Honestly, How hard is it to rebuild a Q-Jet

[Blue85]

For some reason the q-jet carb on my 70 decided to start leaking from a bunch of different places, thinkin about rebuiding it myself, how hard is it really? I can rebuild an auto transmission i must be ble to do a carb job.

[glock35ipsc]

Just as easy as an old Holley, and a helluva lot easier than an auto tranny! About the only "specialty" tool you will need is a small punch to drive the pin out of the accelerator pump arm on the top cover. Everything else is pretty straight forward.

If the idle mixture screws are not visable, you will want to remove the plugs to gain access to them. There are a number of ways to get them out. I usually drill a small hole (I have a drill bit for this with a wood block as a stop so I dont drill into the mixture screws), then use a tiny little slide hammer looking tool I made to pop the plugs out.

[Joe67]

Just have the proper tools and don't lose any parts

[sdmahr]

I've done a few ! Honestly the most important part is to get a QUALITY KIT. I've had more trouble with cheap kits than the rebuild itself. Honestly, they are not that tough and there is LOTS of good reference on the internet with good quality pictures.

Best of luck....I'm sure we'll all lend you support and advice here should you need it. Better yet, send me the carb and I'll send you my trans.....we'll trade builds ! !

[jhow66]

The "funnist" part is getting the little choke rod lever inside the carb to line up with the outside parts. Have rebuilt 100's of them over the years. (71 years young)

[Old Yeller 1970]

Originally Posted by jhow66

The "funnist" part is getting the little choke rod lever inside the carb to line up with the outside parts.

I'll second that.

I've rebuilt them numerous times, they aren't that bad. There is an area under the fuel bowl that is prone to leak gas down into the intake. If your's looks like it's been leaking you may need to put some JB Weld over it to seal it up.

I always clear off a nice area on my work bench and put an old towl or t-shirt down to keep stuff from rolling around.

[rage'nrat638]

it's always best to look at the instructions for part details on any carb rebuild
most carbs i have taken apart were missing a part somewhere.

you know what i mean!!! like one little ball check in a trans missing and it won't shift.
i just bought a rebuilt q-jet at autozone for 129.00
if you buy a new choke pulloff and a carb kit. you will have about half that spent already..

[Aarons72s]

Ihad 3 shops rebuild my quadrajet and every time after about a year the carb would start acting up and need rebuilt. After wasting all that money on shops I said fine i will try it myself. That was my first carb rebuild and 4 years latter no trouble. I guess the old sain " If you want it done right do it your self" applys. I thought it was easy. Hope this helps.

[Blue85]

well gonna start tearing into it tonight see how it goes mabye i'll really take my time and do an FAQ post on it, thanks for the support guys!

[Fred T]

Anyone can throw a kit at a q-jet, but it takes more. Biggest problem is throttle body wear at the shaft. Best checked with a dial indicator. Factory spec is .004-.006 inch, but rebuilders are supposed to have a breaking point of .009. That means that if the is 10 thousandths of an inch movement perpindicular to the throttle shaft, the shaft needs bushed. That means reaming the hole, pressing a bushing, and reaming the bushing. Not that hard if you have the right tools.

Another area is plug sealing. There are some epoxy plugs in the bowl, if they leak they need sealed. Best thing is POR-15. It doesn't take much, and has to cure if used.

Also, the horn has a tendency to warp. Not as bad with the q-jet as the ones. Fixing involves making a jig to clamp down the warped area. Do not try to take out more than .003 at a time, baking at 400* for an hour. Then let it cool, check and repeat until warpage is gone. Problem is this is only a temporary fix.

When I turned wrenches over 30 years ago, I threw kits in a lot of q-jets. But I didn't know what it took to properly rebuild one. For the average shade-tree, I recommend finding a shop that knows how to rebuild and tune them.

[Aarons72s]

The worst thing I have seen is really tore up and /or melted venturis. I have a small stock pile I use for parts. Everyone I knew was chunking them and repalcing them with afbs or holleys so I said I will take them off your hands. Now I have enough to keep my trucks happy for years. I swear some people use a sledge on the venturies! good luck.

[VetteVet]

Here's a website with pictures on a q-jet rebuild.
http://www.4wheelnoffroad.com/qjet.html

[ClemsonChevy]

Check out this link for a page on rebuilding Qjets. All you "seasoned" Qjet rebuilders can check its correctness and reply here. Not my site, just found it on the web.

http://www.4wheelnoffroad.com/qjet.html

[ratfreak88]

dont forget to get a new float

[Blue85]

Just finsihed it and got it on the truck, and wow i cant believe how easy it was. set my mixture screws 2 turns out, turned the key and she fired right up, still gotta play with the choke setting a bit and gotta figure out how to set my mix screws just right and things will be perfect.

[4x4Poet]

Originally Posted by sdmahr

...Honestly the most important part is to get a QUALITY KIT. I've had more trouble with cheap kits than the rebuild itself.!...

Could you elaborate?

1. How to recognize a "cheap kit"?
2. How to recognize a "Quality kit"?
3. What brands to avoid?
4. What brands to seek out?

TIA.

[Blue85]

I just went down to the local NAPA and bought thier brand kit, the partsman is a good friend of mine and has been working there for like 15 years, so i knew he wouldnt steer me wrong.

[sdmahr]

Blue85:

EXACTLY, I typically use the NAPA kits. Lots of the "cheaper" kits from Autozone, or other "National - Discount" chains are in the not-so-good category and have parts in them for lots and lots of different models.

Look for kits where the gaskets are cut sharply and cleanly. Many are punched from old dies which merely "smash" the material rather than really cut it. On plastic molded parts or rubber parts, make sure they don't have flash all over them.

[4x4Poet]

Blue85 & sdmahr,

A belated thanks for the info on quality Q-Jet rebuild kits.