Don't buy a remanufactured Quadrajet. Those big companies can make a mess.

Discussion in 'The Venerable Q-Jet' started by carmantx, Sep 22, 2013.

  1. carmantx

    carmantx Never Surrender

    You hear it all the time, somebody buying a quadrajet from the parts store, online or wherever, and the part number says it will work on your Buick. Many good rebuilders won't even touch these things because there can be too many issues to deal with to try to correct.

    So I thought I would start a post with some examples. There are many good quadrajet builders on this board, so I hope to keep some people running them, and not bailing out for an Eddy or Holley. Sure, they work too, but point here is the mess the big reman shops make of the poor quadrajet.

    I bought this 7042940 800 cfm cheap, because the seller said it would never idle on his car. Looked nice and clean when I got it, so I couldn't wait to see what was wrong.

    Some instant notices, wrong baseplate and vacuum ports, but it does have a correct throttle arm. Air horn is wrong also and has a few extra holes.

    Inside, and the reason it won't idle.

    Idle tubes are pressed in on top, not original collar system. These are .055 and should be .032
    Idle restrictions are .061 and should be about .058
    Upper idle was .070. Should be .053
    Lower idle was .083. Should be .078
    Upper main was .046. Should be .070
    Lower main was .046. Should be .040
    Had 70 jets, should have been 73

    Not to bore you with a lot of numbers, but the factory spec were set up to run for specific model it was designed for, a Buick 455.

    I have also seen the fuel seat pressed in on some remans so the main body is ruined beyond repair.

    Post any other horror stories you may have seen.

    And don't let your friends buy big store remans. Let one of us build one for you!
     

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  2. WV-MADMAN

    WV-MADMAN Well-Known Member

    First off, Im a Holley guy.

    Just for the record.

    Im no carb guru and if a carb needs major surgery Im not your guy, but Ive built piles of Q-jets over the years and your right, the parts-store Q-Jets are beyond junk.

    They are part of what turned me against Q-Jets:rant:

    When I was a GM dealer Tech, guys would come to the dealership with carb troubles...

    Do the math on how old a dealer Tech would have to be to have worked on carbs:puzzled:

    As a hotrodder I am pretty good at old school tech so I would rebuild carbs/set timing/ect on the side.

    About 7 out of 10 Q-Jets that came my way were re-man garbage and they turned their correct Q-jets in as cores:Dou:

    Holleys and Eddies, I could have out the door in a couple hours with happy customers.

    Thanks to the re-man Q-jet plague, I was stuck with three times the labor, 5X the parts and a 50-50 shot that the customer would be happy with what I gave back:rant:

    And the problem of good cores is getting worse every year...

    To the Q-jet faithful, Once more into the breach dear friends!!!:pray:

    But for me, Im out.
     
  3. carmantx

    carmantx Never Surrender

    Haha, I built quadrajets at my first mechanic job. Tech wasn't even a term then at the dealership.

    Good cores are getting harder to find.
    I bought this for parts, and I am going to modify it for my 462.

    Quadrajets still have a place out there. I am saving all I can.
     
  4. WV-MADMAN

    WV-MADMAN Well-Known Member

    Ahh, the good old days...

    I thought the term Tech was silly when I started, until I realized that I spent far more time with a computer in my hands than I did a wrench:eek2:

    Nowadays ''Technician'' fits the job description better than ''mechanic'':rolleyes:

    But now I work at a Ford dealership...So now I guess Im a Cobbler:laugh:

    Keep on keep'n on:TU:
     
  5. robs71redriv

    robs71redriv robs71redriv

    lots of info on the subject in the Buick libraries
    http://buick-libraries.boattail-riviera-by-buick.com/

    You also have to be very careful when buying rebuilds kits -the June issue of the Rivin it Update, In the Headlights was all just that - with decode and individual part numbers for 71-73 4Mv Qjets
    - any one who wants a comp copy just PM me an email to send it to[​IMG]
    2013 06 Jun - Rivin It U-date Boattail Registry

    Heres an extract of some it



    Mixing parts from various year and model carbs doesnt work read the Tuning by Lars - Qjet & Engine
    Tuning Manual article in the library to see all kinds of problems and fixes caused by improper
    rebuilds. Its the main reason the Qjet gets a bad rap from those who dont take time to do it right
    (inc many of the professional rebuilders out there.)
    Login to libraries and click picture to goto
    Often times the carb is not even the problem its the people who messed with them, many problems
    blamed for poor carb performance are basic maintenance things like vacuum leaks in vacuum hoses
    lossed carb screws carb base gasket/or loose hold down bolts sticky or leaking diaphragms
    choke and other adjustments
    - intake-manifold leaks timing plugs wires dist points etc should be checked before
    replacing or rebuilding your Qjet they will cost you less to correct and if not addressed still
    be there when you install your fresh carb.


    Rebuild kits are more often for 750 cfm or 350 QJet and SBC speced they have wrong parts for your
    800 cfm 455 Buick Qjet, so be careful when getting one check all the parts with these charts.
    If you got the kit from aftermarket places like Holley its almost certain to have been developed
    for a SBC send it back or throw it away its you might as well bolt one of their carbs your Riv
    will idle /run just as poor with one those kits installed.


    With the proper "companion" parts. Internal parts such as jets and metering rods, air horns etc the
    Qjet is probably the best overall street performance carb you can get. By insuring they remain
    intact with the intended parts you retain original flow characteristics matched to your engine
    (like the sticker on the air cleaner says Keeping your GM all GM here is important for the smooth
    performance and the best fuel economy.
    The following charts give individual part numbers for each model carb
    Great for the person who wants scrounge parts, or verify they got the right ones to do right
    You can find lots of individual parts and overall kits at
    http://quadrajetparts.com/rochester-quadrajet-parts-c-128.html
    Most are cross referenced to OEM part number in the part book charts below



    If you dont wish to tackle the rebuild job heres a Member Recommend Rebuilder (one of the palces that seem to do it right )
    Autoline Carburetors
    http://www.autoline.ca/carburetors.htm
    Their remanufactured Qjet carbs are sold thru Rockauto and are working great on the member Rivs
    they have already been installed in unlike the Holley and Edebrocks in some others.


    The other model/year Buick carbs parts lists - 65 thru 75 and detailed information on servicing
    /adjusting your Qjet is available in the various pubs in the ALL Buick Model library . more
    Rochester Carb info is in the works. (we have around 20 pubs manuals and bulletins sent by library
    member Sean Smith that cover carb applications and adjustments for most GM cars and trucks from
    1932 thru 1980, just ask if need some info in the mean time and Ill
    be glad to dig it out for you) and of course the various chassis manuals have carb info too.





    http://fullsizebuickregistries.boattail-riviera-by-buick.com/Library/Common/1960s-70s/documents/index.php?model=%27.$modellibrary.%27




    [​IMG]
    Tuning by Lars - Qjet & Engine Tuning Manual Lars Grimsrud sent in by Lars - this includes how to it right and common things done wrong







    libraries memebers can get the same info for 65-76






    [​IMG]
    1965-76 Parts Cat Carb Dia & Parts - GM Corp - sent in by Dana Laiche - shows diagrams and full part numbers
     
  6. Cliff R

    Cliff R Well-Known Member

    I could EASILY write 3-4 full pages covering the issues we see with currently available commercially "remanufactured" carburetors. They are nothing but JUNK, and should be avoided. We don't even want them sent here, and in most cases will not work on them. A guy is better off spending the time/funds on a grungy original unit, as it will ALWAYS deliver a better end result. The biggest reason folks get poor results rebuilding their original units is that they use poor quality and incorrect components. NOTHING over the counter is going to be up to par for todays fuel, and the needle/seat assemblies will always be the smaller generic version, not the good factory high flow Viton tipped variety. Your DONE if you buy a NAPA or Pep Boys rebuild kit and think that you are going to get a good end result. Don't be fooled by the "blue" seal on the pumps, they are "soft" material and will swell up and fail in contact with this new fuel. I see this every single day, and why we install our own seals on the pumps that we buy from the suppliers. Bottom line here, and when it comes to this topic, IF your rebuilt q-jet doesn't perform flawlessly in all areas, and work better everyplace than an aftermarket "high performance" carburetor, you screwed up someplace with the rebuild and/or recalibration. http://www.youtube.com/watch?v=6zVdoLR-VzM http://www.youtube.com/watch?v=exivLgmaBc0 The first clip is my car in hot/humid August weather at Norwalk, with the timing retarded 4 degrees and shifting at 5000rpm's to stay roll bar legal. The second clip is a Buick 750cfm carb in action, sent it to the customer and got him solidly into the 10's on his first outing. Yes, we didn't even use the big "800" cfm Buick casting, it would have been too much for him to deal with all at once! Seriously, these are not Q-jets that have been "modified" in any way when it comes to a sanding roll or grinder, they are completely "stock" castings, simply recalibrated EXACTLY for the application. If you think you have to spend your money at Summit or Jegs to get your V-8 Buick into the 11's, or even quicker, your throwing spending money in the wrong places. Buick Q-jets are EXCELLENT units, they just need a few good parts, and a tweak here and there, and the end result will run right with, and in most cases outrun anything else you can find to feed your engine........FWIW......Cliff PS: pic of the pumps we use with the "soft" blue or black seals being replaced....
     

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  7. techg8

    techg8 The BS GS

    Throttle plates with holes when there should be none

    Throttle blades without holes when there should be some

    plugged up Idle air bypass leading to nozzle drip or Idling on the mains

    plugged upper idle air bleed causing the fuel bowl to siphon out after shutdown

    mismatched base/bowl/horn which screws up the bleed sizing etc
     
  8. carmantx

    carmantx Never Surrender

    Good points.

    Cliff, you are so right on the "over the counter" kits and junk parts in the cheap kits. And you know where I get all of mine! Thank you for keeping good parts available.
     
  9. gsgnnut

    gsgnnut Well-Known Member

    havent ever bought a reman q jet, I always rebuilt original ones that had not been messed with, but 40 plus year old carb castings eventually wear out and repair possibilities are limited. I went to an eddie myself, and it has worked flawlessly for the last 10 years. No thanks, you racers/restorers can have them. i have a collection of original functional Buick q-jets that Im holding onto just in case i bump my head or change my mind or if they become stupid valuable, but for now Ill stick to newer technology. :grin:
     
  10. TimR

    TimR Nutcase at large

    We've been very lucky up here in Canada all our premium fuel is still ethanol free (Shell V-power and Petro-Can Premium), so the standard kits have worked for me with upgraded seats/needles (bought online a while back, larger and good quality). No issues. I recently ordered some base gaskets and various small parts from Mr Ruggles an I have to say I am very happy with them all. Excellent stuff. There is now talk of ethanol being blended in our fuel too >>sigh<< so I know where the rest of my parts will be coming from! Also I support the guys who support us, the tips and tricks and knowledge he passes on have helped a lot.

    I see the carbs on rockauto by autoline, not even worth it as a core? Old Q-jets are impossible to find up here (esp Buick...)...I like to keep my cars more or less stock looking, so a q-jet is a must for me. Set up right they do work very well, tuning can give a guy fits some times though.... :)
     
  11. Cliff R

    Cliff R Well-Known Member

    Here is a note from a recent customer who bought a "commercially remanufactured" carburetor for his Grand Prix. It was from Holley (among the worst of the companies that do this, IMHO). He sent the carb to a carburetor shop because it didn't work correctly. He was trying his best to save the carb, as it sported the correct number for his restoration. After several attempts to get it rebuilt and working correctly, with no improvement, he asked us to take a look at it. I decided to scrap the "butchered" up center section, and substituted a 7044244 Buick casting for it instead. The original "remanufactured" casting was complete JUNK, even having a POS pressed in double "O" ring fuel inlet seat, and they "O" rings got cut during the install and were hanging out around the seat. Anyhow, here's a note from him after he got the carb back from us: Cliff:

    I received the carburetor today and installed it on my 70 GP. I of course took it right out for a road test. What a fantastic difference. There is no more flat spot. It accelerated smoothly through the gears without even the slightest hiccup. After almost two years of messing with this issue, YOU HAVE FINALLY SOLVED MY PROBLEM. Thank you for your expertise. I appreciate all of your communication and your effort at getting it right. When and if I find a 7040564, I will be sure to contact you to let me know when I can send it to you for a rebuild. That would put me back with matching numbers again. In the mean time, I am a VERY VERY HAPPY CAMPER. You will receive honorable mention in my GP club, although I think many in the club already know your good reputation. In my opinion, you are truly a master at your trade. Incidentally, much to my surprise, the Florida rebuilder sent a refund to my credit card. I'm sure your input helped tremendously.

    Highest regards,

    XXX XXXXXXX
     
  12. carmantx

    carmantx Never Surrender

    I pulled these idle tubes yesterday, one clogged. Quadrajet wouldn't idle right after a kit installed by a local shop. Spraying cleaner on outside and new gaskets won't fix this.
     

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