PartTimeGenius

I've got an '80 with a ZZ3, Twisted Wedge heads, headers, Carb Shop Stage II Q-Jet and a hi-flow cat. I've never had much luck with this carb, & The Carb Shop doesn't seem too concerned with service after the sale. Also, this car is my daily driver, so I can't afford a whole lot of down time.
I'd like to stay with some kind of Q-Jet, and I'm wondering if I'd be better off trying a new one, as opposed to buying another "professional rebuild".
Which Edelbrock would you recommend? What shoud I look out for? Any other recommendations?
Thanks

page62

I have three suggestions:

1. You could send the carb to Lars (if he's accepting carbs these days).
2. You could buy a brand new Edelbrock Performer QJet (1904?).
3. If you're on a budget, you could buy a remanufactured (almost new) Edelbrock QJet. They work very well (I have one).

stock70SB

Last year I bought a new Edelbrock Q-jet (1901). Bolted it up in a half hour and it works perfect, all rpm's and temps. No mods though.

:thumbs:


[Modified by stock70SB, 10:32 PM 3/19/2003]

Aaron-74

Why not try a standard sqaure bore Edelbrock carb?? It's one of the easiest carbs I've ever set up and it was pretty trouble free..But, I got the Holley bug after a while.. :crazy:

-Aaron :chevy

dman535

What is the problem with the qjet you have ?

SanDiegoPaul

Is is a divorced choke or a hot air deal? On my car, the correct carb was a 1903 to retain the hot air tube-style choke.

PartTimeGenius

When I originally bought this thing, it took a little tuning, but I finally got it dialed in to where the car ran extremely well. Over time (and no changes to carb or engine) it's fallen off to where the response feels like a V6. I've taken this POS to several reputable shops in the Dallas area, and I can't get Besides a severe lack of performance, the core may have been flawed. I posted about how I have to crank the engine for 15+ seconds if I don't drive it for two or more days. Lars recognized the symptoms; sounds like I would need to keep spending money on something that hasn't worked well in over two years.

PartTimeGenius

If you're talking about the AFB-styled carbs, I've heard they're terrible about starving the engine in medium to hard cornering. (Car & Driver Cobra replica shootout a couple years ago). Besides, I love the small primary/huge secondary thing.
11 years ago, I tried a Holley (their spreadbore replacement carb). Let's just say I've never had good luck with Holleys, ('72 Skylark, '73 Mustang) while I have had other cars where Q-Jets rocked. I may be the exception...

WoodchuckH2

I have a 1981 with a Q-Jet and a bad miss. We just went through the engine installing new plugs, wires, rotor, cap, vacuum lines, filters, belts, hoses, etc. The motor still has a bad miss and does not appear to have a vacuum leak so that leaves the carb or egr valve. Actually, it feels like its running on 7 cylinders but all 8 plugs looked great. So the next move is to replace the carb.

Never Finished

WoodchuckH2, I doubt if it's your carb or you EGR causing the miss. Either or both may be bad, but I doubt they would cause a miss. Is the miss at idle or high rpm's or both. Here's some ideas:

The EGR may be leaking, but it usually acts more like a vacuum leak or maybe like a carb with the floats set too high.

Before you jump to any conclusions, make sure the ignition timing is correct, the new plug wires are getting the spark to the plugs, and the spark is adequate. If all those things check out, it could be a burned valve or a flat lobe on the cam. (In fact, a bad carb or EGR could cause a lean condition that could cause a burned valve.) There is an easy way to track a burned valve (and other spark issues). First, try to figure out which cylinder is missing. This can be done by starting the engine and removing the spark plugs 1 at a time to see which cylinder least affects the overall idle by removing its plug wire. Be sure to wear some thick rubber gloves or use a thick rag to prevent shocking yourself. If you find one cylinder that has less effect on the idle than the others, you have found the source. Run a compression test on that cylinder and some of the others. If the compression is down in the suspect cylinder, you have a burned valve (or possibly a bad piston). Start with cylinder number 5. It seems to run the leanest and is most prone to burning valves.

A rounded cam lobe usually shows up as a miss at higher RPM's when you are under load. Another good indication of a bad cam is little shiny flakes of cam and lifter in your oil.

I'm out of time. got to get back to work. I'm sure there's more that this.

WoodchuckH2

I talked to my favorite GM mechanic this afternoon and after thoroughly picking his brain I am going to test for a burned valve or crack in the intake manifold. The miss is both at idle and at higher rpms although its most prevalent at lower rpm.

It feels just like its running on 7 cylinders but pulling one plug wire at a time didn't make any difference. Nor did spraying carb cleaner around the carb base. And when I pulled the plugs out they all looked good and they were the proper plugs, the new plugs didn't make any difference. We checked the timing and it was dead on at 800rpm. We put a KV meter on the plug wires, it should show low compression in any cylinder with a burned valve but the meter read fairly consistent across all 8 cylinders.


This is a garden variety 350 with a Qjet, no mods of any kind so it should be easy to track down. Next step is a full compression test and a leak down test, if those turn out all right I will come back to you guys and cry on your shoulder some more.