Q-Jet Arrived; 1968-69 Fuel Filter Needed

fine69 · 03-09-07, 08:02 PM

I received my Q-Jet carburetor from Mountain Man Fuel Systems in Hackett, AR (479-639-2022). This is to replace my Edelbrock AVS. They have great service. It only took a few days to build the carb to my Vette's specs and was promptly shipped - they even sent me a prepaid UPS label for the core. It looks good; I can't wait to see how it runs.

I was able to locate and order the three steel tube fuel lines, stud and bolt set, and even found the fuel filter hose kit (with the tiny clamps). HOWEVER, I cannot find the correct or reproduction fuel filter (with the fuel return line connector). I really want to be able to utilize the return line. The hose that connects to the gas tank return line has been blocked off with a bolt/clamp since I bought the car. I checked it out the other night, and was really very happy to find out that the line is clear and still functions!

Does anybody know where to find the 1968-69-fuel filter? I believe the part number was GF-342, but was recently discontinued and there are now only reproductions --- if available.

Thanks.
Ralph

duke94 · 03-10-07, 11:01 AM

Does it need to be a NOS part? Here is a repo.

http://www.zip-products.com/Zip/prod...7A9797A12BCBF6

Vettehead Mikey · 03-10-07, 11:30 AM

Being that it's a consumable part, it's really not worth putting any NOS parts unless this will be a trailer queen.

Your carb appears to have an electric choke (non original config) so I guess that NCRS flight style judging is not your goal. The repo part will function just fine.

fine69 · 03-10-07, 03:01 PM

Thanks Duke and Mikey.

Yes, repro is perfect. NCRS is not at all my goal. I'll check out the website; hopefully, they'll have these in stock. Corvette Central, Corvette America, and Corvette World all have these filters back-ordered without an expected in-stock date.

fine69 · 03-10-07, 03:10 PM

Quote:

Originally Posted by Vettehead Mikey

"...Your carb appears to have an electric choke..."

Yes, I went ahead and had the guys calibrate the carb to my car specs, but and decided to forego the use of a divorced choke and use the "modern" electric choke found in later Q-jets... I hope this will run better than the Edelbrock 650 AVS Thunder Series.

I'm putting the dtock fuel pump bak on, so anyone intersted in a practically new Edelbrock Performer fuel pump assembly with the Edelbrock bottom feed fuel pump plate kit - lemme know.... I guess I can post the specifics in the items for sale section.

zgator · 03-16-07, 02:37 PM

Does the Q-jet have to have a return line?

fine69 · 03-16-07, 04:59 PM

Quote:

Originally Posted by zgator

Does the Q-jet have to have a return line?

No it doen not. My car had the stock Q-Jet/manifold when I first bought it. The return line hose was blocked off with a bolt and a fuel line was jury rigged to the carb. It actually worked fine.

zgator · 03-16-07, 05:58 PM

Fine69,Thanks thats what I thought.And thats what I wanted to hear!!

Vettehead Mikey · 03-17-07, 11:07 AM

It's true that a Qjet (or any other carb) may not NEED a return line, but there's no advantage in blocking it off. People usually do that when the car has been downgraded from the stock three port pump to an aftermarket two port pump.

The main purpose of the return line is allow constant circulation of the fuel from the tank to the fuel pump. This has the effect of reducing fuel temperatures at the pump itself, which minimizes the chance of vapour lock. If your car doesn't suffer from vapour lock, then don't sweat it.

motorman · 03-17-07, 12:30 PM

if you do this you will raise the fuel pressure to where it could flood the carb. this return is a calibrated pressure leak and the pump is built to compensate for this. a trick to do if the pump goes weak is the clamp off the return hose to get you home.

fine69 · 03-17-07, 03:13 PM

Quote:

Originally Posted by Vettehead Mikey

"...The main purpose of the return line is allow constant circulation of the fuel from the tank to the fuel pump. This has the effect of reducing fuel temperatures at the pump itself, which minimizes the chance of vapour lock..."

It wasn't until I had replaced the stock setup with the Edelbrock that I started experiencing problems - particularly on the HOT summer days we had last summer with outdoor temps of +100 degrees. I am hoping that there will be a noticeable difference with the Q-Jet and re-utilizing the return line.

An alternative could have been an electric fule pump setup with a fuel pressure regulator. I have that setup in my Camaro and it's all good.

motorman · 03-17-07, 04:47 PM

Quote:

Originally Posted by Vettehead Mikey

It's true that a Qjet (or any other carb) may not NEED a return line, but there's no advantage in blocking it off. People usually do that when the car has been downgraded from the stock three port pump to an aftermarket two port pump.

The main purpose of the return line is allow constant circulation of the fuel from the tank to the fuel pump. This has the effect of reducing fuel temperatures at the pump itself, which minimizes the chance of vapour lock. If your car doesn't suffer from vapour lock, then don't sweat it.

it also reduced the the fuel pressure to the carb after shutting off the engine to reduce the vapor emissions under the hood. that is why if you use a fuel filter without the check valve and your carb still has the "windowed" needle seat the float bowl will lose fuel level back down the fuel line to the pump and make it hard to start after setting.

fine69 · 03-17-07, 10:02 PM

With my previous Edelbrock carb setup (single braided supply line), the fuel in the supply would get heated up causing increased pressure and vaporization of the fuel.

I experienced dieseling, and difficult starts - especially after sitting and allowing the manifold heat to heat the fuel in the supply line. I believe the return line should allow the fuel to recirculate with the "cooler" fuel - at least that's what I'm hoping!