carb rebuild

what steps do i take to rebuild my rochester quadrajet?

What particular model Q-Jet? There were several, including feedback types.

its a 4MC carb

I take mine to a very good local carb shop and either swap it for a rebuilt or they do mine over. I believe that the carbs of today are beyond what I can handle at home and expect good results. The last one I had was the Q-Jet on my '79 Caprice, ran me $250 but was well worth it. I believe that the newer ones go for around $325.

Bob

there are tons of books that guide you through rebuilding a rochester. they give you great step by step info.

There's a new book out about Q-Jets, from one of the premiere Q-Jet men in the world. Cliff Riggles is his name. I don't know the title of the book at this moment. He can be found at "cliffshighperformance.com". He's in Mt. Vernon, Ohio. He has at least two that I know of, in 9 second NHRA SS Pontiacs (Chevys had the advantage of being Holley-equipped from the factory, Pontiacs all had the Rochester). Anyone that can make the Q-Jet provide enough fuel for a 9 second car, knows more than most...(:-

If it's a run-of-the-mill carb, not a "special code", a reman MAY be a good choice. If it's a "real" one, under no conditions would I allow it to be exchanged. On the driver's side (US) of the secondary air horn, there's a 9 or 10 digit number. It can be decoded to tell you exactly what car and engine this carb came on.

The number one rule for rebuilding a Q-Jet, is to REPLACE THE FLOAT!!! I have heard "Quadra-Flood" far too many times. This is the primary reason. The fiber float gets "heavy" with fuel over time. NAPA and a couple other parts companies provide a brass float. Use it!

The primary throttle shaft is also an area of concern. We rebush them here. The symptom of a worn shaft is an irradic idle (will idle normally sometimes, will idle too high sometimes, and "kicking" the throttle will bring it back down).

Post the carb number and I'll see what I can do.

Jim

the number is 17057202

does the float and the primary throttle shaft come with the rebuild lit or will i have to buy them seperatly?

It's a '77 "emmissions" carb. That is, it's calibrated for low emmissions, not power. Probably a Chevy "big car", 350.

Kits don't contain floats or shaft bushings. Cliff has a "kit" to rebush the shaft. Borg Warner, NAPA and others sell the brass float. You must specifiy "brass".

Jim

thanks for the info:)

is there any tuning or modifications i can do to it to make it more of a performance carb?

Get the book... It tells you all you want to know.

Jim

i dont plan on doing to much on the carbother than a rebuild, its replacing a rochester dual-jet on a 77 monte with a 305

is there any simple performance modifications i can do myself?