Author Topic: Remanufactured Carburetors  (Read 5810 times)

Offline Cliff Ruggles

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Remanufactured Carburetors
« on: November 24, 2021, 03:31:28 AM »
I get a LOT of calls to the shop after someone has purchased a "remanufactured" carburetor.  The owner doesn't understand why the "new" carburetor isn't working well.  They say a picture is worth 1000 words so I'll put some pictures up here of one I took apart yesterday. 

This carburetor has not been in service that long but you'll notice heavy rust on the metal parts.  This happens because all the zinc is stripped from them during the rebuilding process.  They also mix/match components.  This carburetor has a 1972 Chevy center section, Cadillac baseplate and Buick top.  The choke parts on the side are 1970-71 Chevy.  It has been "hacked" internal in a lame attempt to make those parts work together but is WAY off the mark as far as being able to work well on anything it would end up on.

For example, the upper IAB's are .099", the lowers have been smashed down smaller and the DCR's are the largest I've ever seen in a Q-jet at .090".  The bypass air is blocked with lead plugs.  The Power Piston hanger arms are bent and spring is missing.  The PP spring is not from or for a Q-jet, it looks more like something you'd find in a ball point pen.  It has multiple other issues as seen in the pictures.......
« Last Edit: November 21, 2023, 05:33:04 AM by Cliff Ruggles »

Offline Cliff Ruggles

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Re: Remanufactured Carburetors
« Reply #1 on: November 24, 2021, 03:33:09 AM »
More pics....

Offline Cliff Ruggles

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Re: Remanufactured Carburetors
« Reply #2 on: November 24, 2021, 03:37:45 AM »
This carburetor was being used on a 1970 454 Chevy LS5 engine with a manual transmission.  It has recently went across the auction block at one of the big auctions and was sold as "numbers matching". 

I guess it ran long enough or they pushed it across the stage so they could complete the sale.  It was put in a trailer and delivered to the new owner and it would not run well enough to even take a test drive and refused to idle or stay running.

Two out of the four main bottom plugs (one front and one rear) are leaking like Niagra Falls as the cheap epoxy they dabbed over them had already failed so it's probably a good thing they didn't continue to use the carb and "wash" the engine.

Folks this is what you are buying no matter where it's sourced out at and many are worse than this one........Cliff

Offline Brian B.

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Re: Remanufactured Carburetors
« Reply #3 on: November 26, 2021, 01:57:52 PM »
It makes you wonder whether the people that manufacture these things are completely inept or just don't give a damn.

Offline Cliff Ruggles

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Re: Remanufactured Carburetors
« Reply #4 on: November 27, 2021, 04:54:03 AM »
In order to sell them one unit has to be able to cover a wide range of applications.  They aren't taking specific part numbers, rebuilding them, and selling them for someone looking for that number.

To meet the needs of potential customers they instead build "generic" units with pretty much the same thing done to every one of them.  They are built from mixed/matched parts, "butchered" up internal and assembled with cheap parts.

Then they sell the end result to cover a broad range of applications.  This carb in particular is something  you would get ordering a replacement carburetors for any 1970-1971 Chevy application that originally used a Q-jet.......

Offline qjetsrule

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Re: Remanufactured Carburetors
« Reply #5 on: December 02, 2021, 08:43:30 PM »
So often you hear, "Put a Holley on it, quadrjets are junk!" This is why qjet get a bad rap. Too bad nobody will recast quadrajets for performance cars.

Offline 73ss

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Re: Remanufactured Carburetors
« Reply #6 on: December 04, 2021, 11:01:51 AM »
So often you hear, "Put a Holley on it, quadrjets are junk!" This is why qjet get a bad rap. Too bad nobody will recast quadrajets for performance cars.

It appears that some outfit on e-bay is. being sold as new, I don't see any rochester markings or part numbers in the pics. They do look like new castings. Who knows what kind of a mess is inside. It looks like they sell quite a few though.

https://www.ebay.com/itm/174854205621?_trkparms=ispr%3D5&hash=item28b61f70b5:g:ZtIAAOSw7iFgCM~C&amdata=enc%3AAQAGAAACcPYe5NmHp%252B2JMhMi7yxGiTJkPrKr5t53CooMSQt2orsSDAeS9EQtjPGVfKXTxF0%252BjupDcO6czu5Fqg%252Bw5Gjp1j0%252F1Bnr1Mm4zyUNyFfwpkcN77lQMDDf9hzixFcU4IHG1tMbTKQzyJdE6YRc1krgloTsLhJFBTz3DUj6zzjbHiYfldRVYPb%252FJja3xHyfCeFPnf54tuqRjTzRADIQ1oqQIHYg7O4JOOoLBl9S7QN%252FHGM787pq1iyTRlO9EoBPwlFPWNZF6zdC1zxt5bd29wVur3oLlt0EYZ0rz8N5jevCfzRrqACTPcGh1kqJDJZRpzlz0XGN4m1fzOMw3XxcmsRBtZLSeiokp3UlmB%252Fc%252Buo7M7n6cPjxHK%252BgrqJTYUCPppTJwlTNb5LXel44qW9nuP4w7Ipkr9FmMIPFOdChcuoo%252BdsbHYcVmHOjnfcek7D97DAkSaOG4q7xXHBDO7%252FnZsJFWTnbC7gmZGqx9NxY9ZAwTXh1y%252FblkeeTyZ7qTE4O6jBilYNSPhFx%252FvbIZ0%252BvCCUV2GtA79a%252B0SyizW%252FeK7Gnwt0cg3CBL7WT2xW5lHbv8uMr8ntFsc0LFHLcm7V4iHGAELRfuPPojz%252BcnD71sCXxaLJpSOcZcWV%252FrzVg%252BTEbEm4WoGKM1Ll2OaeTqvWnRmGIsAEslV%252Fb2Sl2Ss8Y5JZJ6thaPbKd258M2xhfSpUb2uOuCNCOpmASZBQzoPVYrvx7zlxQZYDtEFw%252BiU0Mog5Bdx0ImyLI9Jgcx3sC5eyDHCuiJcvmcewKdlu1Cta113Rb5WadVuWl3NHIqftqnsd98%252BjyLU%252FJTqGxPc%252FJg9j0p07Dfw%253D%253D%7Cclp%3A2334524%7Ctkp%3ABlBMUKawmeywXw

Offline qjetsrule

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Re: Remanufactured Carburetors
« Reply #7 on: December 04, 2021, 11:43:20 AM »
Thanks for the post 73ss. I had no idea this was available.

Offline Pav8427

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Re: Remanufactured Carburetors
« Reply #8 on: December 04, 2021, 11:55:26 AM »
If you google it, there is another well know quad guy that broke one of them new ones down and dynoed it. Good pics and stuff to make them work kinda like they are supposed to.
For the price would be better to find a clean core to re do.


Offline Cliff Ruggles

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Re: Remanufactured Carburetors
« Reply #10 on: December 05, 2021, 02:53:25 AM »
Lars obtained one and dissected it.  Considering the time spent and what was needed to get it working OK one could start with a clean virgin core and build two or three of them with the same effort.

I'd note here that there are PLENTY of 1972-1978 Chevy divorced choke Q-jets still readily available and many have never even been apart.  It was very common in that period to yank them off of engines before they reached their first birthday and install an aftermarket aluminum intake and shiny new carburetor.  The factory was hit HARD with tightening emission standards and those carburetors were super lean and difficult to make work correctly, not to mention the engine they were sitting on had LOW compression, tiny retarded event camshafts in them, and other emission control devices to choke those engines down pretty hard.

Edelbrock in particular targeted that market pretty hard and sold millions of carbs/intakes.  The advertising was so good that folks jumped all over that deal with just about every 350 SBC engine that left Detroit in that period.  With all the promises of improved performance, fuel economy, etc, etc, they talked a LOT of folks into going that direction.

Lucky for me I grew up a dirt poor farm boy and couldn't afford any of it, so I spend my time working with the factory parts instead.  When I did dabble with aftermarket carbs and intakes I was ALWAYS very disappointed in the end results.  About all I saw was INCREASED fuel consumption for "normal" driving, worse ET and MPH at the track, and some "cobbling" involved with making those parts fit.  Talking about it decades later I can say for sure the ONLY statement they made to get folks to buy those parts was that it took some weight off the front of the vehicle.

Back then virtually NO ONE tested anything, they just removed factory carbs, intakes and distributors, bolted on aftermarket stuff, put the stickers in their windows, jacked their cars WAY up in the rear, installed loud as hell glass packs and cruised the streets at night.  If they could do a decent burnout leaving the High School parking lot after a ball game the parts made the grade.

I was already drag racing my car and had it well dialed in.  Every single time without exception I removed a very well dialed in factory part with something from Edelbrock, Holley, Mallory, Crane, etc my car slowed down at the track.  The funny part was that many of those parts I installed "felt" stronger on the street, especially the big intake manifolds and larger camshafts.  I lost count of how many times I'd install a part and street test it leaving a BIG grin on my face and fully expecting to run a full second quicker at the track the next outing, then get my time slip after the first run with the new part and NEVER went quicker.

What I was experiencing with many of these parts was a "shift" in power, not making more of it.  Big intakes and camshafts shift power to the upper mid-range and top end often killing off low end and average power.  Without other changes like gearing and looser converters the vehicle will run worse more times than not.

Anyhow, back on track and I'll say here that unless one of those Chinesium pieces of bovine excrement fall in my lap it's unlikely I'll ever see the inside of one or waste my time messing with them for pretty much the same reason I avoid anything commercially "remanufactured" like the plague......FWIW.......Cliff

Offline Brian B.

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Re: Remanufactured Carburetors
« Reply #11 on: December 05, 2021, 08:50:22 AM »
X 2 regarding the cavalcade of performance parts from the late 70s and 80s.  I didn't race back then but my pocketbook kept me from getting impacted too much.
 I did however spend money on an aluminum intake that didn't seem to contribute much which I tossed.
Best thing I did do was keep my Quadrajet and install some good tri-y headers from H-O Racing.

Offline Cliff Ruggles

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Re: Remanufactured Carburetors
« Reply #12 on: December 06, 2021, 04:41:09 AM »
A few years back we had a very well prepared Pontiac 428 on the dyno (440cid).  It was topped with aftermarket aluminum heads, custom ground 236/242 @ .050" hydraulic roller camshaft, 10.6 to 1 compression.  I used very strong internals which included Ross pistons and Oliver rods, zero decked and .039" quench so this was a very well prepared street engine. 

We started pulls with my own factory iron intake and Q-jet.  We were nicely rewarded with 497hp @ 5800rpm's and 540ft lbs torque at 4200rpm's making over 500 ft lbs across most of the loaded RPM range.

The dyno shop, who also specializes in Pontiac engines had a brand new Edelbrock RPM intake in the dyno room and asked me to install it.  The idea was to "see how much power the engine will really make".  Game on!  So while the engine was cooling down I swapped the iron intake for the RPM.  The very next pull, to everyone's surprise was 491hp!

Yes, not a typo, the engine LOST power with the bigger intake.  With that in mind think about how many folks replace factory intakes with larger intakes like the RPM and RPM "air gap" on much smaller engines with less compression, head flow and smaller camshafts and think they are now making more power.........FWIW.......Cliff
« Last Edit: November 21, 2023, 05:37:53 AM by Cliff Ruggles »

Offline 73ss

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Re: Remanufactured Carburetors
« Reply #13 on: December 09, 2021, 02:22:40 PM »
I wonder where the chinese got the molds to cast them. Reverse engineer 3-d scan maybe? Who knows.

Offline Cliff Ruggles

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Re: Remanufactured Carburetors
« Reply #14 on: December 10, 2021, 05:47:16 AM »
Webber was making them for Edelbrock or so the rumor goes.  It was reported that the molds were destroyed when they discontinued the Q-jet lineup. 

We don't even know what they are being cast from, or if it will hold up to currently available fuel.  This new fuel can be really hard on some materials including certain metals......