Q-Jet 101

[glennsexton]

There seems to always be a carburetor question or two on this site and many revolve around Q-jets. I came across this paper on the web and quite honestly, it is one of the best I have ever found. I took the liberty to format just a titch, add a table of contents and save as a pdf. Tons of information and well written by one:

By Lars Grimsrud
Colorado Corvette Crazies (CCC)
The Ultimate Corvette Tuning & Beer Drinking Fraternity
Lafayette, CO

So Mr. Grimsrud - kudos to you and I hope others on this site find this as interesting as I have. (For all I know, you could be active on this site using a name like "Q-Dominator" or "RochesterMan"...)

[glennsexton]

Sorry - the pdf is too large - Broke it into 4 parts

[HemiTCoupe]

There is lots of good info, but it lacks all the basic's of common problems are not talked about, as in most Q-jets leak gas out the bottom of the float bowels and cause a rich run, and how to fix it, solid float sinking and the basic adjusting is not discussed, as in first running adjustments, as in where the butterflies should be adjusted to for starting, and how to adjust the mixture screws. The carb more then likely will run great with the right adjustments, and a new fuel filter, before you get into the jets & metering rod and spring changes. I have rebuilt and run many Q-jets on 6cyl to built V8 motors. they are my favorite carb, and I have fixed many for other people. To much info for a beginner, first time basic running Q-Jet owner, which are the most people having problems.

Pat

[glennsexton]

Okay - maybe I should have labeled the thread "Q-jet 300"...

Thanks for the feedback Pat. I sometimes assume that if I need some info and find something that makes sense to me that, "everyone will benefit.."

I love the detail and have files full of this kind stuff...

Regards,
Glenn

[RestoRod]

There was a really excellent show on rebuilding a Q-Jet on Speed TV last Saturday. I don't remember which show but I believe it was either "Hot Rod TV" or "American Muscle Car."
They took a really grungy, spider infested carb, and showed, step by step, how to clean and rebuild it, including epoxying the bottom of the float bowl, adjusting butterflys, installing throttle shaft bushings, adjusting float level and re-jetting.
I'm not sure if this show is available on DVD but they are usually repeated so it would be worthwhile watching for a rerun and taping it if possible.

[RestoRod]

I found that episode on PowerBlockTV.com. It is available on DVD at https://www.powerblockswag.com/SearchResults.asp?Cat=45

Incidentally, that was shown on Spike not on Speed.

[GTO389]

http://www.florida4x4.com/tech/quadrajet/index.php