on it) and was thinking boy that don't sound like a q-jet when it kicks in that vrooooooooom. I bought the book from cliff r. on them to get more understanding of them. Great carbs.

[geezer#99]

What motor?
What tranny?
Carb will work but intake might cause a problem if you need an oil fill tube.

[1958Warrior]

I've got one I'm going to try out when I get the truck running, it was remanufactured by Edelbrock, Summit used to sell them $450, I don't see the on their web site anymore.
They carry some Jet brand ones.
I had one on a 76 Monte Carlo the (BIG ONE) back in the 80's that I borrowed of am old wrecker with a 454 in it , that with a performer intake and cam kit combo they used to sell, on my 350 . I was out running Camaros and Novas back then.
It did have a distinctive howl to it when I stomped on it ...ALL the time.

I would go through it ,look for pitted seats and needles, and worn linkage,
all can be bought very reasonably.

[Speedbumpauto]

Linkage, etc. can be bought reasonably but what wears out, because they were pretty good, is the throttle shafts and base plates. Most or many of these old carbs are just flat worn out. The cores are bought up by a rebuilder who puts a kit and a float in them and sells them as reman. Almost none do anything about the shaft wear problem because if they do, the price would go up dramatically. If you can find them new, the price is comparable with Edelbrock, Carter, etc. but the access to tuning parts is less than optimum....because they're not as popular anymore. The Carter/Edelbrock style has almost the same mileage potential as the Q jet and I wouldn't consider getting into an old Q jet unless it was a numbers matching kind of build and as a "cut em up" kind of guy, I stay away from that kind of thing.

[OrrieG]

I have early non-smog ones on my Chevelle and Truck, both came off running vehicles. Like the small primaries for around town. Used to run Holleys but got tired of always messing with the idle circuits. Would still run Holley on an race engine or one that saw a lot off higher rpm use.

[1project2many]

Almost none do anything about the shaft wear problem because if they do, the price would go up dramatically.

There's really no excuse for letting a "rebuilt" Q-jet go with excess shaft play. It's a fairly simple task to remove the throttle shaft, use a valve guide reamer to open the holes slightly, and install bushings in the shaft to remove excess play. I do not find this additional service dramatically raises the price of rebuilding.

Q-jets suffer from other flaws that can cause problems for a rebuilder. The plugs under the secondary jets and main fuel well can leak which will cause slight overfueling at idle and will primarily cause hard starts due to flooding while the engine is shut off. There are some solutions, some of which last longer than others. The springs on the secondary air door can lose tension or end up improperly adjusted time causing the secondary to open too soon and potentially causing excess fueling while operating on the primaries. OEM secondary needles may be worn out where the needle has repeatedly struck the secondary jet over the years causing excess fueling when the secondaries begin to open. Threads for the fuel inlet nut / filter cover can be damaged or stripped and this might not become apparent until after the carb is installed. Even if there are no hard parts that are damaged, aftermarket rebuilds may be supplied with needles, jets, and hangers which are unmarked, that have the original numbers removed, and that have been modified to add or delete fittings or throttle connections that can make tuning a challenge. Ultimately this means, for me, it's preferable to start with an original carburetor over buying a rebuild.

[Speedbumpauto]

[QUOTE=1project2many;7018856]There's really no excuse for letting a "rebuilt" Q-jet go with excess shaft play. It's a fairly simple task to remove the throttle shaft, use a valve guide reamer to open the holes slightly, and install bushings in the shaft to remove excess play. I do not find this additional service dramatically raises the price of rebuilding.

I have the equipment and have done it on my guide and seat machine with a reamer as described. I find that careful set up to ensure parallel bushings and shafts + the R/R of the throttle blades takes between one and two hours. Even at only $50 per hour, that's an extra $100. I won't do it on Q jets anymore because it doesn't pay. Only on Stromberg, Holley 94's or weird stuff where it can pay to restore them. Agree on the other problems and just don't think it's worth it anymore.

[1project2many]

I won't do it on Q jets anymore because it doesn't pay.

Point taken. I have a little jig I made years ago that I use with a hand reamer. I tap the bushings in by hand and use a dummy shaft to ensure proper fit of the original shaft. Maybe there isn't enough call for Q-jet rebuilds today to even make the jig. In the '80s when OEM carbs with 20k mi were leaking too much air it was worth the effort.

The level of machining you're talking about is more than the average rebuild customer wants to pay for. I'd call it "blueprinting" as the results are better than new.

[T-P Auto]

Hello;

I have run Q-jets for the past 20 years.
I have rebuilt several over the years.
I perfer the Q-jet on a sb350/283 over any after brand.
I get very good mileage n good perfermance.
I try the 2bd to 4bd milage.
The 2bd got 14 to 15 mpg
The Q-jet 4bd got 16 to 18 mpg.
So long as you stay out of the back 2bd.
I seal the secdary well plugs with the old style 2part J-B weld.
Most kit now days just give you gaskets n acc pump only.

I will run Q-jet as long as I can find them n rebuilt them.

T-P Auto
Tim

[DransportGarage]

The definitive manual on Q-jets, as mentioned above, is:

"How to Rebuild and Modify Quadrajet Carburetors" written by Cliff Ruggles, published by Car Tech. Don't bother with the Haynes manual.

[T-P Auto]

Dransport Garage;


You are so right;
Someone who is just starting on Q-jet would be best to have some form of information.
So it would be ideal for him to get the info.

I have run chevy most of my life time so for me to do a Q-jet come easy.
With the way the systems are now day a good carb rebuilt person is getting very hard to find.

T-P Auto
Tim

P/S to 1958 - just take the time to really ck out the carb n intake you have for what you want to use it on n for.

[1project2many]

I found Doug Roe's book to be very helpful when first starting out.

[Apachemike]

If you need a q jet rebuilder pm me. I use Lars out in Colorado. He does q jets for everything. Rebuild and run on test stand so just bolt on when you get it back. Cheaper than Factory type rebuild

[BIGglaSS]

Bushings are cheap. I bought them from McMaster. Build a simple jig, use a 3/8 drill and drill press, or reamer. Off hand, I don't have the part numbers, will post them later. The ruggles book is a must have! Then call cliff for parts. ei needle/seat, rods, etc. Tell him what it is going on, and he will tell you what jets and rods you need.
http://www.cliffshighperformance.com/
The late model QJets don't leak at the well plugs. I can't remember what year they fixed that. Also, late model (77-79 or so) are the larger bore 800 cfm with APT adjustment.

[Russell Ashley]

Originally Posted by Apachemike

If you need a q jet rebuilder pm me. I use Lars out in Colorado. He does q jets for everything. Rebuild and run on test stand so just bolt on when you get it back. Cheaper than Factory type rebuild

You don't need to send a carb to Colorado, there is a great place right here in the Atlanta area. http://www.carbspec.com/

[DransportGarage]

Just a thought...I re-shafted a 12-pack of Holley 94s with +.005" shafts (no bushings required).



I'm wondering if anyone makes oversized shafts for the Q-jet.

[Speedbumpauto]

I used one on the last 94 I did. Pretty slick. Got it from Speedway. Didn't see anything for newer stuff. Probably came to the same conclusion I did.