The Mustang Chronicles: Carburetion

 For decades, carburetors were the primary devices for mixing fuel and air at a ratio to maximize combustion in gasoline powered engines.  These devices are simple in theory - they used the flow of air to regulate the metering of fuel, creating an ignitable vapor to generate power.  Over time, they became more complex to provide increased power and meet ever increasing emissions regulations.  With those changes, they gained a reputation of being clunky, inefficient, and unreliable.  This reputation is undeserved in most cases.  Carburetors have been used on everything from lawnmowers to large aircraft and are still used for many applications today. 

(Carter YFA one barrel carburetor)

The 1965 to 1967 six cylinder Mustangs originally came with the Autolite 1100 carburetor, as did most Fords with the Thriftpower six.  The Autolite 1100 is a one barrel carburetor developed by Ford as a replacement for the Holley 1904 and 1940.  It included an automatic, hot air choke and a spark control valve to manage ignition timing.  A common upgrade for these engines is to swap out the one barrel carburetors with two barrel units, and replace the Load-O-Matic distributor with a Duraspark or DUI/HEI.  This conversion can be done using an adapter for the Thriftpower's Log Head intake manifold, or by modifying the intake to accept a two barrel carburetor.  

Switching to a two barrel carburetor provides more horsepower by increasing the volume of fuel/air, which is measured in cubic feet per minute (CFM).  Increased CFM volume equates to more power through larger displacement, either due to the size of the engine, or by increasing the engine's speed, measured in revolutions per minute (RPM).  

But there is more to the math than just increasing CFM volume.  You also have to consider volumetric efficiency (VE), which is defined as the ratio of the mass density of the air-fuel mixture drawn into the cylinder at atmospheric pressure, to the mass density of the same volume of air in the intake manifold.  Or in plain English, you can't shove more gas into an engine than it can expel as exhaust.  That's why bolting a Holley 750 Double Pumper on the Thriftpower six is the automotive equivalent of the Milk Gallon Challenge.  

I'm more worried about drivability than power.  I want better street performance from a torquey engine with good throttle response.  The engine is basically stock, with the original camshaft, pistons, crankshaft, and exhaust, so I'm not going to get much benefit from a two barrel carburetor conversion.  

A better choice is to replace the Autolite 1100 with another one barrel carburetor and upgrade to the Duraspark or DUI/HEI distributor.  Ironically, many people swap out the Autolite 1100 for a Holley 1904, 1940 or "universal" one barrel carburetor.  Or, you can go with a Carter YF or YFA, like I did.  

I went with the Carter YFA for reliability and compatibility with my stock setup.  The YFA was used on a variety of Ford cars and trucks from the 1970s into the 1980s and bolts on with no modifications to the fuel line or throttle linkage.  It also provides the improvements in performance I'm looking for.  At some point in the future, I'll probably do a complete tear down on my engine, upgrade the camshaft, exhaust, and go to a two barrel carburetor.  But for now, I'm more interested in driving my Mustang than rebuilding it.          

Log Head Arithmetic

 The Ford 144/170/200 inline 6 is a simple, durable engine that is easy to work on.  It is a "cam in block" design, meaning the camshaft is inside the engine block, and the valves are actuated by pushrods.  From 1960 until 1983, it was the workhorse used in the majority of Ford's small and intermediate cars.  

The one shortcoming of the engine is the cylinder head - the intake manifold and cylinder head were cast as one piece for simplicity and to save on production costs.  Known as the Log Head, because the intake manifold looks like a small log with branches feeding the cylinders, it is a restrictive design and provides an uneven flow of the fuel/air mixture.  Early engines, made from 1960 to 1967, had the small log head.  Beginning in 1968, Ford changed the design of the cylinder head and increased the intake volume, which provided slightly better performance.  These engines were produced up until 1983, in cars like the Maverick/Comet, Granada/Monarch, Fairmont/Futura, and Mustang, and are referred to as large log heads.        

(The small log head from my 1965 Ford Mustang - the log is behind the valvetrain with pushrods)

The best way to increase performance on a pre-1968 six cylinder is to swap out the small log head for a large one.  From there, you can add a dual outlet exhaust header, Duraspark or DUI/HEI distributor, and a bigger carburetor.  You can also buy a 2 barrel carburetor adaptor or modify the intake manifold to accept a larger carburetor.  

(Large log head on the same engine - this head was cast in 1973)

Swapping out the cylinder head is straightforward, but not something to take on if you're a novice mechanic.  The Ford Six Performance Handbook provides detailed instructions on the steps involved, expert tips, and things to watch out for.  In addition to the advice in the book, here are some additional things to I learned:  

• Cylinder heads are all interchangeable for all years and displacements, but you will want to factor in combustion chamber sizes and compression ratios so you don't end up with too much or too little compression.    
• The cylinder head itself weighs about 65 pounds.  You will need help lifting the old one and installing the new one.  
• Ford changed the sensor for the temperature gauge in late 1965, so you will need a new temperature gauge if your original cylinder head dates before August of that year.  
• The carburetor spacer for the small log does not fit the large log - the bolt holes are about 1/2 inch further apart.  Additionally, the bore for the intake is about a 1/4 inch larger in diameter. This difference, in addition to the wrong carburetor gasket, will cause vacuum issues, leading to stumbling and hesitation.  
• If you go with a different carburetor, you may have to modify the linkage for the accelerator pedal.  The only carburetors I know that don't require this modification are the Carter YFA, Holley 1904/1940 and the Daytona or Universal carburetor. This modification is not difficult but you will need to purchase the V8 accelerator pedal and linkage.
• If you use a Duraspark or DUI/HEI distributor, you will need a larger gap for your spark plugs - from 32-35 to .45 or more.    

Done right, these modifications can increase power by 30% while costing less than $1,200.  The result is usable, every day performance that approaches the base V8 models of that era, making the car more lively and enjoyable while still maintaining a vintage feel.    

The Original Maverick was a "Hand-me-down"

 I hated the original Maverick... but was wrong to do so.  

Growing up in the 80's, the Maverick was a hand-me-down car.  It was as fashionable as a pair of hand-me-down Toughskin bell-bottoms from your older brother.  Cool cars of that era included coupes from the 60's, 80's Japanese imports, Firebirds, or two-door Cutlass Supremes.  Mavericks were the tragically unhip, back of the lot specials, and the kids that drove them would hide out until everyone else left school.  

The Ford Maverick replaced the Falcon in 1970.  It had the Falcon's hand-me-down platform, which dated back to 1960.  Engine choices were also handed down from the Falcon, including the 170/200/250 Thriftpower 6 and the 302 Windsor V8.  But the Maverick sold well and compared favorably to its contemporaries in the compact/import category.  It also wasn't a bad looking car either.  Early examples of the coupe had clean lines with classic long hood/short deck proportions.  I think the car even looks a little bit like a Ferrari 250 Lusso, which may have been intentional on Henry Ford IIs part, since he looked for every opportunity to stick it to il Commendatore. 

Viewed without malice or my 80's teenage New Wave and synth pop/post-modern cynicism, I've realized the original Maverick was a good car for its time.  A cheap, practical appliance that met the 1973 Oil Crisis, and ever changing pollution and safety regulations.  This year Ford is launching a new Maverick, and while the new one is a truck that offers a hybrid drivetrain, it is also a car for it's time.      

Regardless of what form vehicles take in the future, whether they are cars, trucks, or crossovers powered by hydrocarbons, hydrogen, electricity, or nuclear fusion, we will still need cheap cars.  Vehicles that are reliable, practical appliances, ones that eventually become hand-me-downs, even tragically unhip ones, sitting in the back of high school parking lots.

Mustang Chronicles: Gathering Parts

My simple job to replace a thermostat on my 1965 Mustang turned into this: 

(Ford 200 I6 engine block with new gasket before cylinder head install)

I broke a bolt off in the original cylinder head housing and had to drill it out.  My amateurish attempts to rethread the hole with an old tap and die set proved fruitless, leaving me stuck somewhere between my propensity to optimistically dive headlong into a project, and the limits of my skills.  So it seemed like a good idea to double down on optimism and take the opportunity to do some engine upgrades.   

The biggest shortcoming of the early six-cylinder Mustangs is the design of the intake manifold, which is cast as part of the cylinder head.  Ford decided they could save real money that way, but it results in an engine that breathes like a hamster with emphysema.  In 1968 Ford enlarged and improved the intake manifold and added larger valves in 1977.  The intake manifold looks a bit like a log, so pre-1968 heads are known as "small logs" and the 1968 and newer ones are "large logs".  Production of the engine spanned from 1960 to 1983 and it was used in just about all of Fords smaller/economy vehicles. 

(Remanufactured "large log" cylinder head from a 1973 Maverick)

The Ford 144/170/200 inline 6 will never be in the same league as the Toyota 2JZ or BMW N54 for performance tuning.  In various guises it makes between 90-120 gross horsepower.  But it's a stout engine, and it's possible to increase power output by 30-50% fairly easily and cheaply.  

In my case, it was cheaper to buy a large log cylinder head than have my old one rebuilt.  From there, I decided to also upgrade the carburetor and distributor with the goal of making 20-30 more horsepower.  Here are the details for my build:

• Remanufactured 69-79 Ford 3.3L 200ci L6 w/ 1 3/4" Carb Throat C9/D3/D5/D7 Cylinder Head from Allied Motor Parts. This head came from a 1973 Ford Maverick, but has the larger intake valves.  All Allied does is cylinder heads and they ship nationwide.    

• New Carter YFA 1 barrel carburetor from Mike's Carburetor Parts.  Mike's specializes in carburetors and has a lot of great technical and troubleshooting articles.  They do quality work and are made in the USA.  There are lots of options for carburetor upgrades on the Ford inline sixes, including two barrels using an adapter or modified cylinder head.  This article on Classic Inlines provides a wealth of options and information.  I chose the Carter YFA for the following reasons:

• I wanted something that would work with a "stock" engine, provide good low end torque and drivability on the street, and be reliable and easy to maintain.    

• I am not ready to modify the intake for a two barrel, or do a performance build on my engine.  I also didn't think a two barrel adaptor would provide better performance than the Carter 1 barrel, and I'd lose some of the drivability. 

• The Carter YFA was the standard carburetor for 1969 and 1970 inline 6 engines and a good match for the larger log head.  It was also standard on Ford's 240 and 300 cubic inch truck engines until Ford switched to fuel injection in the 1980s.     

• New Performance HEI Distributor - Besides the large log head, the biggest performance upgrade is to replace the Load-o-Matic distributor with a Duraspark or DUI distributor.  This HEI distributor got good reviews and was 1/2 to 1/3 the cost of either the Duraspark or DUI.  NOTE: You will need to replace the Load-o-Matic distributor if you swap out the Autolite 1100 carburetor because the LoM does not have a mechanical advance.  This article on Load-o-Matics from Classic Inlines will tell you everything you ever wanted to know.  .     

• New ARP Cylinder Head Studs from Vintage Inlines - these are overkill, and are 10 times stronger than the stock head bolts.  But after breaking bolts on several other parts of the engine, I felt the cost was good insurance, especially if I decide to tear down the engine again someday. 

I also bought the Ford Inline Six Performance Handbook.  This book is required reading if you want to rebuild and modify Ford inline six engines.  There is also a wealth of great information and knowledgeable people on the FordSix community website, who also maintain the links to the Classic Inlines tech info pages.  Finally, if you plan to work on one of these engines, please patronize Vintage Inlines, who are the go-to source for all things Ford inline 6.

Over the next few weeks, I plan to write about installing the cylinder head, setting up the carburetor and distributor, and any other tasks needed to get my Mustang back on the road.  

Mustang Chronicles: The Slippery Slope of Car Repair

 

What started as a 15 minute repair has turned into a downward spiral.  The Mustang started overheating, so I went to my local auto parts store and bought a new thermostat, temperature sensor, and coolant flush kit for about $30.  I about had it all back together, but snapped one of the new bolts, as I was tightening it with a torque wrench.  The bolt broke almost flush with the cylinder head, making it impossible to remove with vice grips.  

Broken bolts are a fact of life when working on an old car, and the early Mustangs seem especially prone to breaking bolts on the thermostat housing and exhaust manifold.  I ended up removing the radiator and drilling out the broken bolt, thinking I could clean out the threads in the cylinder head with a tap and die set.  

Unfortunately, I could not clean out the threads, or may have stripped them.  In any case, I knew I had more broken bolts ahead of me, because I was planning on replacing the cracked exhaust manifold, which also bolts on to the cylinder head.  My plan was now to removed the exhaust manifold and then send the cylinder head out to be reconditioned.  

That put me on the slippery slope of car repair, the one where you start with the intentions of doing a small repair job, only to slide down into the abyss of a full on rebuild.  I found a good engine shop, which quoted me about $400 to redo the cylinder head.  This would mean the Mustang would have the top half of the engine rebuilt, while leaving the pistons, bearings, camshaft, and crank untouched and original to a 56 year old car.  Should I do a full engine rebuild while I'm at it?  Do I leave the engine stock, or make some modifications to improve performance?  In addition to the engine itself, should I upgrade the carburetor and ignition?  How far do I want to go?  

Sometimes deciding what to do can be harder than actually doing it.  

 

Yeah, It’s Got a Six

“Hey, is that a ‘65 Mustang?  What-cha got under the hood?”

Those are the most common questions I get when I’m out in my Mustang. Most people don’t care when I tell them the car has a six cylinder engine, but a good number of people seem disappointed.  

Known as the Thriftpower or Falcon 6, the engine displaces 200 cubic inches (or 3.3 liters) and produces 120 horsepower and 200 lb. feet of torque. It offers acceptable performance with good drivability - so much so that the engine was used into the 1980s and powered in a variety of Fox body vehicles, including the early 3rd generation Mustang.

For people looking for more power there are a number of options including swapping out the one barrel Autolite 1100 carburetor for any variety of two barrel options or fuel injection.  Additionally, there are a range of exhaust headers, electronic ignition, cams and cylinder head modifications. Choices range from mild improvements for daily driveability, all the way to wild options like an Offy tri-carb setup and turbocharging.  

Early on, the six cylinder Mustang got an undeserved reputation as a “secretary’s” car.  But a Mustang with a six cylinder and manual transmission compares very favorably to many European cars of the same era.  Look at the performance specs for the Austin Healy 3000, Porsche 356C, or similar 2 + 2 coupes - the Mustang is either within striking distance, or puts up better numbers.

Best of all, a first generation, six cylinder Mustang has balance.  It is a throwback that provides equal doses of fun and practicality.  You can drive it daily and it is rewarding to drive across town on errands or cross country. You can work on it with a basic set of tools and a general understanding of auto mechanics. It can be your weekend car, or your only car.  It is approachable, doesn’t ask for much, but in return gives a purely analog driving experience.  

There are faster cars.  There are better cars, with more of everything.  But there are few cars that convey the joy of unbridled youth, of turning 16 and getting your license, and hitting the road on a spring day, with the windows down and the radio on.     

$15,000 Question: Ford Mustang

Back in junior high, my friends and I used to hang out at the local QuickTrip and play video games.  We'd save our lunch money or pool nickles and dimes and exchange them for quarters just to play Joust or Dragon's Quest.  Occasionally there was enough money left over for a pack of Now & Laters to split before walking home.  Usually there were one of two managers who worked afternoons at QT.  One was middle aged, sporting a wicked comb-over and generally grumpy towards us kids.  The other was in his early 20's, and to our 13 year old way of thinking, really cool.    

Part of what made him cool was he drove a Mustang, a maroon 1983 GT.

Few cars offer the combination of performance, heritage, and value of the Ford Mustang.  Now entering its 50th model year, the Mustang has been everywhere and owned by a larger cross section of people than just about any car in America.  It is an icon, one you can buy in just about any flavor for $15,000.



Mustangs come in many varieties--coupes or convertibles, 4 or 6 cylinder economy specials, V8 powered GTs, or performance versions like the Shelby and Mustang SVT Cobra.  There are even several tuner versions of the Mustang built by Saleen and Rousch, which include everything from body kits to fire breathing engines producing 700 horsepower or more.  Ford also built a Mustang SVO in the 1980's, which offered the same level of performance as the 5.0 V8 from a 2.3 liter turbocharged 4 cylinder engine.  The SVO was only made for 2-3 years, but paved the way for other specially tuned, factory Mustangs.



About the only misstep in the Mustang's history was the 1974-78 Mustang II.  Built on a Pinto chassis, the Mustang II was arguably the right car during the OPEC Oil Crisis and sold in record numbers.  But it's largely overlooked today by Mustang enthusiasts and panned by contemporary automobile publications.




My personal favorite Mustang is the Bullitt, a tribute car to the 1968 Steve McQueen movie of the same name.  To me, there's just something right about the understated car in Dark Highland Green paint with Torq Thrust wheels and a rumbling V8.

Mustang Cool

Mustangs are cool. They are one of the most legendary and enduring GT cars of all time. Yes, there were the neutered Mustang IIs of the mid-seventies and there's always been something a little blue collar about them. They don't have the breeding or sophistication of a Jaguar, Ferrari, or James Bond's Aston Martin. And you won't see one parked on the lawn at Pebble Beach next to a Talbot-Lago or some other over-restored rare bird.

But then Mustang owners wouldn't park their cars on the lawn. They'd farm it like a NASCAR driver on the infield at Daytona.

Cool. There's a reason why Memphis Raines' unicorn was a modified 1967 Shelby GT500 named Eleanor. Even James Bond drove one in "Diamonds Are Forever". But to me, the coolest one was the 1968 Highland Park Green example Steve McQueen drove in "Bullitt".

The original Bullitt Mustang was a basic, stripped down street machine with Torq-Thrust wheels. It prowled the streets of San Francisco with a 390 cubic inch V8 soundtrack. There were two cars built for the movie. One was supposedly destroyed during filming and the other is hidden away somewhere by a reclusive owner who makes JD Salinger look like Donald Trump.

In 2001 and again in 2008/2009, Ford produced a limited edition Bullitt Mustang to commemorate the movie. The new Bullitt Mustangs share the stripped down look of the original. They aren't the fastest or the best handling, or even the most collectible version. They don't have the 390 cubic inch engine or the legendary 5.0, but they are by far my favorite.

But no matter what version, the Mustang is cool. It has that It factor. Like a pair of Ray-Bans, jeans or Classic Rock there is an honest, American quality to them. Unlike some of the more expensive and pretentious GT cars, you don't have to put on airs to own one. You just drive it.

The Law of Depreciation

The law of deprecation is a car enthusiast's best friend. Cars that were $50, $60, even $100 grand ten years ago can be had for pennies on the dollar today.

I was reminded of this fact recently while browsing car ads online and realized there are a number of 1997-2000 Porsche Boxsters for sale below $10,000. Ironically, one of my favorite affordable Porsches, the 944, is appreciating towards that amount. So today you can have your pick--Boxster or 944 for the same money.

I know I'd take the Boxster. As much as I love the 944 for its mix of performance, handling, practicality and reliability, the Boxster includes all those traits and has Porsche's iconic flat-6 engine mounted mid-ship.

But it's not just Porsches that experience the phenomenon of depreciation. Just about any car hits its low value when it reaches 10-15 years old. In the 1970s, you could pick up a V12 Ferrari or Jaguar E-Type for the cost of a new Ford Pinto. In the 1980s and early 1990s, muscle cars and 1960s Corvettes were cheap. Now all of these cars are approaching the price of a three bedroom house, or far more in some cases.

Today you can find all kinds of bargains as well. The Porsche 928 and BMW 8 series are in the same price range as the Boxster, as are the Jaguar XJ and XK8. Or if you like American iron, you can pick up a C4 or C5 Corvette, Mustang Cobra, or Camaro Z28 for the same money.

The downside is as the Romans said, "caveat emptor"--buyer beware. All of these cars are at least ten years old and have close to 100,000 miles on them. They may have been lovingly cared for like someone's pet or abused like a Taliban donkey. And you won't know which without taking it to a good mechanic and spending several hundred dollars on a thorough inspection.

We also don't know if these cars will ever appreciate in value, becoming valuable collectors items. Certainly they have the potential, but for now, they should just be cared for and enjoyed.