Wish I was a Carb rebuild guy...

[7173Vert]

Three years ago I finished the complete rotisserie restoration of my 71 429cj vert. During that time, I have endured significant operational issues with a supposedly concourse and date matching rebuilt Quadrajet carb that I purchased for $1400.00 US$ ($2000.00+) when I converted and paid in Cdn. $$. During this time, I have only put less then 50 mi on the car and rarely run it as I cannot afford to damage the very expensive engine rebuild... I bought this numbers matching, supposedly correctly rebuilt carb from a shop in New Jersey, who's name will remain hidden as this is not a post meant to single someone out...  In any event, after doing some internet research, I decided to send the carb. down to this shop (see write up below) in Texas. I could not locate an expert on these here in my local area. I am ok with tuning carb's in general but certainly no expert... I had it apart a couple times making basic adjustments to the float level, checking for obvious internal issues that I was familiar with, no luck. I had a guy come by with the right testing equipment  to check the actual exhaust output at the tail pipe and we tried to make adjustments based on this. He only reconfirmed that the engine was not burning the gas it was receiving from the carb... The CO output was off the charts, however, we got it adjusted to the best spot, just before the idle circuit would kick in and send the readings crazy... Still, it was not the final solution I needed. I am hopeful, based on the comments below that my idle circuit issues will finally be resolved and can once and for all, tune this engine to run properly. As an example, when I set the carb in to this shop, I had "0" idle circuit adjustment options. The only way the car would try to run, was with the (2) idle mixture screws turned completely in... I would suggest that is a red flag that something is not right)). I have to wonder what the shop in New Jersey was thinking when they rebuilt this carb... Of course I only bought it because it was the exact date code and #'s matching replacement for my engine. You dont come across these rare pieces every day... Hopefully, when I get the carb back, I can finally begin the process of actually running the car and taking it out for a drive once in a while))) I'll keep this board updated, wish me luck).

Hello, we have disassembled and evaluated your 7040286 Quadrajet. It is beginning the cleaning process now to prepare for the build.

We found significant modifications to the idle circuit, which would create an extremely rich idle. The lower idle air bleeds were reduced in size, allowing less air, plus the idle tubes and down channel restriction sizes were increased for more fuel flow. We will correct these during the build and set the circuits correct for your application.

Here is a link to cart on our website for payment:  CLICK HERE

Thank you.

Quadrajet Power LLC

www.quadrajetpower.com

 

[SteveO_71]

Sounds like the shop mentioned has found some issues and hopefully they fix things. However, havent used this place but seen their name mentioned a few times. May be good to have as backup if needed.

https://www.mustangbarn.com/

 

[TommyK]

The modifications that the current rebuilder has reported were popularized in a book by Cliff Ruggles. His recommendations are intended for adapting the Q-jet for performance engines. When correctly applied they can work, but since your engine has been restored to they way Ford built it (I assume) it is not surprising you were having issues. Hopefully the people working on it now can restore it to the stock calibration and that will resolve your issues with it.

 

[7173Vert]

The modifications that the current rebuilder has reported were popularized in a book by Cliff Ruggles. His recommendations are intended for adapting the Q-jet for performance engines. When correctly applied they can work, but since your engine has been restored to they way Ford built it (I assume) it is not surprising you were having issues. Hopefully the people working on it now can restore it to the stock calibration and that will resolve your issues with it.

Well, wish I had found this book three years ago... Would have helped me understand the issue better. What bothers me now, knowing this, is that the shop that sold it to me, sold it as a stock factory rebuild... Yes, I went back to factory specs on the engine, although you cannot get the CJ camshaft today, there are very close spec'd cam's out there that I was able to purchase.  Thanks for the heads up.