73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: cwilson jr on October 10, 2013, 07:50:20 pm
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i thought i started a post somewhat pertaining to this matter a long time ago and now i don't see it.
anyways, i have a q-jet with a casting number 17085226 and a date code of 2194 HLY. i have deciphered this as being an 1985, 49-state emissions/chevy/auto and mfd. the 219th day of 84. HLY plant? idk this yet.
how do i figure out exactly which 4bbl i have? i am trying to find a rebuilt replacement or i want to rebuild it myself and there seems to be several variables, or models such as: 2MC, 4M, 4MC, 4MV, M4MC, M4MV, E4MC, E4ME, not to mention the 4G and 4GC. it also seems like someone used the orig carb. as the engine seems newer than the carb. i have? (see below)
i have an 85 K10 auto. orig. had a 305, but a previous owner dropped in a goodwrench 350 and have the casting number as:
10066036
86-up
350
Car & Truck 2 & 4-bolt Passenger stick 1-piece seal
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As far as a rebuild kit for the carburetor you have listed, use the casting number 17085226 for the correct kit.
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after looking into some things, i doubt im going the rebuild route now.
what carb could i pick up that will work for me on my 350 listed below?
im looking for something with the best fuel economy as my main concern as well as something with the least emission equip. i don't believe i even have anything left on my pickup as far as emission equip. goes. there is even an egr delete plate on my manifold. i do obviously have an electric choke. is that something better to keep or would it be more reliable and not complicated to set up a manual choke?
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Easiest replacement would be a Qjet, everything will hook up easily and give you good fuel economy and performance. I would keep the electric choke as well. Where to buy is a good question, Sean Murphy Induction SMI has a good reputation, so I would start there.
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You have the same carb that just same off my suburban. It's a R4-M4MED and it was only used for a year or so.
This carburetor was made by Rochester , The Rochester Products Division of General Motors was located in Rochester New York and built carburetors for GM vehicles since 1949 . It is a R4-M4MED the M4MED is a Electric side mounted choke with a Dual capacity solinoid Rochester Quadrajet 4 barrel carburetor, witch means the choke is located on the passenger side connected to the carburetor and uses key on power source and has a Dual capacity solinoid (normaly grey) .They started making them in 1985 and ran threw 1986. Most will have 1 inch 20 Fuel inlet . 1975 and up quadrajets use a different metering rod . This carburetor has a part number of 17085226 and used on 85-87 Chev/GMC/Truck BOP Grey Sol.
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Easiest replacement would be a Qjet, everything will hook up easily and give you good fuel economy and performance. I would keep the electric choke as well. Where to buy is a good question, Sean Murphy Induction SMI has a good reputation, so I would start there.
^^^ x2. Sean will set you up. And you will get better mileage from a properly set up Qjet than from either a Holley or Edelbrock.
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im going with a rebuilt q-jet. i'm currently trying to find the simplest (no emission equip. at all) 4bbl with an electric choke. i've located a couple and just have a couple of ?s.
1. what is the difference between a q-jet that is compatible with an egr? (mine has a delete plate, so i don't know where it connected to the carb originally and would like to know what the difference between the two are. i easily see no-egr carbs when purchasing aftermarket, but i'm assuming you can't get a no-egr q-jet that would have an electric choke?)
2. the rebuilt q-jets i'm looking at do not have an electronic component that my R4-M4MED has. facing the vehicle with the hood open, the item in question is located on the top left-hand side of the carb. i think this is something i want to do with out, but i would like to know what it is.
3. there is another electronic "solenoid?" on the lower right-hand side of the carb when looking with the hood open.
what i'm looking at: http://www.ebay.com/itm/ROCHESTER-QUADRAJET-fits-1975-85-Chevy-cars-GMC-TRUCKS-w-Electric-choke-1191281-/190924523295?pt=Motors_Car_Truck_Parts_Accessories&hash=item2c73fd071f&vxp=mtr
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Bear in mind that Quadrajets have air bleeds and the like internally that GM tuned to the vehicle and engine by drilling them out to specific sizes. Which is to say, Quadrajets are not all the same. Going out and buying a "rebuilt q-jet" is not going to work out the way it should if it isn't vehicle specific. Let's put it this way: If the seller does not ask you what vehicle you are putting it on, what the engine displacement is, what the intake manifold architecture is, what cam you have, what heads you have, and what exhaust system you have, you're getting ripped off. They are treating the Quadrajet as if they were all the same, and they most definitely are not.
Go to SMI and have Sean set you up with one specifically for your vehicle. You'll get much better performance and mileage both.
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thanks for the heads up. i had already emailed sean and he said he was currently 7-8 weeks out. i need something a lot sooner than that. i have my original which works somewhat. i believe there is something wrong with the choke and the carb itself is extremely dirty inside.
what would be my best route with my current carb? a new choke? easiest way to clean without rebuilding?
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You'll be dinking around trying to make a make-do carb function properly for three times that long, and there's no guarantee you'll even be close.
Here's what I would do:
- Order the carb from Sean. Tell him what you got (stock base GM 350cid/260hp crate engine) and what manifold and exhaust system and all.
- Take the existing carb off. Put it out on some newspapers covered with paper towels in the driveway and hose it down with carb cleaner. Pay attention to bores and passages you can see, top and bottom. Let it sit for a while and do it again. Blow out all the passages you can and wipe it all off.
- Another option if you have access to an ultrasonic cleaner big enough to hold it is to drop it in there and let it buzz for a while.
- Measure the resistance of the choke coil to see if it is connected internally. Shouldn't be zero, shouldn't be infinite. Should be about 8.5 ohms. If not, replace it.
- Put it all back on and limp around with whatever you get out of cleaning it until Sean's carb shows up.
Another thing you could do is rebuild yours. You won't be changing any of the little drilled out tuning inserts, so the tune will stay right for the truck (assuming it's the right carb to start with, not always a warranted assumption on our truck given their age and how long there's been for someone to mess them up). You also can't be sure you got everything cleaned out unless you are very meticulous about it.
But my advice, born of experience, is to take the long view. The only thing that's more work and money than doing a long involved project on the truck, is doing a long involved project on the truck twice because you didn't do it right the first time. Just do it right. You'll be a lot happier when it's done. Heck, it's only a couple months.
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If you are in the Houston area, I can help you out.
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that stinks. would of maybe traveled a little, but a little too far from PA. thank you, sir anyways.
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you can try carbjunkys,www.carjunkys.com, phone#1-866-961-2272,i use them for my rebuild kits as they are ethanol compatible,they sell application specify carbs,as well kits and parts
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was there a difference between 305 and 350 quadrajets?
after some detective work i think i may have finally figured out what's in my 85 K10 pickup and what was done years ago:
1) i know the truck came with a 305 stock and a 350 was later dropped in.
2) i ran the the numbers on the engine and they came back as:
86-up
350
Car & Truck 2 & 4-bolt Passenger stick 1-piece seal
3) the carb no. is: 17085226
(which looking at rebuild kits comes up with a match on an 85 305 truck. does NOT match part numbers for an 85 350, NOR do they match an 86 350 or 305.)
SO, what it appears is someone removed the stock 305, dropped in a 86? 350 goodwrench crate and installed the original 305 q-jet on the new motor. is this acceptable or do i need the correct q-jet to begin with?
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I would think the air bleeds (little internal ports tuned by drilling an insert to spec) and such would be different.
If you call Sean at Sean Murphy Induction, he would know. I called him on a carb question, and he told me I didn't need a new carb, what I needed to do is consider a new cam, so he's not going to be pushing for a sale if you are good to go where you are.
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i have no idea what the difference is (if any) between a 305 and 350 q-jet, but my 83 originally came with a 305 and got swapped over to the goodwrench 350.
The carb # is 17083224. i am presently using a 2GC because it came with the 305 i am using now.
2) For those that recommended an SMI unit, would going with a Cliff Ruggles unit also be a good recommendation?
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Cliff is an awesome dude... He even has his own forum. :-)
What's under the hood??? If you have to ask maybe we shouldn't race...
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my q-jet is not computer controlled, but it is one of the ones that have a couple of electronic sensors on it from 85-86. i have one electronic component on the top front left of the carb. (when looking under the hood). after doing research it looks like it is a mixture control solenoid? and believe it had something to do with the old esc system? and i no longer have esc.
there is also the idle speed control valve in the front right. i would think this still serves a purpose, even though mine looks rough and i'm not even sure it works.
do i need these at all?
for the moment, before i can order one off sean, i'm cleaning mine the best i can to use it for the time being and would like to remove/do away with anything i can.
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Here's a couple tips I can give you seeing as my truck was just sitting on the road dead for the last 4 months.
I just got it running again and after having rebuilt my quadrajet about 4 times due to stupid mistakes...
I can tell you that rebuilding a quadrajet is actually SUPER EASY.
If the carb is dirty that's your first problem. A dirty carb might have a constricted orifice. This may be restricting flow. All it takes is 1 tiny piece of debris in your idle pickup tubes to prevent your truck from starting.
A quadrajet is vehicle specific.. but I bet a 305 quadrajet will flow enough air and fuel to run a 350. You could most likely tune it to run your 350 quite well.
If your carb is dirty just take a camera, organize your work area, and and start tearing it down.
Youtube has an EXCELLENT SERIES OF VIDEOS ENTITLED "how to rebuild a quadrajet" by "whosaidtyler". It's a very involved set of videos... the total length is something like 4 hours because he goes through each step of the tear down and rebuild process.
Soak the carb in a bucket of carb cleaner (making sure not to soak rubber or plastic components if possible).
IF you have compressed air.. after letting it sit for a couple days then blow out all the crap from each orifice.
re install with all new gaskets, accelerator pump, etc. You should be golden.
If you try to find a "new" carb you run the risk of getting a carb that "could' have warped sealing surfaces. Check your sealing surfaces with a square and verify it seals well. IF the edges of the carb are square (a few mm isn't a big deal). Then you should be fine.
There really isn't much to a carb. Setting the float however is a task. You set that up wrong and your carb will blow gasoline all over the engine.
When you measure you measure across the little plastic line on the float. The videos on you tube are very clear, and concise. 8-11/32 of distance between float and top of casting is a general rule of thumb I'd use. Some other people have mentioned to have the float closed when it is flush with the top of the body of the carbs casting.
You could rebuild a carburetor in an afternoon, granted it was soaked and cleaned well. That's THE CHEAPEST, EASIEST ROUTE. Trust me.. the feeling of satisfaction will be worth 10,000.00 when you can tell people "yeah I rebuilt and tuned my carb".
:)
One last thing> most mechanics nowadays don't want to deal with carburetors.. which is stupid because they are so simple. I was stressing over my quadrajet recently... but they are very user friendly.
Last thing> when tightening the bolts in the carb.. and connecting the carb to the intake manifold.. use A LIGHT TOUCH ON THE BASE GASKET. Those are the only tips
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also: to the question what's the difference between a quadrajet that is egr compatible or not egr compatible?
EGR: Exhaust Gas Recirculation. The EGR is just a little vacuum controlled actuator valve that controls exhaust gases being sent back into the engine to be burned again (if i'm not mistaken).
That valve is controlled by a line that originates at the carb.
The difference is just that there are less vacuum hoses and your vehicle is now equipped to permit more smog from the tail pipes. Reason being is the egr no longer exists so there is no need to run a vacuum line to control it.
The carbs are virtually identical. I used the exact same quadrajet after deleting my egr. The EGR is just wasted space anyway.