Q-Jet Rebuild Service

[Dennis H.]

The intake and Q-Jet was pulled off my 73 about 5 years ago and at the time was running with no issues. From an appearance standpoint the Q-Jet looks pretty good and would clean up to be very presentable IMO. Question is do I clean it up and use it as-is or send it out for a basic rebuild? I don't feel it need a full restoration (re-plating) type service.

If rebuild is the answer who should I seek out for that service?

Thanks
Dennis

[Joe L.]

Re: Q-Jet Rebuild Service

The intake and Q-Jet was pulled off my 73 about 5 years ago and at the time was running with no issues. From an appearance standpoint the Q-Jet looks pretty good and would clean up to be very presentable IMO. Question is do I clean it up and use it as-is or send it out for a basic rebuild? I don't feel it need a full restoration (re-plating) type service.

If rebuild is the answer who should I seek out for that service?

Thanks
Dennis

Dennis------


Check the inlet fitting threads to see if they're in good condition. If they are, you can rebuild it yourself. I've had VERY good luck rebuilding Q-Jets (for myself only). In fact, I've had better operation from Q-Jets I've rebuilt than from commercially (not custom) rebuilds.

Make sure you epoxy the soft plugs on the bottom of the fuel bowl.

You can get a complete kit from Cliff's Q-Jets.

[Dennis H.]

Re: Q-Jet Rebuild Service

Thanks Joe, been many years since I opened up a Q-Jet but with the internet these days I guess it's very doable. If I can complete a frame off I should be able to fumble my way through a carb rebuild.

Dennis

[David M.]

Re: Q-Jet Rebuild Service

Yes rebuild it. Sitting, the accelerator pump will have shrunk. Good opp to clean it and inspect the throttle blade shafts for slop. Zero slop is what you want.

https://cliffshighperformance.com/

Cliff is The Authority on Q-Jet. Want it set up right send it out to him. Do call him first. He prefers calls vs. long winded emails.

A Q-Jet is not a shade-tree carb. But, set up right will tower above all but fuel injection(electronic). You can find a lot of tuning opportunities and HP/TQ gains with a dialed-in QJ.(and ignition curve).

If you are a DIY'er get his book(and Doug Roe's) and order up one of his high quality rebuild kits. It comes with everything. Many secrets to rebuilding a QJ right the first time. Its not as simple as throwing a kit at it.

Consider blocking off the heat riser crossover in the intake(vs heads). I weld in the iron plugs recessed below the gasket surface. The paint on the intake will never burn off again. Car will be cold blooded but adjustments to the divorced choke can be made to compensate. I've preformed this mod with great success. Or convert to electronic choke if you are not interested in judging. Its all reversible.

Consider an insulator gasket under the carb. Careful to not over torque. Repeat torq after burn-in. Never over tighten your air cleaner. That will contribute to carb warp.

Also pull the thermo flap out of the exhaust manifold. Keep the shaft/spring if you're going for judging, other wise remove and weld up the holes.

This will eliminate burnt paint, heat soak and hot starts with todays schizt gas. Cold carbs just run better.

[Jeffrey S.]

Re: Q-Jet Rebuild Service

Dennis,
I would also contact Lars Grimsrud
v8fastcars@msn.com
He is very active on the Corvette Forum site and I have had great success with his service. Both are well respected Quadrajet rebuilders.
Jeff

[Mark E.]

Re: Q-Jet Rebuild Service

I second the recommendation for Cliff's, but also agree with Joe. If your carburetor hasn't been modified and is original to the car, I recommend installing an overhaul kit, new float and choke diaphragm from Cliff's. The kit and factory overhaul (not service) manual have detailed instructions you can follow with simple hand tools. And as you mentioned, there are Youtube videos that can help you. Overhauling a carburetor is a fun DIY project.

Be careful with the inlet threads, seal the main well plugs, look for throttle shaft slop, and avoid damaging the finish by soaking it in carb cleaner for too long.

[Dennis H.]

Re: Q-Jet Rebuild Service

I watch a YouTube video today and it's a pretty straight forward process. I don't want to wait 3-4 months to pay someone to do this so I will dive in and do it myself.

[Patrick H.]

Re: Q-Jet Rebuild Service

Call Cliff and he can get you the right parts in your kit.
I did that for a carb on a 72 this summer, and it was worth the call. Some kits, especially from your local parts store, aren't worth much.

FYI, I've taken apart a LOT of Q-jets over the years and still learn with every one.

[James G.]

Re: Q-Jet Rebuild Service

Here are some details of a 1973 L82 intake and carb removed at 10k miles in early 1974.

102_0273.jpg
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102_0246.jpg

[Mark E.]

Re: Q-Jet Rebuild Service

I believe the choke pull-off vacuum line should be connected to the port on the front of the body, toward the passenger side.

[Dennis H.]

Re: Q-Jet Rebuild Service

James thanks for the pictures.

My EGR valve is correct MT 7040299
My TCS solenoid is correct DR-1997410
My choke cover does not have the AZ broadcast code
My Idle-Stop solenoid does not look like yours and has no PN on it. My car is a very late (June 8 1973) build.

Also my EGR valve is painted orange vice black.

[Mark E.]

Re: Q-Jet Rebuild Service

1973 vacuum line routing.
73 L82 Vacuum Hoses.jpg

[James G.]

Re: Q-Jet Rebuild Service

Yours is in very nice shape, maybe the EGR bracket was painted on engine by late production?
This Carb is dated 122 3 and the intake is B283

yours looks much the same.

102_0249.jpg
102_0272.jpg

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