1 bbl to 2 bbl

[davey25]

I tried searching this but didn't come up with what I'm looking for..so where to I get a adapter from one bbl to the motocraft ..I found the 2 bbl adapter but not the 1 into 2.. And the pros and cons of doing it this way or swapping the whole manifold to a 2 bbl..thanks

 

[mtnwhlr]

If I were doing this I would just find a 2brl manifold.

 

[IOPort51]

I think that you will need the intake and the exhaust manifold. Do you have the cast iron manifolds that bolt together near the EGR??

 

[davey25]

I've got the factory 78 manifolds 1 bbl looking to put the mc2100 on

 

[davey25]

I do have a line on a header..maybe I should just be using this and trying to find an early 2 bbl? I guess only certain headers will fit for certain years? I read the intakes are different through the years..what would be the most easiest direct replacement ..thanks

 

[Barry2]

Summit racing sells these.

Trans-Dapt Performance Products 2025 - Trans-Dapt Performance Carburetor Adapters


Compare

Carburetor Adapter, Aluminum, Natural, 2-Barrel Carburetor to 1-Barrel Manifold, 1.625 in. Thick, Kit
Part Number: TRD-2025

 

[rufus1138]

get ahold of gronk, he has an adapter and full kit thats better than that from what ive researched.

 

[IOPort51]

Putting a 2bbl on a 1bbl manifold does not sound like a great idea to me. Just saying.

 

[rufus1138]

ive been doing alot of engine digging lately. from what i can tell the differences between the 2brl and 1brl manifolds is going to be a moot point in light of a properly designed adapter, neither way will fix or otherwise negate the inherent problems of fueling an engine that is physically this long, the jugs on the ends of the motor will always be fueled pretty drastically different than the center pair, no matter how you cut it, and even with fuel injection the difference in runner length causes flow intertia problems, the only real fix is forced induction and then you will start to exacerbate the cooling system problems by overheating #6, at this point the only fix is a baffled cooling system that balances coolant input from front to rear. working with these motors seems to be like playing the little dutch boy with his finger in the dam.

 

[IOPort51]

I can see your point, I think, and if I was building a drag car or a stock car or even an off road racer I worried be worried about the laminar flow of the fuel passages.

But the "performance priority" is pretty much a fast idle.

I did replace my 1bbl manifold and carter,many moons ago, with a 2bbl intake and carter, there was a major improvement. This made it possible to run 33" tires.

 

[davey25]

Thanks guys ..I did find a 2bbl intake but I believe it's off a yj..I'm sure there are issues with this

 

[davey25]

Ok so it's a 2bbl off a 81 cj apparently 1 piece aluminum..will this directly work to replace my 78 1 bbl cast 2 piece?

 

[rufus1138]

78-81 i would think will be kinda close, but there were a lot of things going on in those years with epa stuff that could throw off the usability of the manifold. if you dont have the same systems i would think the adapter would cause less trouble than potential losses from the unknown factors with the 2brl manifold.

 

[IOPort51]

I believe it will work, same head and the manifold didn't change much until it became injected. you will need exhaust too or a header.

If you think about this hard enough you will start to see the benefits of putting a kit in the 1bbl and getting stuff together for a 4.0 head swap with MC2100. This gives you just about 40 hp, I saw the readout from the dyno.

 

[davey25]

What did you mean by kit in the one bbl..dong the head ,header , and intake I'm assuming..I'm was thinking that as well..was just looking at getting the mc2100 on for now and then possibly going the v8 route instead of messing with the 6..my old CJ5 had a nice 360 in it and I loved it

 

[rufus1138]

ive been agonizing over the v8 thing davey and i would suggest sticking with the i6 if youre going to spend any time on the trails, the 6 will give you more torque at wheeling rpm ranges 1200-1800 ish, the 4.0 strokers and the v8's have more torque but they make it at 4-5k as you achieve bigger and bigger numbers.

it gets so that when you're doing that much work (looking at physics stuff here, watts not hp) it takes such a huge ammount of energy that you just have to have more air and more fuel to produce the btu's required to make the power needed, at that point it would take a physically huge motor to get the rpms back down to trail usable levels, great in the mud bog but useless for the rocks and hills. unless you want to build a crawler and gear things way way down i would stick with the 6's since they have a nice initial torque peak right off of idle.

 

[IOPort51]

What did you mean by kit in the one bbl..dong the head ,header , and intake I'm assuming..I'm was thinking that as well..was just looking at getting the mc2100 on for now and then possibly going the v8 route instead of messing with the 6..my old CJ5 had a nice 360 in it and I loved it

Kit: rebuild kit.

Carbs are a lot easier to rebuild than most people think and you get to say cool stuff like "It's a lot smoother since I rebuilt the carb" and "Then I rebuilt the carb". that 1bbl is a walk in the park and will be good practice for the MC2100/2150. The 2100 is even easier to rebuild than the carter.