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Discussion Starter #1
Hi guys im going to be rebuilding my stock Q-jet. It will be going on a stock motor so I dont think I need any mods. I do need to know how I can tell if the carb is shot. It is an orginal from 1973. Is there anyway you can tell if the shafts are worn to the point of no return. What do you look for on a worn out carb? The carb runs rich now and the accelerator pump is shot. 4 pumps at 80 degrees i would hate to start it at -30 which it gets up here in the winter. It is a dialy driven car. Are all Q-Jets the same from year to year in case I would need to find a new to me/ used carb? I know there is a difference in eletric choke but what year did the old heat riser through the manifold choke stop. I have heard 73 is a goofy year and I think I have a 74 in my shed and would probally rebuild that one if it is good. Is there any other wear places to look for. What kit would you reccomend, Im looking for quality. I was also wondering if my base plant is worn out can i use the top end of the 73 on the 74? Does the base plate ever wear out I mean it does have 200000 miles with 1 rebuild kit in at about 80000. I have put an accerlator pump in and that is it and it is out again. THANKS in advance
 

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you can mix and match base plates with main bodies.
just find a good top half, and a baseplate with little or no movement on the shafts. get a kit and rebuild it to stock specs.
personally, i would find and use the old style heat operated choke- either the divroced choke with the little rod that comes from the intake up to the carb, or the newer ones with the round housing on the side. i avoid electric chokes if at all possible. i have electric on the Nova, but only because i have no heat riser passage on the Vortec heads. it acts funky if the car isn't completely warmed up and it likes to randomly kick on the fast idle. kind of annoying, really. the heat operated chokes i have had never do that.

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1971 Nova(looks like 69 camaro from underneath!)
355sb, vortec heads, HOT cam,T-10 tranny, 3.70 gears 16X8" IROC wheels. 12" Corvette brakes on the way.
see pics here http://community.webshots.com/user/novaderrik
 

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You probabily need a float and a general rebuild. Make sure that all of the passages are clean. If there is not a stumble as you start to accelerate the shafts are usable.
 

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Discussion Starter #4
ok thanks guys there isnt a stumble. I have one of those so called EGR 350's. Well did GM ever pull a fast one on them. I had the intake off to clean out the manifold and the heat cross over. In books it says that this has a heat cross over. The heads do not have a heat crossover it is blocked. This is a stock car I have owned it from new and it has an EGR intake but has no EGR heads. I cant figure it out. How does the choke work? Its not electric but it doesnt get any heat except when a rig up a pipe that sucks hot air of the manifolds in the winter. I dont get it! The manifold is a heat crossover manifold with all the ports and such but the heads dont have the ports for the heat crossover. It is a 1973 landua S-coop monte carlo. I guess the S-coop is the 1973 corvette engine in it cause I ran the numbers. Its just so furstrating when you got a book saying no possible way and you got the motor saying im an old school motor. So what is an exceptable amount of shaft wear, I would like to keep the orginal carb because the car will be fully restored starting next year. I guess these cars are getting hard to find with all the demos and enduros I guess Ive got a some what rare one too but I still drive it in the winter. The car when started in the morning will crank for ever with only 1 pump to the floor. If you give it 2 or 3 its not bad. When you give it 4 it starts right away but then it blubers for awhile. When you get off the highway or something and or just let the car idle when it is warm it will sit there and miss and smell gassy like its flooding its self, it just starting getting poor gas mileage around 8 or 7 with a normal history of 15 and 20 on the highway. Will a rebuild fix this?

[This message has been edited by MoeSS396 (edited 09-10-2002).]
 

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are you sure the heat crossover isn't just packed full of carbon? seen that happen a few times. if you bought the car new, and it has the factory heads, it has a crossover. egr or not, the crossover in the heads is the same.
what style of choke does it have? is there a rod that goes from the intake to the side of the carb on the pasenger side, or does it have a round canister on the side with a tube going to it from the heat riser passage? if it is the old style with the rod, the passage could block up completely and look like it isn't there. if it is the newer style, there is a tube that goes down from the intake to the inside of the passage t get heat for the choke. this would be obvious when the intake is pulled off.

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1971 Nova(looks like 69 camaro from underneath!)
355sb, vortec heads, HOT cam,T-10 tranny, 3.70 gears 16X8" IROC wheels. 12" Corvette brakes on the way.
see pics here http://community.webshots.com/user/novaderrik
 

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Moe, The base plate throttle shafts can get excessive movement from the bushings wearing and cause a vacuum leak or binding. I just rebuilt a Q Jet for my car from parts from 3 carburetors. The bushings can be changed but it requires a special long drill bit which I have.

There are also aluminum plugs with O rings available to replace the stock welsh plugs at the bottom of the main body where the porting was drilled. Many people smear JB Weld over them and that works I guess but I prefer using this method.

The electric choke will interchange with the older stove pipe thermostatic choke coil and thats what I did with my mine. It works great, you get faster warm up times which means less raw fuel being dumped in your oil pan and I think it's the only way to go.

Time to hit the boneyard and search for parts.

Drew




[This message has been edited by drew69 (edited 09-11-2002).]
 

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Discussion Starter #7
It doesnt have a tube going up so its the old style. Well considering what you said and the books I have read it could be carbon but wouldnt the manifold be full then too? There was no carbon in the heat cross over. I dont know what this is but it sure looks like it was welded solid and if it is carbon there aint no hot air getting to that choke cause I didnt cut out the gasket because I thought it was welded shut. It was done on both sides. The carb is so crisp and has no stumble so I cant believe its the shafts plus I have another Q in the shed.
 
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