Counting carbs

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Was trying to figure out why my fox sometimes wants to cough when I try to open it up especially in second and really looking at all three carbs it came with. The two Edelbrock one are identical. Stamped 8867 unless I'm blind. Doors this suggest at one time the car was running double carbs? That's a thing, right?

Carburetors are the superior form of fuel delivery as noted by the purity of combustion without electronic assistance

>>16011392
>three carbs
Wew

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On really looking at it the Holley seems like a much much better carb with way bigger bowls, metal fuel lines and more adjustments.

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The Holley is stamped 4778. Before today I had planned to just rebuild it but now that I notice the Edelbrocks are literally identical it makes me wonder about double carbing but I know literally nothing about it as I only just now realized it might be a possibility.

So yeah after spraying is down real good with carb cleaner... Did you know you get age checked to buy carb cleaner at Walmart? WTF are kids doing with carb cleaner? I take it for a test drive to see if it's improved. I was driving it last night and it had been hard to start from sitting - I'm always worried I'm going to stall it then kill the battery before I get it going - but it almost never gives me that coughing in 2nd gear at night which is weird. The drive was going good until I was on my home lap and it died twice at or immediately after traffic lights. It started back up and I got it into my neighborhood but then climbing the hill, not even under hard acceleration it just coughed and died and it made a funny pathetic sound and puffed some smoke out from under the hood. Remaining calm, I just tried to start it back up and got an awesome backfire and a bunch more white smoke out from under the hood. N

ow, in modern cars this is cause for alarm but I reminded myself that my baby isn't some pussy turbocharged i4 that kills itself if all its ducks aren't in a row. There was no horrible grinding popping clanking or banging when it turned over so I calmly just coasted backward and off the road, popped the hood and took a look...

Yep, that was an engine all right. Still all there, no smoke coming from any gaskets just up and out of the carb once I took the air filter back off... No water in the oil or anything horrible, no boiling coolant.

Then I remembered the PO telling me about how the pretty little ignition coil mounted to the firewall just like it belonged there failed him once on the highway and needed to cool down so he'd put the big fat performance coil back on and it had been just wired to some holes in front of the other one. I reach in to feel if it's very, very hot and realize it's slipped down and is sitting directly on the manifold. I'd wondered why someone had heat wrap only on the passenger side manifold and now I know. It's a good thing too because if it hadn't been wrapped I'm sure I'd be buying a new coil right now.

So just as I'm realizing this little chestnut, the first car to have come by pulls up next to me and I'm opening my mouth for my "got it under control" brush off but of course, it's the blonde girl with the big tits /o/ loves from the bikini pic of her with my truck.

She wasn't even on her way to my place, rather off on god only knows what misadventure. It's hard to be cool when you're broken down by the side of the road but I told her what I suspected was going on. She offered to "push me up the hill". Apparently in her hot blonde brain bumper to bumper pushing a car up a hill is a reasonable thing to do - and this is a pretty steep hill, too.

"No, it's cool" and she was on her way. This conversation had given the coil enough time to cool down to where I could reasonably touch it so I got back in, turned it over a few times with no throttle to clear out any flood and it started right up. I was even on level enough ground to get the air filter back on with it out of gear and running and it didn't roll into the crick or nothin'

Got it to the garage and managed to snap a pic and send to her that it was fine now before she even got finished typing her check-up message to me.


It's nice to have a car that can go from blowing smoke to purring like a kitten in ten minutes flat. The only thing that would have made it easier was a beer and now I'm cautiously optimistic that relocating the coil somewhere cooler (and more secure) will solve my coughing issue. If it does, I'll be free to start thinking about what to do with these carbs - and about maybe installing a second hand nitrous kit. I see them for only like $200. I dunno if I'd even keep the tank full but it seems like something fun to install.

Jeez are there really no carb guys on right now?

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I love my carburetor

>>16011401
Yup. Hollys are some of the best downdraft carbs you can get. Nice clean venturis, no silly air doors, a modular design that is easy to work on and change.

The only crappy part is that the fuel level is above the bowl gaskets

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I currently fly carbureted piston helicopters and there's an interesting phenomenon associated with them. Since the way carbs work is by forcing air through a constriction to get the low pressure zone, the carb tends to freeze up since ice will form easily at low pressures. We use a little lever that uses muffler heat to warm up the carb and prevent the engine from choking. They also don't require a choke to startup unlike bikes which I don't understand yet.

>>16011587
I have a quadrajet on my 283 in my FJ40 right now.
Runs alright but not perfect, sometimes a sort of jerky puttering, usually in 3rd gear.

Would it be carb issue or ignition coil most likely?

>>16011392
Old corvettes and drag cars would run double 4-barrels but yours probably didnt. If your car came with spare carbs it's because most people know JACK SHIT about carbs and it theirs isn't working how they like they just buy another one.

>>16011492
are you sure your timing is set right

Is your carb and it's vacuum lines installed right

Cool story, sounds like quite an adventure.

Back in the day, no one ever really knew what they were doing with carbs. It was pretty much just run it rich, then make 1/4 mile passes and keep jetting it down until it started getting slower.

Nowadays, with even fewer people running carbs, about 1 in 100,000 people actually know how to work on them.

As far as

>Was trying to figure out why my fox sometimes wants to cough when I try to open it up especially in second and really looking at all three carbs it came with.

goes, most times it's caused by a power valve either too big or too small, or secondary jetting too big or too small. If you get it up to higher RPM and punch it and it goes fine, chances are the power valve is too big and you should step it down. If you try it at higher RPM and it still bogs, chances are it's too small and you should put a bigger one in.

Last I knew, a power valve was a type of diaphragm, and they liked to blow the fuck out if the engine backfired, so you may want to replace it anyway.

If you're using the Holley, order up a set of jets and some power valves of varying sizes. Set the timing as best you can, using the idle speed/vacuum method works fine if you don't have a timing light or timing marks. Check some plugs after driving around for a bit, see if you're looking rich or lean. Jet primary/secondary accordingly if you need to. If the plugs look fine, don't fuck with the jetting, just try changing the power valve up or down a size depending on the results of the higher RPM test.

Also, you done any tuning to it yet? I don't mean adding a sick nasty CAI and quadruple glasspacks, talking more along the lines of checking timing and setting the idle mixture screws. Both of those can help with responsiveness and are piss easy to do. Setting idle mixture screws and idle speed can also keep it from shutting off when you come to a stop, changing timing a bit could probably help too.

>>16011392
Foxbodys never came with dual carbs as far as I know

>>16011653
Yeah see this is the kind of info I was looking for. I have absolutely no idea how to do any of that lol. In another thread I was told that the fuel flow on the Edelbrocks has to be set internally by opening up the bowls and bending a little leg which sounds crazy to me. I'm guessing that big ass springy screw on the front is the idle screw but it doesn't die at idle once it's warm, rather on initial acceleration. I'm cautiously optimistic that the ignition coil getting too hot was to blame but I'd still like to understand more about the carbs. I'm getting the consensus that I'd be best off rebuilding the Holley rather than fucking around with some doyble-the-headache dual carb system at least for now. Fuel jets are what govern how much fuel can be sucked in from the bowls/richness right? I suppose I shouldn't assume that carb was once set up for this engine or even if it was that it was set up right.

Adjusting timing is done just by turning the distributor right? Timing lights aren't very expensive I don't think but like I said this coughing thing didn't happen when I was sitting still and the engine was first warming up. I can bring it to 5k and hold it there when it's still, it's only something that crops up after I've been driving it. I used to think it was from "slosh" on from forward Gs and/or turning and seeing how small the Edelbrock bowls are kind of doubled that theory down but I guess there's no guarantee it wasn't two separate issues with similar symptoms

>>16011695
There ain't nothing stock about this fox. You see that manifold?

This brings up another question. Considering I bought this thing cheap with no build records whatsoever is there any way to figure out how big a nos shot it could take short of pulling the head and looking at the pistons? You can peek in the valve covers and see nice pretty roller rockers and hear the cam but that all is hardly scientific. I realize that it's dumb to even think about that until I get it tuned perfectly NA but I like to daydream and damn are second hand nitrous kits cheap. My somewhat frightening guess is that they all come from people who shot a rod through their block with them.

>>16011727

Carbs can get kind of complicated in a hurry. You'd be better off researching how to tune them on your own.

99% of the time, people will buy a carb, drop it on a motor, and never touch it again. If you fuck with the carb you'll probably be the first ever person to do so with that carb.

The little leg you're talking about is probably the float arm thing. The floats control the fuel level of the carb, and the general mixture of the carb I believe. You can adjust them, and sometimes need to, though I can't remember under what circumstances specifically.

Cursory research seems to show that floats set overall fueling, independent of the jets, kind on a general, all-purpose basis. Read this. It'll probably help. http://forums.holley.com/entry.php?442-Float-And-Fuel-Level-Adjustments-On-Holley-Four-Barrel-Carburetors

The idle mixture screws can play a role in initial acceleration from a stop. Too rich or too lean at idle can affect the initial fuel once you get on the throttle - if you're too rich, you'll get richer and bog. Too lean and you'll be in the hole for fuel, and still bog. They're worth playing around with. Just turn them, little by little on both sides, in one way or another, until the idle speed is as high as you can get it without touching the idle adjustment screw. Then turn the idle down to where you want it. Very, very easy.

Jets essentially affect fuel flow at different air speeds. The primary jets are when you're just cruising around under light throttle, the secondary jets are for when you're at full throttle or higher RPM and the air flow opens the secondary flap. Primary jets would have an effect if you're just driving around and try to accelerate slowly and it bogs, secondary jets come into play higher in the RPM range, or when you suddenly flat foot it. When you slam the pedal down though, the power valve also shoots a bit of fuel into the carb to make up for the increased air flow.

>>16011760

Because of that power valve hitting, a lean secondary jet could be masked by an overly rich power valve - if the engine suddenly loses steam after it gets up and goes for a second, chances are it's more the secondaries to blame.

Adjusting timing is indeed done by turning the distributor. Hard starting can also be a timing related problem.

Timing lights are cheap, sure, but without timing marks on the balancer they're useless. You can't check timing without timing marks, which on an older car are usually worn off, or the pointer is missing, or the balancer has been replaced with something else with no marks, or they've been painted over, or all manner of other stupid crap.

Options at that point would be to find TDC and put your own marks on, or just use the idle/vacuum method, which works just fine. If you want finer adjustment, get a 0-60 timer app, go out and do passes. Change the timing only one way or another, set it at the amount where the car runs the fastest. Then play with fuel, doing the same if you don't have an O2 sensor.

I'd say the best place to start would be timing. After that, look into carbs more and start messing around with them. You have three. Don't fuck with at least one of them and you'll always have something to fall back on.

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>>16011760
>>16011777
So basically I should obviously not fuck with the Edelbrock that's on there and working right now and rebuild that Holley. The main things to fuck with on the carb are the idle air control and the jet sizes, which are swappable on that carb. I should also play around cautiously with the timing. If I get it running perfect with the Holley then maybe I can start thinking about what exactly double carbing might do for me and if I want to count on the Holley as my fallback and start tinkering with the Edelbrocks.

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lol check out this ring. It costs as much as the intake manifold it turns out I would need to buy.

I learned a new power word today

"dual quad"

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>muh dik

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>>16012097
only 2 carbs?

>>16012113
>>16012128
Still 8 barrels either way. Yours looks more expensive.

>>16011752
Do a compression check. Might want to check the ring gap as well, but that's basically it.

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>>16012128
notice no intake plenum
each port has its own carb. it only SEES one venturi. that makes for higher velocity of air.
in a normal manifold, the intake port thats sucking at the moment sucks from all 4 in a 4 barrel. meaning the air is going slower. see?

so by using no plenum people can get away with bigger cams, that means more rpm.

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>>16012142
yeah but there are pluses and minuses to them.
minus, well a lot
no vacuum for brakes, and no vacuum for the vacuum advance. look at it. kind of a big trade off?
The weber is a pretty barbarically simple carb.

>>16012154
Okay yeah I guess that makes sense but I already have 2 identical Edelbrock 4bbls so I'm kind of 4/5ths of the way already

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>>16012181
but for most people who dont need a fuck huge camshaft you can use a normal 4 barrel like a holley. if you have a tame enough cam you might even use a vacuum secondary.

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>>16012202
sell them on CL and get yours working right. if you cant tune one you have NO CHANCE of two

>>16012231
I have not yet begun to tune them

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I smoke
So does my car

>>16011653
Also if it's an older Holley he should upgrade to clear plastic sight plugs for the float bowls.

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>>16012444
you mean "it" right?
have a look at the factory chevy 302 that was used in trans am racing. it was 2 600's and was considered overkill for 7000 rpm at the time.

>>16011392
>my fox sometimes wants to cough when I try to open it up
That sort of thing is usually a lean condition. Tends to happen more when the engine is cold but if it's lean enough it'll do it at any time.

With the Edelbrocks you get the primary jets in the ballpark and then change the metering rods as necessary to trim the fuel. You change the metering rod springs to change the point where a power mixture would be introduced, much like changing a Holley power valve vacuum rating would.

In general Edelbrocks do fuel efficiency while Holley's do better at making power. Holley's have better parts availability though. At worst you can get some pieces at O'Reilly's and if you really learn the things you can raid regular carb kits for OEM applications for some stuff in a pinch.

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>>16012483
I have three. I love your authentic 4chinz style acerbic negativism and everything but you should really read the whole thread if you want to make your insults truly personal. I know, I know being a shitposter is a full time job these days with the newer, kinder radioactive moot especially on a relatively self-assured board like /o/ but keep at it. Maybe say something about forced induction or tell me my fox will never be as fast around the burgerking as a gt-r?

>>16012479
Good advice I will almost certainly do that. Would be nice to see inside it without having to take it apart and replace gaskets.

>>16012460
Neat! You can roll coal just like a VW. That's not a google image search result at all!

>>16012507
It really only happens when it's hot is the thing. I'm really leaning towards it being the coil but I still want to get hype about carbs at least enough to get motivated to rebuild the Holley. That bit about "making power" sounds good although I must agree that I've been amazed at the fuel economy it gets right now with the Edelbrock.I guess if I get both working I can switch out for long trips. I suppose the settings would be quite different for a dual quad application though.

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>>16012460
I don't have photoshop

>>16012554
>dual quads
Cool in it's own way. Never runs them myself though have thought about it. It is interesting to note the FE big-block types go to great lengths to find matching dual quad carbs but for driveability, not originality. Apparently the calibration of such carbs isn't quite off-the-shelf. How bad regular carbs in a dual-quad role are I have no idea. Can't be THAT bad I wouldn't think.

>>16011612
>don't require a choke to startup unlike bikes which I don't understand yet

Does it have remote mixture control? I know this was a thing on planes. Rather than restricting the air flow they just up the fuel level.

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They have their place. Not sure a SB Ford is the place though.

>>16012978
It was just the fact that two of them were identical right down to the model number that got my mind wandering on the possibility that they had been set up that way at one time but now that I see you definitely need a special intake manifold and no such intake manifold came with the car that it's unlikely - although they do seem like the sort of carbs that people do run in that application. I imagine that Holley could do everything I could possibly need it to though so I would probably be wiser to aim for tuning the Holley for performance and the Edelbrock much more conservatively for economy to swap in for longer trips. As I understand it cheater plates are universal too so I wouldn't have to choose even if I did end up putting a squirt on it.

>>16012978
What carbs are these? Nice regulators