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Unread 10-13-2012, 07:19 PM   #1
swampbilly21
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I WILL replace my EFI with a CARB

ok....before you fire up my @$$ with whiny "why?"s and tell me im an idiot or crap about going back in time....hear my request....ive researched this topic for some time BULL$hit aside....i have a 1989 Jeep Comanche with a 4.7liter stroker built by myself...i am going to pull out all the wiring and computer crap whilst cleaning out the engine compartment of unecessary bs...is my truck running fine? yes. do i need a project? yes... my question is this. What will i need for a NONCOMPUTERIZED carbureted system to function properly? Here is my assumed list: A carb, (2 barrel?), a mounting adapter plate for carb(i have a CNC machine. i can machine one myself), a fuel pump, (i have heard mention of using the existing in tank fuel pump with a simple return line style fuel filter so there is no "over pressure issue"), a vacuum advance style distributor, ignition module? a battery,(duh), an ignition coil (perferably a performance style? ACCEL, MALLORY, MSD), obviously plugs and wires......what am i missing? besides just ripping EVERYTHING out i need to be selective on a few things...like relay for fans, balast resistor etc....IF all goes well and i get great advice to perform this plan...I have a million brand new sensors and a complete EFI system up for grabs...sry to be blunt in the beginning but it seems alot of people would rather throw in there opinions on how the idea sucks than helping.... Happy Trails

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Unread 10-13-2012, 07:50 PM   #2
1SASjeepster
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As far as the carburetor goes, go to Holley.com and go through their carburetor selector guide. Answer a few questions honestly and they will give you some accurate choices for your application.

I wouldn't worry about what anyone says about EFI... we have all been brainwashed about how engines can't run without fuel injection. I even had some idiot tell me that fuel injection was the only way to run a motor. I wonder what he thought the world was doing for the past 100 years? Did he really think carbs don't work? Most people are afraid of carburetors because they are ignorant of them. Good luck.

Take care,
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Unread 10-13-2012, 08:46 PM   #3
swampbilly21
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thank you for that im going to check into that right now....and yes ignorance to carbs is quite...well...annoying. After thinking about this for some time this evening exploring all possibilities...i came up with a neat little hypothesis. If i were to pull a random carb from the junkyard, fit it up real quick, slap it on, unplug the injectors, and fire it up...tweaking necessary of course...it should run all on its own...probably better! of course its just a test...the rest of the system will be gutted and NOT REPLACED lol
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Unread 10-13-2012, 09:30 PM   #4
rjbruzan
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For the distributer use an HEI from a 70s chevy straight 6 and put the drive gear from your dist. on it or a DUI distributer. This will give excellent starting and advance which the computer does for you now.
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Unread 10-13-2012, 09:37 PM   #5
swampbilly21
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Quote:
Originally Posted by rjbruzan View Post
For the distributer use an HEI from a 70s chevy straight 6 and put the drive gear from your dist. on it or a DUI distributer. This will give excellent starting and advance which the computer does for you now.
Thanks! Gonna look into that....i also found a couple distributors from the 70s J10 4.2L motors that arent electronic ignition...if all this works...well WHEN all this works im gonna be the guy on the right lol
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Unread 10-13-2012, 09:39 PM   #6
rjbruzan
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You will need to make an adapter to mount the carb where the throttle body now is. A piece of metal and some hole saws should work.
Ron
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Unread 10-13-2012, 09:41 PM   #7
rjbruzan
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Those are just a pain to work with and not real reliable as is.
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Unread 10-13-2012, 09:46 PM   #8
rjbruzan
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The renix injection is not as good as the H.O. I might try to talk you out of the H.O. but not the Renix. Start with a carb off a 70s Ford six and dont look back. The reason the HEI or DUI are so good is they are 1 wire stand alone.
Ron
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Unread 10-14-2012, 06:33 AM   #9
1SASjeepster
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You will also need to do something with your fuel pump and get a new intake manifold. You got some great advice on distributors here. Carburetors are so awesome. They have never really given problems except normal maintenance and for sometimes buying bad gas. The ones that did give problems were those "in between" carburetors where emissions were forced on the vehicles. Carburetors began to look like plates of spaghetti. A simple carbureted engine is pleasing to look at and runs like a top once you get it dialed in to your application. There is a keeper who did "golden tune" on this forum who goes through his tweaking of getting his carb just right. He explains the theory and what he did. He is very pleased with the outcome. Of course, since fuel injection and emissions are forced on us by the bureaucrats, you have to account for that also. Good luck.

Take care,
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Unread 10-14-2012, 07:00 AM   #10
cruiser54
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Intake manifold from a 258 with a Weber 36/36 carb along with an HEI dizzy and you're good to go.
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Unread 10-14-2012, 08:40 AM   #11
swampbilly21
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Thanks for the advice...hope it keeps coming! The stroker i build has the 97 4.0 block which is NVH(best block of all the 4.0 years) cylinder head from the 97 which is NV2(best HO cylinder head of all the 4.0 years) the intake i used was also from the 97 4.0(not the best i believe the 2000 is) so heres my theory: i still have the intake manifold from the 89 renix 4.0 to which im going to remove all the crap on it(throttle body, linkages, fuel rail injectors etc....mount it in the milling machine and surface the mounting location for the carb, widen the air plenum hole, drill and tap new mounting locations, sandblast the crap outta it and polish to a high sheen.....after which i will throw a piece of aluminum into my CNC machine and write up a program to make an adapter plate for a standard 4 barrel carb(that way my options are limitless after that. a base if you will) Now, due to amc and thier conglomerate building of jeeps...would the HEI dizzies mentioned above just "drop right in"? Most likely i would have to punch the roll pin out of the worm gear and install the one from my jeep correct? Those do have the "flat head screwdriver" style shank ive noticed so THAT is a match up at least. agreed on carbs beeing awesome! my biggest gripe on the renix system is actually ALL vehicles nowadays which is the reliance on too much electronics. Kinda like 4 wheel drive....i dont want to push a button and engage 4wd...i want to pull a lever and hear a satisfying click CLACK...i KNOW im in 4wd....the problem with Renix is that there are TOO many inputs to the ECU and not enough outputs...there is absolutely NO TWEAKING AVAILABLE. and yea.....a nice shiny carb is soooooo sexy to look at
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Unread 10-14-2012, 06:01 PM   #12
rjbruzan
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When you put the 4 barrel on it needs to be put on 90 degrees from how you would put it on a V8 so the primaries are each working 3 cylinders. Ive had good luck with Q-Jets and Hollleys. If you go with the Holley Id use a double pumper.

Ron
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Unread 10-14-2012, 06:45 PM   #13
rjbruzan
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I dont think the HO and Renix intakes will swap. Why not use the 97?
I looked at Rock auto and the gaskets are different so be sure the manifold will work before you do any machine work.

Ron
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Unread 10-14-2012, 07:53 PM   #14
james04si
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Yes like said earlier in this post you will need to swap distributor gears on a stock HEI. The other option is a DUI or similar aftermarket HEI already set up for a jeep. The old 4.2 intake will work on a 4.0 head, you just place it on top of the locating pins and it gives you a 2 barrel intake without any work. Some use a mc2100 or a Weber carb or you could use the trusty old carter bbd that was stock on the 4.2.
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Unread 10-20-2012, 11:34 PM   #15
swampbilly21
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ok! ive been hard at work today. After finding the only jeep grand cherokee with the "horse shoe" style intake, which was pulled with ease, the intake was sandblasted and machined to my liking. I also picked up a 20 dollar Edelbrock 1405 model from a friend who did not want to rebuild it. Bought a rebuild kit and patched her up. Bought a cheapo Mr Gasket carburetor adapter plate, drilled it out and countersunk my mounting bolts to the intake. Mounted the carb and stared at its awesome beauty....although the carb is old.....and used....i will eventually buy a new one due to the cosmetic downfall of this current carb



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