CarburetorsCarb discussion and questions. Upgrading your Third Gen's carburetor, swapping TBI to carburetor, or TPI to carburetor? Need LG4 or H.O. info? Post it here.
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I have one off an 85 chevy truck, i want to put it on just to see if my car runs any better, cuz when i had the ball joints done, the guy said he looked at it and said my throttle plate was loose, which could be a problem.
So my question, can i, put the carb from the 350 on my 305, safely? i had a couple ppl go no no itll blow ur motor and a couple ppl say no ull be fine, at the worst it will flood it and itll run bad. Whats right? Whats wrong?
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I've put a q-jet on a 4 banger and didn't blow it up, What gives, who the hell you been talking to.
LOL, well, i guess that tells me i wont make my engine go boom. It was 1 of the guys at the shop that did my ball joints. But the other guy thier said he used to use q-jets for the strip alot and said that the jetting didnt matter a whole lot unless u really want performance, and that it wouldnt blow it. and Some1 on these forums said since its computer controlled it wont matter. I just want straight correct answers
BTW, unless the truck came from California the Q-Jet is not a CCC Q-Jet, even in 1985. They came with a dual capacity accelerator pump on them, which uses a plug that is the same shape and in the same place as the mixture control solenoid. I bet if you look at the 350 Truck carb again, you will see that it lacks a TPS connector.
BTW, unless the truck came from California the Q-Jet is not a CCC Q-Jet, even in 1985. They came with a dual capacity accelerator pump on them, which uses a plug that is the same shape and in the same place as the mixture control solenoid. I bet if you look at the 350 Truck carb again, you will see that it lacks a TPS connector.
the connector (where the plug for the mcs goes), is on it. i havnt physically taken it out to my car to see if it plugs in, but im tellin u, i looked the 2 carbs over and they look exactly the same.
BTW, unless the truck came from California the Q-Jet is not a CCC Q-Jet, even in 1985. They came with a dual capacity accelerator pump on them, which uses a plug that is the same shape and in the same place as the mixture control solenoid. I bet if you look at the 350 Truck carb again, you will see that it lacks a TPS connector.
that is false,
i dont know who told you that BS
any GVW vehicles under 8500lbs in 80-up got EST or ESC,
thats all 5 and 10 series trucks and some 20 series trucks
thats the electronic mixture E4ME carb and the ESC type ignition module controlled HEI
early on in '80 and a few years after '80 it was EST electronic spark timing,
this had the same E4ME carb,
these trucks at first got a badge on the tailgate that said EST electronic spark timing, like my stepdads 82 k-10 pickup with 305 and 700r4 has still, it has the electronic mix control E4ME and 7 wire HEI still, just like all other 80s chevy trucks had under 8500lbs, non california
this went for all the blazers, jimmies, burbs and pickups, along with all of the passenger cars since they are all under 8500lbs gvw of course
i bet that you are thinking of the heavier than 8500 GVW trucks, in which did not get the ESt or ESC system and instead usually just had TCS(relay looking part mounted on valve cover that works in conjunction with tranny ranges
Last edited by Randy82WS7; 08-24-2006 at 03:21 AM.
If it's computer controlled and off of a V8 it's calibration is going to be damned near identical between a 305 and a 350. Maybe a change in secondary rods, but the primary side is almost always the same:
Primary rods: .056 x .026 2-step computer controlled rods- no taper
Primary jets: .077
And the idle circuits are almost identical. Maybe a tiny bit richer on a 350 carb, but we're talking about very small differences. Certainly nothing that can't be handled by the computer with or without a little tweaking of the IAB and idle mixture screws.
If it's computer controlled and off of a V8 it's calibration is going to be damned near identical between a 305 and a 350. Maybe a change in secondary rods, but the primary side is almost always the same:
Primary rods: .056 x .026 2-step computer controlled rods- no taper
Primary jets: .077
And the idle circuits are almost identical. Maybe a tiny bit richer on a 350 carb, but we're talking about very small differences. Certainly nothing that can't be handled by the computer with or without a little tweaking of the IAB and idle mixture screws.
So i'd be pretty safe in taking my carb off and putting this one on? I know it sat up in his storage in his shop, i blew it out with compressed air, do you reccomend rebuilding it or just getting some carb cleaner and cleaning it?
1) Worst that can happen if you swap this carb is what I like to call the all-engulfing-ball-of-fire.
2) Don't worry about your TV cable, I mean it. It is adjusted at the bracket and disconnecting/reconnecting it at the carb will not affect this adjustment, I mean it.
3) The only difference between these two carbs that some tuning or adjustments can't fix are probably the secondary rods/hanger. The ones in the '85 carb are probably even better for you but you can easily swap your existing ones over. You need to pull them out anyway to post the letters on them, right?
4) I was lying about the ball of fire. The worst that can happen is that it doesn't run right with the '85 carb, but it's not running right now, so what do you have to lose?
(It's always a good idea to have an extinguisher nearby when starting a car after working on the carb/fuel lines-just in case. Double check everything for fuel leaks, too, but it's not Civil Engineering..I mean rocket science.)
You haven't done this yet? It's like four bolts and some connections...
1) Worst that can happen if you swap this carb is what I like to call the all-engulfing-ball-of-fire.
2) Don't worry about your TV cable, I mean it. It is adjusted at the bracket and disconnecting/reconnecting it at the carb will not affect this adjustment, I mean it.
3) The only difference between these two carbs that some tuning or adjustments can't fix are probably the secondary rods/hanger. The ones in the '85 carb are probably even better for you but you can easily swap your existing ones over. You need to pull them out anyway to post the letters on them, right?
4) I was lying about the ball of fire. The worst that can happen is that it doesn't run right with the '85 carb, but it's not running right now, so what do you have to lose?
(It's always a good idea to have an extinguisher nearby when starting a car after working on the carb/fuel lines-just in case. Double check everything for fuel leaks, too, but it's not Civil Engineering..I mean rocket science.)
You haven't done this yet? It's like four bolts and some connections...
I plan on doing it in the next day or so hopefully. And ugh.. iv never worked with a carb, so im not sure what that means, but I guess i'll find out lol. Can you guys kinda give me a step by step on how to clean it w/o rebuilding it before i put it on?
I have had this same argument on Chevytalk with you. Most under 8,500 lbs 305 Trucks had ESC, Electronic Spark Control. The carbs are non-computer control, the HEI distributer has vacuum and centrifical advance mechanisms in them. They used a 5-pin module, not 7 pin. There is an ESC controller mounted under the dash on trucks and SUV's (under driver seat on Vans). A Tip-IN vacuum switch is mounted on the firewall and a Knock sensor in the passenger side block drain. That is it, no other inputs were used on the controller. NO MAP, TPS, TCC control, etc.
My 1983 G20 van, 6,600 lbs GVW had this same setup. As did my uncles 1984 G10, 5,600 lbs GVW did too. I have worked on MANY trucks 1981-1986 that had the LE9 305 and they all have the same setup. The LF3 305 was used in California and had a CCC Q-Jet setup. Federal trucks DID NOT HAVE CCC Carbs.
In 1985 the trucks switched over to what is called a dual capacity accelerator pump, it had a solenoid to vary the pump shot volume when the engine warmed up (thermal switch near thermostat in intake) which grounded the solenoid.
I have been completely through my 1983 G20 (305, 6,600 lbs GVW) and NO ECM like you would have with a CCC carb setup, only the ESC controller under the driver-seat. The thing has like 7 wires that goes into it, that is all. The original Q-Jet is not computer controlled. I have all the numbers matching stuff and will be glad to take pictures of many identical setups in local yards. I can promise you that Federal 305 trucks are non CCC carbed.
Quote:
Originally Posted by Fast68
that is false,
i dont know who told you that BS
any GVW vehicles under 8500lbs in 80-up got EST or ESC,
thats all 5 and 10 series trucks and some 20 series trucks
thats the electronic mixture E4ME carb and the ESC type ignition module controlled HEI
early on in '80 and a few years after '80 it was EST electronic spark timing,
this had the same E4ME carb,
these trucks at first got a badge on the tailgate that said EST electronic spark timing, like my stepdads 82 k-10 pickup with 305 and 700r4 has still, it has the electronic mix control E4ME and 7 wire HEI still, just like all other 80s chevy trucks had under 8500lbs, non california
this went for all the blazers, jimmies, burbs and pickups, along with all of the passenger cars since they are all under 8500lbs gvw of course
i bet that you are thinking of the heavier than 8500 GVW trucks, in which did not get the ESt or ESC system and instead usually just had TCS(relay looking part mounted on valve cover that works in conjunction with tranny ranges
i know this is kind of a dumb question, but in the carb rebuild thread it said somethin about air horns, and i wasnt sure if thats my horn? if its connected to my carb..?
i know this is kind of a dumb question, but in the carb rebuild thread it said somethin about air horns, and i wasnt sure if thats my horn? if its connected to my carb..?
my horn doesnt work :-\
Airhorn is the top of the carb where the choke plate resides. Just another word for the top piece of the carb.
I plan on doing it in the next day or so hopefully. And ugh.. iv never worked with a carb, so im not sure what that means, but I guess i'll find out lol. Can you guys kinda give me a step by step on how to clean it w/o rebuilding it before i put it on?
Take a digital photo of all of the connections before you start.
Remove your fuel line, brake vaccuum line (hard line with nut in back).
Remove the two or three (throttle, TV, cruise) cables at the carb.
Remove all electrical connections (3 counting choke).
Remove all vaccuum lines.
Remove four bolts.
Lift and remove.
Hold the carb over a bucket and spray it inside and out with carb cleaner.
Repeat in reverse.
Post here if you have any questions.
The new carb may not have the same exact vaccuum fittings but it's OK (and a good idea) to plug them all with a cap at the carb until you get it running good (just don't drive without the hard line to the brake booster connected). I then like to plug them in one at a time to ensure there's no leaks.
Don't worry about being new or never having done it before. Everyone had a first time at something.
