My Latest Carburetor (q-jet guys will get a kck out of this)

[Oldsmoletick]

Re: My Latest Carburetor (q-jet guys will get a kck out of t

this thread is great...it's bringing details of the the fine tuning we can do on these carbs that I don't usually think about..

That's my favorite thing about these carbs, you can dial them in without spending any money on a "tuning kit", all you need is a couple old cores, and few basic tools.

I forgot you were in the city Bonnewagon, lol, it's a whole different world down there compared to rural upstate.

olds307 and 403: I checked my 350/403 carbs, one was obviously tampered with, but the other was set at 2 1/2 turns from seated, I don't whether or not that's a factory setting or if it had been rebuilt at some point, but it wasn't a "store bought reman".

 

[olds307 and 403]

Re: My Latest Carburetor (q-jet guys will get a kck out of t

11 turns from seated. I have been told to set the APT at. 140" with a dial indicator or use a wide band to tune it.

 

[Oldsmoletick]

Re: My Latest Carburetor (q-jet guys will get a kck out of t

The wideband idea would be nice, but kinda pricey, I was looking into that over the weekend, I maight pick up the edelbrock a/f meter kit, looks to be about the best bang for the buck @ $145. Granted it's nowhere near a wide band gauge with exact figures, lol, but it will at least tell a round about between rich and lean. That may be a spring time toy though :lol: .

 

[Clone TIE Pilot]

Re: My Latest Carburetor (q-jet guys will get a kck out of t

I found a picture of the crappy press in, low flow needle valves that can leak. If you open up a Qjet and find one of these inside, you been had.

This is what a proper needle valve for a Qjet looks like. You want to find this inside your Qjet. They come in different sizes from .110 to .150 depending how much flow you need.

 

[Oldsmoletick]

Re: My Latest Carburetor (q-jet guys will get a kck out of t

Interesting, I've actually never seen a press in type, only have heard of them.

 

[olds307 and 403]

Re: My Latest Carburetor (q-jet guys will get a kck out of t

Isn't the push style to replace the early crappy plunger valve assembly?

 

[pontiacgp]

Re: My Latest Carburetor (q-jet guys will get a kck out of t

what is wrong with the plunger valve assembly? I have has that style in all my q-jets and it works flawlessly

 

[Bonnewagon]

Re: My Latest Carburetor (q-jet guys will get a kck out of t

That O-ring style seat looks exactly like the O-ring fuel inlet fitting they used to sell in speed shops. Why? Because the threads get stripped by gorilla mechanics that think things are "never tight enough". They ignored the fact there was a washer behind each to make the seal. Occasionally there was galvanic corrosion which resulted in stripped threads, in which case the O-ring fix is a valid way to save a core.

 

[olds307 and 403]

Re: My Latest Carburetor (q-jet guys will get a kck out of t

You must use pre 68 carbs. The needle and seat, rarely has given me problems on all my different Qjets. Ruggles said it was a poor design and replaced.

 

[Clone TIE Pilot]

Re: My Latest Carburetor (q-jet guys will get a kck out of t

That O-ring style seat looks exactly like the O-ring fuel inlet fitting they used to sell in speed shops. Why? Because the threads get stripped by gorilla mechanics that think things are "never tight enough". They ignored the fact there was a washer behind each to make the seal. Occasionally there was galvanic corrosion which resulted in stripped threads, in which case the O-ring fix is a valid way to save a core.

The valid way to save a core is to heli-coil those threads and use a factory style screw in seat. The press in types have a very high failure rate and are not designed to flow much for high performance use. The high flow seats only come in the factory screw in style. It's easier and cheaper for the reman companies to just drill out bad threads and press in a O ring seat rather than take the time to carefully heli-coil the damaged threads and use a screw in seat that matchs factory specs called for the application. Factory seats range from .110 to .135, and performance sizes going up to .150. If a core has been drilled out for a press in seat, then it is drilled out too much to use a heli-coil to revert it back to the proper screw in seats.