How to Rebuild a Carburetor: Quadrajet 4 Barrel

Today on muscle car, we're breaking down the quadrajet, find out how to rebuild one the right way and why you'd want to revamp your garage floor on a budget and take a ride in Chevy's luxury muscle car.

Hey, welcome to Muscle car. They're probably the most made fun of parts ever used. If you got a GM muscle car, chances are, it probably came with one. Hey, quadrajet, these carburetors, they've gotten a bad rap for a lot of years. They've been called Leaky Unreliable, low performance quadra

junks. And today we're gonna show you guys why you shouldn't believe all the negative hype

Q jets. Well, they're capable of a lot of horsepower and they're really not as complicated as you think. If you're doing a stock R

on your GM, you'll probably be dealing with one. So we'll show you the right way to get one purring like a kitten and roaring like a lion. And

the most common type of performance carburetor is probably the Haley. Now, Haley and most other carbs use what's known as a square board design. That means that the primaries and the Secondaries are the same size.

Now, quadrajet, they use a design that's unlike any other. They use smaller primaries to meet emission standards and give you better gas mileage.

But huge secondaries to deliver the kind of performance that muscle car enthusiast demand

and get this a bone stock Q jet. They can give you up to 800 CFM.

There's more than one style quadrajet, Pontiac Buick and Os use the straight inland. While Chevrolet

used the 90 degree style, the late model cars are equipped with a throttle position sensor and a mixture control,

Iino,

the amount of emissions equipment and even the cars options like AC or cruise control can even make a difference.

The models that came on early big blocks used a bigger board, therefore, they're more desirable and you can tell this carburetor is apart by the bump inside the primary bore.

Now, the best way to tell which carburetor you have is by looking at the stamping number on the internet. So why don't they have such a bad reputation? If you've got one that's leaky or unreliable, it could be suffering from a bad rebuilt or just simply worn out. A lot of people assume that since it's a stock carburetor, that it's low performance, but that's just not true.

Now, we already told you guys that these things are capable of flowing up to 800 CFM and a properly rebuilt in two quad

jet. What may just surprise you as far as being complicated goes, it's probably just the outward appearance that has a tendency to intimidate people. Now, honestly, it's not the prettiest carburetor out there. But once you know, the basics, they're really no more complicated than any other car

when tearing down for a rebuild, first, remove all the external parts, fuel inlet choke, pull off idle, stop, solenoid and choke thermostat

when tapping out the roll pin for the accelerator pump lever, be sure to leave a little room behind the pin.

This will make it much easier to reinstall.

Next, remove the choke flap lever, disassemble the top plate from the main body, remove all nine screws including the two inside the primary board and carefully pry it off. If yours has been sitting around as long as this one has, you may wanna watch out for critters inside.

Now you can completely disassemble the main body.

Finally remove the base plate from the main body, remove the two retaining screws, the air fuel mixture screws, then pry it off.

Hang on to the gasket for now. We'll tell you why. Later,

the base plate, main body and top plate are all ready to be clean. So I'm gonna give it a bath while we're going to break.

But when we get back, we're gonna continue this Q jet makeover.

Hey, welcome back. I soaked our Quad Jet for over an hour, scrubbed it with a brush, wrenched it out, blew it off with some air to give these old parts that stock look, I'm gonna give the top plate and the main body a quick coat of this Eastwood carb renew.

This paint is designed for the outside of the carb only. So try to keep as much off the inside as possible

while we wait for the paint to dry. I'm gonna get working on the base plate. Now, one of the main things that can really cause problems with a Q jet is a worn primary shaft. Now, it's real commonly overlooked during the rebuild. I'll tell you it can make tuning one of these things just about impossible. Now, we're gonna repair this one with a bushing kit, but first I need to disassemble it and clean it by blasting it.

It's a good idea to label the flaps. They are side specific and you don't want to get them mixed up

with the flaps removed the throttle shafts slide right out.

I'm given a base plate a quick blasting before reassembling a wire brush and some elbow grease will work fine too.

Next, I'll drill out the throttle shop boards to make room for the repair bushings.

Now, the idea here is to only drill it as far as the bushing is gonna set in there that way you have a lip that'll prevent that bushing from falling all the way through and ended up in there against your throttle blades. That's what that piece of tape is there for. It's a depth guide.

I'm using a brass hammer here to keep from damaging the bushings like a steel hammer mite.

Some WD 40 on, some 1000 grit smooths away any left over funk

with everything cleaned up. The shaft can slide back in place along with the fast idle levers in spring.

Now, with the bushings installed, you can see that took up all the slack out of our shaft. So we don't have to worry about a vacuum leak there anymore. The next thing to check for is to make sure that on wide open throttle, your blades are sitting to 90.

That looks good.

Another common problem of the quadri jets are the leaking bottom plugs. It's not that hard of a repair. Some simple homemade plugs and some epoxy in a little bit of time, get it fixed. No problem.

First drill out the old plugs, making sure not to go too deep.

Tap out the hose with a bottoming tap and then mix up some epoxy.

I

already made a pair of plugs by chopping up some half inch bolts.

A quick dip in the epoxy will seal the threads.

A dab on the top, seals the deal.

Once our epoxy drives, we can assemble our main body to the base plate. Now, always save your old gaskets because carburetor kits usually come with an assortment. Try to keep them in one piece that way. It's a lot easier to match them up.

That's it.

This is the easy part. Just two screws. Attached the base plate back to the main body. I'm taking some 1000 grip to the pump and power fiston boards to remove any imperfections.

Now, ready to install the primary jets. I like to replace these when doing a rebuild because just like the throttle shaft they're probably worn also.

Now they come in a lot of different sizes, but Elder

Rocks calibration kit. It's got a big assortment. You won't know what size you need until you get into the carburetor. But doesn't matter which one you have this kit, it's got you covered.

After installing the jets. I'm using an old check ball and a punch to reform the seat before installing the new one.

One of the performance upgrades you can do to help out an old quadrajet is to simply swap out the needle and seat assembly with a high flow unit like the one supplied in our calibration kit. What this does is helps keep the carburetor from running out of fuel at wide open throttle

when doing a rebuild. I always like to swap out the float for a new one. Sometimes it's easy to tell when they're bad other times, not so much. And for about seven bucks, that's some pretty cheap insurance.

Once the new float is in place, I need to set the level. This kid includes a chart showing what the level should be for your model. But just by bending the arm,

it's very important to get an accurate level or you're just wasting your time.

Next, the power valve and primary metering rods drop in

and the floats, flash guard and gasket go on

another performance upgrade for the quadrajet is either to swap out or simply shorten the accelerator pump. What this does is it increases the pump volume during quick movement of the throttle.

These brass tubes have been known to fall out so I'm keeping them in place with a few light taps of a hammer,

use lock tight on the flat screws because you don't want them to back out, fall through the car and wind up inside your engine

for the final assembly, reattach the top plate and all the external components you remove on disassembly.

So that's one way to spruce up an old quadrajet. This was a stock rebuild with a couple of exceptions, but there's plenty of performance parts available out there if you need to go more in that direction.

So I'm gonna go both this on my old buick Gs, try it out, but stay tuned. There's a lot more moar

coming up

up next, personal luxury car or muscle car with this Chevy. You don't have to choose

today's flashback. A 1970 Monte Carlo, Ss

Monte Carlo for 1970.

The new one from Chevrolet at

a Chevrolet price.

The new Monte Carlo was shown here with uh

all other cars in its field.

The Monte Carlo really was one of a kind when it debuted in 1970.

Personal luxury cars like the Grand Prix and Thunderbird were the hot item.

The one thing you couldn't get in those rides was some real muscle. This luxury car had plenty of that to go around. But when you turn it into a super sport

first, you got one of Chevy's biggest and baddest engines.

The 360 horsepower turbo jet 454

it cranked out a whopping 500 pound feet of torque giving it plenty of giddy up

to handle the extra power. The suspension was beefed up along with the rubber GSE

wide ovals wrapped around 15 by seven inch wheels. Turbo Hydrotic transmission was mandatory with the SS package.

You also got dual chrome tipped exhaust with half inch larger pipe plus a super lip load leveling system which automatically balanced the car when he had friends riding in the back seat,

ss markings were discreet with small badges only on the rocker P.

This money is also loaded with a bunch of extras like a sports steering wheel stradle bucket seats, a gauge cluster with attack remote control sport mirror and rally wheels.

Since it was a luxury car, it had things like concealed wipers, higher quality nylon seats, bow wood trim and lots of soundproofing material

giving it a curb weight of over two tons.

The Monte Carlo was dreamed up a Chevy's version of the redesigned 69 Grand Prix

using the Chevelle 116 inch wheelbase as its starting point, the firewall was moved back and the nose extended, which resulted in the longest hood ever on a Chevrolet nearly 6 ft

with the engine sitting further back. It was well suited for NASCAR

which had joined in 71

styling was based on the Cadillac, El Dorado but used more muscular fenders with beveled edges. It shared the same windshield, rear window and deck lit as the Chevelle but had wider sea pillars and a slightly larger rear end,

single headlights replaced the Chevelle dual setup. And the egg crate grill had a distinctive Monte Carlo Crest in the center.

Only the 7071 models had the year embossed Roman numerals.

The car debuted in September of 1969 and the public loved it. By the end of the following year, 146,000 were on the rope outselling its ravel the T bird by 3 to 1 margin.

Only about 3800 got the SS treatment though probably due to sticker shop,

Monte started out at 3100 bucks but a fully loaded one like this would jack the price up to over five grand

1000. More than

a Chevelle Ss

Super Sports didn't fare

any better in 71 with less than 2000 sold. So Chevy deleted the option in 72.

The muscle car air was winding down and Chevy felt the package clashed with the car's luxury image. It would be 11 years before the SS returned to breathe new life into the brand and help put Montes at the top of the heap on the NASCAR Circuit.

The 1970 Monte Carlo Ss stands out today as a car that combined luxury and muscle into one impressive package

coming up. How to transform your garage floor in just a weekend.

Hey guys, welcome back. You know, they say a man's home is his castle. If you're a car guy, your garage is your castle. I don't care how many cool posters and old license plates they hang on the wall. If the floor looks bad, the whole place is gonna look bad. Now you can call a pro to come in and code it for you, but that can run into some big bucks. So I'm gonna show you how to get a floor like this and still have enough money left over to park something on it.

Build on a budget muscle car projects that save you time and money.

Now, coating in a cement floor yourself is actually a lot cheaper than you might think.

This epoxy floor coating from you coat, it will handle a 2.5 car garage and run you less than 250 bucks. And once you have all the prep work done, you're gonna have a good looking long lasting floor in less than a weekend

and we had you code it on the shop floor for years and it's held up fantastic paint mixing room. On the other hand, what's never been coated? It's looking pretty sad. So I'm going to seal it all up. Get it looking better than new.

Prepping out. The floor is extremely important. Start by sweeping or vacuuming up all the dirt.

Next check to see if your concrete has a sealer. Pour straight Mura acid on the floor. If nothing happens, you'll need to strip off the ceiling before you go any further. If it bubbles, you can move on to the next step. Spray or hose it down with plain water and look for any beating.

It's beating up right there. It's gonna have to be cleaned. Beating means contamination thoroughly clean these spots with a degreaser and a brush. Now, once it's clean, neutralize the alkalinity of the floor with the Mura

acid solution,

be sure to wear protection and keep the area well ventilated. A

thorough rinsing comes next. A little baking soda in the water helps neutralize the acid go over the floor two or three times leaving a wet but with no puddles or standing water,

apply the epoxy bond coat to the wet concrete using a W pattern. Make sure the concrete stays wet during application to ensure good penetration.

Well, that's it. All we have to do now is let this dry for about four or six hours. But on a second coat,

this coat goes on just like the first. Remember you have a 72 hour window or you'll be sanding between coats.

Hey, check it out, man. Our new floor looks awesome. Plus it's gonna last for years. Not to mention the fact. Should make cleaning up those little spills a whole lot easier. I'm gonna try to not put that theory to the test and mix up some paint for our next project. But for this week we're out of time. So until next time we're out of here.