Replacement Carburetors

[shadowsun]

So I've finally stumbled across the answer to all my remaining carburetor problems:

These are known problems for the stock carburetors and not much can be done about it.

So, with your help, I should like to compile a list of carburetors that will fit on the 3TC Engine with a minimal toolset (Since I'm stuck ~1100m from any even halfway minimal toolset - I'm rebuilding my carb with a socket wrench set and rustry screwdrivers here.) and not much fabbing of adapter plates, or that have adapters that are easily and fairly cheaply bought.

So far, I'm aware that a weber 32/36 DGEV (And the near-identical copy, a Holley 5200) fit on the car pretty easy. However, if I'm going to go to a junkyard and find these, it'll go alot faster if I know what kind of cars had these stock.

Also, what about re-jetting? Which ones would i need to re-jet, and which ones could I get away with out messing with too much?

Suggestions welcome, people. I'd like to see some responses instead of just stumbling around in the dark.

[Flashmn]

If I was in your shoes, I'd just stick with the stock carb, or get another one of them thats in working order.

[shadowsun]

Why is that? I've found alot of information that says the stock carb is basically shit, and if I'm going to have to replace it anyway is there any real reason not to replace it with a carb that will improve my gas mileage and power? Or does even changing to like a weber 32/36 DGEV require an engine rebuild?

Since I plan on rebuilding the engine in the next couple of months anyway, I'm not sure that would pose much of a problem, and I also plan on eventually rebuilding essentially the entire car.

Why? Because I find this stuff fun.

[Flashmn]

Stock carb will work just fine if you dont start to tune your engine, if you plan on keeping it stock. You say that you'd get better mileage with a weber, I'd say you'd get better mileage with a factory setup stock carb than an guestimate-adjusted weber.
Also one myth that I'm gonna clear up. You wont get both gasmileage and power, you'd get only one, because if you want mileage, you wont have so much power and vice versa. Power is made with gasoline, mileage with the lack thereof.
The stock carb isnt exactly that bad as people make it out to be.

[shadowsun]

Originally Posted by Flashmn

Stock carb will work just fine if you dont start to tune your engine, if you plan on keeping it stock. You say that you'd get better mileage with a weber, I'd say you'd get better mileage with a factory setup stock carb than an guestimate-adjusted weber.
Also one myth that I'm gonna clear up. You wont get both gasmileage and power, you'd get only one, because if you want mileage, you wont have so much power and vice versa. Power is made with gasoline, mileage with the lack thereof.
The stock carb isnt exactly that bad as people make it out to be.

I do plan on tuning the engine, and I've absolutely no desire to keep it stock. It's just too much fun to work on, even when I'm cussing at it.

I'm told that a big reason for the better gas mileage and power is because these carburetors (Mikuyi, Weber, Holley) atomize the fuel much better, resulting in a more efficient burn. In any case, I've had shit for luck in getting the carburetor to not run too rich, so far, although for all I know this is because of lack of knowledge rather then a totally shot carburetor. So any way to make it run not too rich is going to result in better gas mileage without a loss in power, since I'm already dumping in more gas then I burn, right?

<Edit: Although I suppose that if I had better airflow this problem would go away to some extent, with regards to richness. >

I've also been told that it is possible that my choke is frozen open, which is something I can't discount until I figure out how to check it out. One of the next steps I have to do before I work on the carb more is replace most of the lines it plugs into, because they are hella old and I'm having problems with them growing holes.

<Edit: I doubt the choke is frozen open. If this were so, the engine would have trouble starting (as I understand it right now) instead of catching and starting, today, in half a second. >

Knowledge is power. Applied knowledge is horsepower.

[Flashmn]

I'm told that a big reason for the better gas mileage and power is because these carburetors (Mikuyi, Weber, Holley) atomize the fuel much better, resulting in a more efficient burn. In any case, I've had shit for luck in getting the carburetor to not run too rich, so far, although for all I know this is because of lack of knowledge rather then a totally shot carburetor.

Well the mixture adjustment on the aisan carb is for idle mixture only, it affects also some of the off idle mixture, but not that much. Yeah, you've been told that eh? One things for sure, if you want to make power, then you wont get mileage like I said. Atomization has really miniscule effect on power output. If I had two carbs running peak performance otherwise similar, then the one that atomizes better would maybe produce slightly better power, but in reality, its not noticeable in any form, its more theoretical. But claiming that a carb will give you more hp and better mileage than stock is just a load of crap. Its either one, not both. My twin DCOE webers have horrible fuel consumption, but then again, its not what I was looking for.
Also another question, how do you know you're running rich? O2 meter? EGT? Exhaust gas analyzer. EGT and the exhaust gas analyzer are the only ones that I'd be tuning with, an O2 sensor gives you an idea of what it is, but its not accurate enough to tune on.

I've also been told that it is possible that my choke is frozen open, which is something I can't discount until I figure out how to check it out.

Easy to check, take off the airfilter, its the big plate that covers the venturi. No its probably not stuck open. Then again my Webers dont even have a choke. Nice to start it on a cold engine, few pumps of the acceleration jet and crank, and then drive off.

[shadowsun]

How do I know I'm running rich? I don't think I should be able to smell unburned gas from my car when driving down the road. And there's the flooding the engine problem I'm working around. All of this tells me way too much gas is getting in there.

[Flashmn]

How do I know I'm running rich? I don't think I should be able to smell unburned gas from my car when driving down the road

Well thats not a very good indicator of running rich.

[shadowsun]

add to that, observed on todays rather hot day:

Black, gassy smoke, dieselling, and so on.

Thought you shouldn't be able to smell unburned gas when doing 45mph

Also, I should add that the engine is flooding when I'm doing any speed, and rev the engine over 4kRPM very often.

If these aren't indications of running pig rich, what is?

[Flashmn]

Dieseling is usually a sign of running lean. Running lean will also increase your hydrocarbon emissions (unburnt gas) from your tailpipe. How do you know you're flooding?

[shadowsun]

I suppose the answer to this is going to make you laugh;

"Because when it floods, I have to wait about ten minutes for it to be able to start again. This is identical to when the float was stuck, and the shop told me it was flooding the engine. Since I have a huge increase in performance, the entire thing must be running too rich still. I'm also having the problem where 1 to 3 cylinders, as near as my ear can tell, quit working but then come back as the engine continues to turn over. Not to mention, if the car's stalling from leaning out, shouldn't it do it under heavy accelleration and cornering, and not when trying to idle?"

but that's essentially my reasoning. Am I really this far off? I know so little. I'm just a mostly dry sponge, trying to keep my car alive until I can soak up enough information to make it sing.

(concerning the shop: ) I can't discount the possibility that my assumption of their correctness was wrong; afterall, this particular mechanic forgot to put about four inches of my radiator back together and almost fried my engine.

But it was a Toyota dealership, and when I rebuilt the carb the float assy / valve and such were sticking.

I really wish I had what I need to break the superglued screws loose. Then I could get further in then just the air horn and give EVERYTHING a good thorough cleaning.

[Flashmn]

if the car's stalling from leaning out, shouldn't it do it under heavy accelleration and cornering, and not when trying to idle?"

Not really if the idle circuit is the one lean... plus when you pump the gas to accelerate it has an accelerator pump that injects fuel to the throat. It would mask alot of problems.

[shadowsun]

As i've stated before, the rod arm from the throttle assy. to the pump lever is disconnected.

So it can't really mask anything.

[Flashmn]

refreshen my memory, but has it been disconnected all the time?

[shadowsun]

It has been disconnected since long before I bought the car. In fact, it's been disconnected so long that the bottom of the pump chamber is covered with shellacing from the gas left in it so long. I wasn't able to get the check ring or bearing out of the bottom. I intend on giving it a very long squirt of carb cleaner before I reattatch it. I have to kludge something up to reattatch it, as well, since whatever was there to do that isn't there now.

Is it possible the car has been running lean for a long, long time and I'm only now learning enough to realize it?