Quadrajet Rebuilder

[48bill]

I am looking for a quality rebuilder for my quadrajet carburetors.  One on the 425 cid Caddilac in my 48 F-1 and the other on my 350 cid Chevrolet in my 48 Chev convertible.  I do not need the replating the restorers want.  I am interested in a quality rebuild for the daily driven F-1/Caddy and the frequently used convertible.

Thanks for the help.

[enjenjo]

It would probably be best to find a local rebuilder that is trusted by the shops in the area. I use a local guy that treats me fair, and was recommended by a couple local repair shops.

[48bill]

Frank,
I tried that and he did not work out.  Apparently he has gotten too old or whatever and is now careless.  Seems to be all the folks I talk with tell me to buy a Holley or an Edlebrock.

[enjenjo]

Frank,
I tried that and he did not work out.  Apparently he has gotten too old or whatever and is now careless.  Seems to be all the folks I talk with tell me to buy a Holley or an Edlebrock.

Well, if you Google vintage carburetor rebuilding, you can find several, but I don't know about any of them. But for the price they get, a new Edelbrock looks pretty good, and is pretty much plug and play. I had a 425 Caddy here  that I installed an Edelbrock 1806 on, and outside of fiddling with the electric choke, it worked fine right out of the box.

[Beck]

I have a guy local to me that plays with the Q-jets. I have only used 1 but he did that for me. It worked super. It deffinately was not cheap. This is not his profession, but is his passion. Every one he builds goes onto his car and is test driven before he lets it leave. I dont know how well that works out since his car is a 6 cyl Firebird and the customers is something bigger normally. Mine went onto a 305 so it wasn't such a big step up as your 425 would be.
He was doing about one a month, but that was a few years ago. There isn't much demand any more.
If you would like I can talk to him to check pricing. Shipping could be direct to him or through me, your choice.

[wayne petty]

what about fortys

https://plus.google.com/+FortysCarburetorandAutoRepairEastLongmeadow/about?hl=en&gl=us

its too far to ship them across the country to me.. and i don't have a mule motor to test and adjust them on..

there are some serious secrets with quadrajets.

polishing the accelerator pump bores with a piece of fuel hose and a slit with 600 sand paper..
redoing the seat in the accelerator pump check ball cavity... is as easy as rotating a phillips screwdriver in the hole to burning the seat.. then using the OLD check ball and a pin punch and a small hammer to create a ball shaped seat..  warning this divots the check ball..  so you have to use an old one that you have a matching replacement for..

please..  DO NOT adjust the APT screw.. if its a factory built carb..  if its been tampered with.. well. this is done when the carb is done and installed..

it can be done in a small parking lot even.. as long as you have GOOD traction..  do you know what a dry hop is.. that's what i always called it..
where you give it moderate acceleration for a split second.. to see if it bogs.. or falls on its face..  you start with the tool down the proper hole to feel the primary metering rod holder..   the APT adjustment is the DOWNWARD limit the vacuum can pull the rods into the primary jets.. this is the point where it comes INTO the upper end of  idle transition and starts flowing on the mains.. if the metering rods are too deep.. it will be LEAN as it begins flowing..  if they are TOO HIGH.. it will go rich and fall on its face.. but also wipe out your fuel economy..  get it perfect.. you will LOVE your carb..   i did this with the QJ on the tire shop owners 70 GMC.. with a 75/76 carb..  he punched it and it spit and bogged..  i turned it a quarter turn up..  he tried it again.. still spitting.. another quarter turn.. finally it got better.. soon he was SMILING.. when it started to fall on its face.. i went the other way..  he was very impressed..




the early APT adjustments are HARD TO CHANGE. part B actually sticks up above the base plate surface.. the pin on the bottom of part C sticks out the bottom of the float bowl and thru the main body to throttle plate gasket.







the secondary air door is tuned the same way... or follow the settings as a baseline from the build paper..




there are a bunch of other specific to the model things to do..

list the carb numbers off the drivers side of the carb..  70xxxxxxx or 170XXXXX  these are STAMPED into the side of the main body.. NOT cast in..  and some pictures..

[wayne petty]

these are best left alone.. but if you have one thats been screwed with..






this is the LATER 1975 up APT adjustment.. please.. DON'T move this.. it does not have to come apart to be cleaned.. it will require seat of the pants or an air fuel ratio display and an oxygen sensor to adjust properly..

the APT adjustment is a DOUBLE D shaped  screw head down the bore below this tool that is really the WRONG shape for a proper adjustment..

[wayne petty]

75 up quadrajet APT adjustment.



somebody replaced the APT screw with a phillips head screw..




at idle... note the primary rod hanger is down and the needle deep into the main jet..




this is at cruise or when first coming off idle.. note the rod holder is still seated by manifold vacuum..





this is with the throttle at wide open.. under LOAD.. both primaries and secondaries flowing...
note the primary rod holder is up and the metering rods are not as deep into the primary main jets allowing more fuel.




oh... and the hardest thing on a quadrajet.. getting the lever lined up..

let it hang..  stick the choke thermostat shaft thru the hole.. its a tapered shaft.. use the rod to rotate the lever 90 degrees to align the double DDs on the lever with the shaft..  reduces 2 hours to seconds..




on some early quadrajets.. there are thin brass cups pressed into the cover see red circles.. do not blow these out with compressed air.. you will have a flat spot you can never get rid of..

[Beck]

This sounds like a road trip from CT to CA to me...

If the carb will fit in a flat rate USPS box shipping wouldn't be too bad. Same price to Wayne as it would be to me.

Even UPS wouldn't be terrable. A Q-jet isn't that big or heavy.

[tomslik]

wayne, you forgot the most important problem with a q-jet.

the morons that think it's gonna fall off the engine so they tighten the snot out of the mounting bolts, warping the airhorn.

[wayne petty]

that would take shipping to another fellow on the east coast..   he had a warped quadrajet.. so since the straightening tools are no longer available .. he made a set of them.. out of some 3/4 inch plate.. the new gaskets as templates.. and a drill press..  i have a nice steel fab shop i can probably get some plate cut..  but my Friend left the drill press i had.. out in the rain..  he did not realize that it was not water proof..  he did hose the dirt off it once in a while also.. i just stood there and cried quietly to myself.
i had only drilled about a dozen holes with it when he needed it for a job..


i also DON'T have a test mule motor to run them on to get the adjustments even close..  i don't even have a shop to work in right now.. just a 5 gallon bucket of tools..


i will be glad to skype with you.. if you have a high speed internet connection.. or assist you thru the web.. even phone calls..

i could use the actual part numbers off the sides.. so i could get the proper info to send to you..  there are slight variations between years..

quadrajets really are simple carbs if you understand them..

and yes.. that is a TACK hammer.  i love it.. use it all the time..  not heavy enough to smash fingers..

[UGLY OLDS]

Gee Wayne .....Your tool box looks just like Frank's bench .....
( And mine too.....   )



Bob....

[enjenjo]

Gee Wayne .....Your tool box looks just like Frank's bench .....
( And mine too.....   )



Bob....

I think I see a few of my missing tools in there

[wayne petty]

oh... the quadrajet straightening plates that i don't have a set of..








the big squeeze




and the from years and years ago..



i hope to impress nobody with that stack of junk cheep tools..

my tool box full of snap on and mac tools got stolen in 1985 and i never replaced them.

i was even thinking of taking four 5/16-18 coupling nuts..  bolting them to the bottom of a carb.. and welding them to a piece of sheet metal as a carb stand..

[tomslik]

nice fixture, didn't know they made anything for that....

I just walk over to the press with the airhorn and a straightedge....and be trally friggen careful!