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This one was used on a pretty wide variety of cars, but I had to include it because of the name. I mean, c’mon. How I could I not write a post about an automotive component with a name like that? It’s awesome.

Invented by a Briton, one Edgar de Normanville, and manufactured by automotive supplier Laycock Products, the unit basically consisted of a solenoid-activated planetary gearset residing between the standard manual transmission and driveshaft, offering a reduction in gear ratio at the driver’s command. At the press of a button or flip of a switch (depending on the car) in the cockpit, the overdrive would engage and lower the engine speed relative to the driveshaft, markedly improving fuel economy.

Advantages? Transmission development has always been pricey, and as fuel economy began to become a priority for automakers, the idea of a fuel-saving external add-on to an existing 3- or 4-speed manual transmission was an appealing one. Not only that, but the nature of the Laycock Overdrive meant that it could be engaged at any time, even in the lower gears, effectively doubling the number of ratios at a driver’s disposal. A 4-speed tranny became an 8-speed, for instance.

Downsides? Added complexity, mainly. The solenoid in particular could be finicky on higher mileage cars, and frequently the overdrive unit had its own fill and drain plug separate from the “main” transmission, requiring a unique maintenance interval. As all-in-one 5-speeds with integrated overdrive became de rigeur, the Laycock Overdrive faded from the scene.

I first learned about it from its presence on the Volvo M46 4-speed + overdrive transmission. Installed from the factory on Volvo 240s and later 740s, it’s one of only two manual transmissions (the proper 5-speed M47 being the other) available stateside for those of us interested in a bolt-in manual swap for a Volvo 200-, 700- or 900-series. Remarkably, up until the late ’80s, the Laycock Overdrive was fitted to a wide variety of cars, not just Volvos: Jaguars, MGs, Austin Healeys, Alpines and Triumphs, among others, were available with the unit. Not too shabby for an obscure bit of engineering with a funny name.

Editor’s note: This post is part of an ongoing series spotlighting obscure automotive engineering solutions. Read the other installments here:

• Opel’s Cam-In-Head Engine
• Nivomat Dampers
• The Desmodromic Valve
• Front-Engined AWD Systems
• Mercedes’ Monoblade Wiper
• Twincharging
• The Turbine Car
• The Sleeve Valve
• The Variable-Geometry Turbo
• The Hydraulic Cooling Fan
• Audi’s UFO Brakes

I love weird engineering. As much as I might be cursing on any given Sunday afternoon leaning over the engine bay of a car featuring said weird engineering, shaking my fist at the gods as I ask why the automaker couldn’t have assembled the car the “normal” way, I’ll always admire manufacturers who march to the beat of their own drum. Whether it’s an all-encompassing philosophy or a random decision here or there, automakers who deviate from conventional wisdom will always command my attention.

Today we embark on a new series of posts highlighting technical esoterica, or unique solutions to engineering challenges in the automotive world. Sometimes there are plausible justifications for off-the-beaten-path decisions automotive engineers make, but sometimes it seems like automakers just want to do things their own way for the sake of being different. Either way, let’s dive in.

The year was 1989. Audi was introducing its top-of-the-line Mercedes- and BMW-fighter, its V8. Built on a stretched version of its 100/200 mid-size chassis, Audi stuffed a brand new, all-aluminum, 3.6l, DOHC 32-valve V8 (oddly enough) under the hood, paired it with its first automatic quattro drivetrain and decked the whole car out in appropriately luxurious trappings. In spite of the added bulk over the run-of-the-mill 100/200, the big V8 moved the car along as a respectable clip. Braking prowess, however, was another area Audi wanted its new luxury flagship to have sporting credentials. But instead of simply giving the V8 larger front brakes, they decided to do something a bit different.

Constrained by a maximum wheel size of 15 inches, Audi enlarged the swept area of the brakes, and thus their potential stopping power, by “flipping” the caliper inside the disc, creating their “UFO” brakes, so called because of the resemblance of the disc carrier and its heat-dissipating holes to a stereotypical alien spacecraft:

This move allowed the diameter of the disc to fill the inside of the road wheel, without having to allow for a caliper positioned on the perimeter of the disc, as is the case with every other disc brake system.

Did it work? By all accounts, it did—when operating as designed, compared to “regular” disc brakes engineered to fit the same 15″ wheel diameter, the UFO brakes provided tremendous bite and resistance to fade. The system gave the V8 (and ’91 200 Turbo quattro, to which it was also fitted) braking capability commensurate with its accelerative abilities.

Did it have downsides? Most definitely. UFO brakes weren’t shared with any other automaker, and failed to benefit from economies of scale in manufacturing; replacement rotors and calipers are quite expensive. Improperly maintained, the rotors can warp; an often-prescribed “solution” involves multiple consecutive panic stops from highway speeds. Allegedly, this can straighten out the rotors and eliminate the shimmy. And perhaps the most significant bummer for those concerned about appearance, especially when exposed by thin-spoke aftermarket wheels, to the uninitiated UFO brakes have the decidedly downmarket appearance of steel wheels.

Regardless of its engineering justifications, disadvantages or even its benefits, Audi’s experiment with UFO brakes appeals for the simple reason that the automaker tried something different. Kudos to them.

Editor’s note: This post is part of an ongoing series spotlighting obscure automotive engineering solutions. Read the other installments here:

• Opel’s Cam-In-Head Engine
• Nivomat Dampers
• The Desmodromic Valve
• Front-Engined AWD Systems
• Mercedes’ Monoblade Wiper
• Twincharging
• The Turbine Car
• The Sleeve Valve
• The Variable-Geometry Turbo
• The Hydraulic Cooling Fan
• The Laycock de Normanville Overdrive

The Dell’Orto carburetor never achieved the popularity it deserved. Imagine a dual-barrel sidedraft carb that flows almost as well as the industry performance standard Weber, but is much more flexible and docile in real-world driving, and you have the Dell’Orto.

So why didn’t it catch on? The consensus seems to be a matter of parts availability. Dell’Orto (sometimes spelled without the apostrophe: “Dellorto”) is a small Italian outfit, and it seems they never really had the financial ambition or production acumen of the better-known Weber, and as a result, parts are more difficult (though not impossible) to come by, in contrast the Weber’s almost Holley-like myriad of configurations and applications.

That said, the Dell’Orto was spec’d for a number of factory (not just aftermarket or racing) applications, among them the twin blow-through turbocharged setup for the first-generation Lotus Esprit Turbo, shown at top. They were also used on several Alfa Romeos, and the carb was always praised for its excellent fuel atomization and efficiency, such as it was. It’s a popular aftermarket carb for applications as diverse as Mazda rotaries, Porsche flat sixes or Nissan L-series engines.

And what makes it so much better-behaved than the temperamental Weber? The main reason is a larger accelerator pump. To cover the lean condition and avoid the potential engine stumble when the throttle is quickly opened, the carb provides a quick shot of fuel via the accelerator pump. Nearly all carbs have them (SUs being a notable exception); however, the Weber’s are proportionately small for the carb, requiring bigger main jets to provide fuel to cover for the transition from coasting/idle to the main circuit. The result is lack of metering precision and efficiency for the Weber compared to the accurate, miserly Dell’Orto, although the Weber’s ultimate fuel delivery potential surpasses its rival, generally-speaking. Given the choice, for the kind of driving I do, I’ll take the Dell’Orto hands down.

Editor’s note: This post is part of an ongoing series highlighting various obsolescent methods of fuel delivery. Read the other installments here:

• Rochester Fuel Injection
• Continuous Injection (K-Jetronic)
• Single-Point Injection
• The SU carb

Inspired by the recent hullabaloo over the possible phase-out of BMW’s longstanding “no V6s” philosophy, I thought it might be interesting to ponder which marques have been most closely associated with various engine configurations throughout automotive history. Enjoy:

• Inline 6: A number of automakers have had great success with this configuration, notably Mercedes, Nissan (with their L- and RB-series) and Jaguar (XK engine), but the cylinder layout has to be most closely linked with BMW, not only for the various sizes of the engine they produced over the years, but also for their persistence with the configuration long after their competitors abandoned it in favor of V6s and V8s.
• Inline 5: Less than 6, but more than 4? Who comes to mind when a fellow car geek says “inline 5-cylinder?” Acura and Volvo have used this layout, and Mercedes has made 5-cylinder diesels, but undoubtedly the company joined at the hip with the straight 5 is Audi after their fire-breathing quattro-equipped monsters dominated Group B rally racing during the mid-’80s. After ditching the inline 5 in the mid-’90s, I’m pleased to see it’s been making a bit of a comeback Ingolstadt-way, fitted in transverse form to the ridiculously quick TT RS.
• Inline 4: Even more than the inline 6, the straight 4 has been developed to a very high level by a myriad of car companies. That said, the manufacturer that springs most quickly to mind when pondering the 4-cylinder engine is Honda. They’ve created some truly great 4-bangers over the years, including the Prelude’s H22A and the S2000’s F20C. Unfortunately, the association with Honda is further cemented by the legions of high schoolers who throw fart-can mufflers on their moms’ Accords and drone down the main drag any given Friday night. It’s sad, but noise of an uncorked Civic 4-cylinder is something any car buff can immediately conjure to mind. Sorry, Honda.
• V8: This one’s a bit tricky, as essentially the entire American automotive industry is connected to the layout. The classic small-block Chevy engine will always be the prototypical V8, though, still in production after more than 50 years. Chevrolet wins this one.
• V6: Again, another engine configuration associated with a number of automakers. Alfa Romeo pioneered the layout in the early ’70s, and Buick developed a great V6 in the latter part of that decade, but Nissan was the first manufacturer to roll out a modern version with their ’83 VG engine, a variation of which they subsequently installed in just about every vehicle they made, from pickups to family sedans to sports cars. Give the nod to the Japanese automaker.
• V12: Here’s an easy one, for a change. Which manufacturer is world-famous for their legendary and unbroken line of V12-engined sports cars? Ferrari, of course. Of all other automakers, Lamborghini comes closest to displacing its rival as the “champion of the V12,” but is still a significant ways back with respect to the association.

On a related note, allow me to plug an article which I’ve greatly enjoyed and learned a lot from: The Autozine Technical School discussion of engine layouts and the impact cylinder arrangement has on engine smoothness.

I love engine swaps. My first major car project was an engine swap between two first-generation RX-7s, and it was great fun, albeit challenging. However, even the trial of simply replacing a car’s existing engine with an identical one served a purpose: It reinforced my admiration for guys who can combine disparate engines and chassis. There aren’t many more ambitious or exiting projects for us shadetree mechanics, and guys who do it right become heroes in their respective niches of the automotive community.

One such hero is Mark Stielow, owner/builder of the above ’69 Camaro, as reported in Car and Driver. Beneath the legendary first-generation F-body skin, Stielow has crafted a thoroughly modern car. He has either upgraded or replaced every bit of ’60s engineering, bringing it completely into the modern era—except, of course, for the styling. The spec sheet reads like a car nut’s fantasy: Supercharged combination of LS7 block and LS9 heads, Tremec 6-speed, Truetrac LSD, Brembo rotors and calipers, hydroformed subframe, rack-and-pinion steering, coilovers all around, 756 hp. Yep, 756. The acceleration figures (4.1 seconds 0-60, 11.8 1/4 mile) won’t impress many muscle car buffs who hone their cars solely for performance at the drag strip, but consider that Stielow’s Camaro can hang with the best modern sports cars on the road course as well, and it’s completely civil and tractable around town. The bandwidth here is amazing. As the automotive equivalent of a 60-year-old decathlete, it’s almost without peer.

Granted, it is a “money no object” kind of endeavor. Stielow obviously had the resources to select the best parts to perform his time-warp makeover on the ’69. But pigeonholing him as some kind of “credit card racer” would be an insult to the attention to detail required by the necessary fabrication, and what’s more, Stielow’s ability to fine-tune the components to work together to extract both the savagery and docility. Make no mistake—it’s one thing to bolt-on all the most expensive geegaws you can find in the catalog; it’s quite another to have the skill to get them to “talk to each other” and make the whole more than the sum of the parts. From the looks of it, Stielow has resoundingly succeeded.

Editor’s note: This post is part of an ongoing series showcasing awesome engine swaps and builds. Read the other installments here:

• 4-rotor Mazda RX-7 FC
• Audi V8 into S3 Lotus Esprit

I had originally dismissed this one as a pretender…until I took a closer look at its mechanicals. It has something of a cult following, too, and I’d like to believe at least part of the enthusiasm is based on some degree of dynamic ability. I can’t think of another FWD car that enjoys the Saab 900’s level of devotion without a fair amount of fun-to-drive factor. A test drive would elucidate the issue, to be sure; I should track down an owner’s club in the area. Hmm.

To clarify, the car under consideration today is the ’78-’93 “true Saab” car, not the GM-ized ’94-’98 platform-sharing jellybean. The former had mechanical uniqueness to match its looks; the second-generation 900 was built on an Opel Vectra chassis and was depressingly conventional. A couple of under-the-sheetmetal features set the first-generation car apart: Double wishbone front suspension (the best configuration for handling) and a unique powertrain orientation that enabled much of the engine to sit behind the front axle line for better weight distribution. In the case of the second mechanical quirk, the engine is turned 180°, with the transaxle underneath and drawing power from the front of the engine. It doesn’t allow the powertrain to be located fully behind the front axle line, but it’s certainly superior to, say, Audi’s practice of hanging the entire engine out over the front axle. The rear suspension, for its part, is a simple beam axle of the type that has served VW’s hot hatches well over the years.

All that said, I’d never buy one for the dynamics alone. I can’t imagine that the car really offers a fundamentally different feel than a standard front-driver. However, other factors, including a very tunable turbo engine and general quirkiness and uniqueness, deepen its appeal considerably. The cockpit is businesslike and cool and the styling, while it wouldn’t win a beauty contest, is at least consistently unique. You certainly can’t examine its contours and conclude the designers chickened out anywhere—they were determined to create something that looked like nothing else on the road, and they succeeded. It’s weird, but it’s all weird, and it works—a statement that could apply equally well to its engineering, and for that, I give the whole package props.

Editor’s note: This post is part of an ongoing series highlighting FWD cars I think highly of, in spite of my overwhelming RWD bias. Read the other installments here:

• Peugeot 205 GTI
• B4 Volkswagen Passat
• Lancia Fulvia Coupe
• Acura Vigor
• Mazda Millenia
• Citroën SM
• Fiat Coupé
• ’91-’96 Infiniti G20
• ’91-’94 B13 Nissan Sentra SE-R
• ’88-’92 Mazda MX-6
• Audi Coupe GT
• Volkswagen Corrado
• Peugeot 405 Mi16
• Volvo 850 T-5R
• 5th-generation Honda Prelude
• 1st- and 2nd-generation Volkswagen Scirocco

Today we begin a new series upholding the rapidly-fading knowledge of an obsolescent technology: the carburetor. Most modern tuners would say I’m wasting my time, but I maintain there’s a certain je ne sais quoi to carburetion, a patina, a mixture of art and science, that we’ve all but lost in our transition to computerized, sterile, efficient fuel injection. The latter may be superior in every respect, but as with record turntables, Polaroid cameras or arcade games, we do lose something in the progression to new technology: the attendant experience. There’s value in that.

Engineers have devised innumerable methods of combining air and fuel via engine vacuum, the principle behind carburetion. My Datsun 240Z project car features a pair of SU carbs, so it’s obviously the particular design I’m most familiar with. I could get James May-ish and wade deeply into the technical particulars of the design, its operation and the like, but I’ll spare you and summarize up the pros and cons of the fabled Skinner’s Union carburetor, exhibited by many vintage British, Japanese and Swedish cars. The highlights:

• Simple design. In contrast to most other carb designs, with their multiple barrels, venturis, circuits and jets, the SU has exactly one barrel, one venturi, one float bowl and one jet. As an engineering solution to the problem of providing a correct volume of fuel and air throughout an engine’s rpm and load range, it’s uniquely elegant. Instead of optimizing a carb for one particular set of conditions and band-aiding the rest of the operating range, the inventors of the SU looked at the big picture of the engine’s requirements and worked from there. The result is a simple yet effective design that excites my inner engineer.
• Fuel metering precision rivaling fuel injection. Another consequence of the developers’ design approach is the incomparable precision of the fuel metering. The SU carb constantly adapts to whatever conditions the engine is experiencing seamlessly, whereas other carbs have discrete circuits for different sets of parameters, and transitioning between them can be less than smooth. So whatever demands are puts on the engine, the SU accommodates them perfectly and delivers just the right amount of fuel.
• Easy to tune. A side effect of the carb’s simplicity is its ease of tuning—if you know what you’re doing. Armed with a basic understanding of its principles of operation and the knowledge of a few of its quirks, a tune-up is a quick and easy affair, often no more complicated than a few readings with a synchrotester and a few screw turns. No swapping out jets, no delving into the carb’s innards. Simple.

And the drawbacks of the design:

• Airflow. The secret to the SU’s adaptability and precision is the variable venturi created by the moving piston housed in its signature dome. Unfortunately, a cylinder isn’t the most aerodynamic shape, so the airflow entering the SU invariably strikes a vertical wall before accomplishing anything else for the engine. The air loses energy it could otherwise use to draw fuel from the jet, and the engine expends power overcoming the drag.
• Sidedraft only. Another downside to the presence of the piston is that it limits the SU to a sidedraft orientation only. Unlike the rival Weber carb, available in sidedraft (DCOE) or downdraft (IDA) configurations, the piston of the SU requires gravity to operate, and thus airflow through the carb is limited to the horizontal. For some engines, say, a Porsche flat-6, this limitation renders the SU all but unusable.
• Limited aftermarket support. Within the corners of the automotive world where the SU was offered from the factory, there is a great deal of tuning lore, secrets, techniques and the like. But the inherent limitations of the carb (airflow, etc) for performance applications means the SU never really caught on in the wider performance scene. So tuning support lags far behind, say, Holley. It’s a shame, really; as lovely a design as the SU is, it deserves wider recognition.

Editor’s note: This post is part of an ongoing series highlighting various obsolescent methods of fuel delivery. Read the other installments here:

• Rochester Fuel Injection
• Continuous Injection (K-Jetronic)
• Single-Point Injection
• The Dell’Orto carb

The line between automatic and manual transmissions is losing definition. Whereas before a car buyer had exactly two choices—three-pedal manual or torque-converter automatic (perhaps with a manumatic shift mode, but still a slushbox)—in the past 10 years “flappy paddle gearboxes” of the single- and dual-clutch variety have arrived to complicate the issue. This raises the question: Are they manual or automatic? Yes, in most cases, their purpose is to replace a manual transmission, but set to fully automatic mode, the seamlessness of their shifts (dual-clutch especially) can rival the best slushboxes on the market. And they lack a traditional third pedal. So what are they?

In a their March issue, Car and Driver took a stand, switching from calling dual-clutch transmissions (e.g. VW/Audi’s DSG, shown above) “dual-clutch manuals” to “dual-clutch automatics.” They wrote:

Our conclusion is that we need to update our definition and classification of both types to reflect how they perform, instead of trying to distinguish them by the hardware they employ. Automatics and dual-clutch gearboxes both have the ability to send power to the wheels during upshifts, something no manual gearbox can do. For this reason, dual-clutch transmissions will now be known as dual-clutch automatics in Car and Driver.

Do you buy it? Should “how they perform” be the pivot point of the terminology in dispute? Or should we rather classify transmissions as belonging to one camp or the other based on how they’re predominantly used by the driver? In other words, for better or worse, to an enthusiast, the words “manual” or “automatic” do more than convey mechanical functionality—they communicate intent, and it just doesn’t sound right to call, for example, the fire-breathing BMW M3 GTS‘s gearbox an automatic, dual-clutch or no. What say you?

I promised myself I’d take more pictures. During a visit to my parents’ today, I did.

Behold, my project car, a 1972 Datsun 240Z. My dad bought it new in ’72, and gave me the keys as a college graduation present. As outlined in my previous post, it has issues, some significant, but notwithstanding those I’m eager to dig into the restoration.

It hasn’t moved under its own power since March 11, 2004. That was the date of the minor engine fire and subsequent operation without oil pressure for several minutes. Since then, it’s been parked in my parents’ garage, awaiting the day when I would have a garage of my own to transfer it to. That day has come, but its new home isn’t quite ready yet—some organization is still required. So it’s still gathering dust, 90 minutes away.

Here’s the major issue: Rust has completely consumed the passenger side floor pan and frame rail underneath. The driver’s side is fine, so why did its counterpart fare so poorly? Simple: The battery tray is smack up against the firewall on the passenger side of the car. Over the years, uncleaned battery acid ate a hole in the tray, the inner fender beneath, and the firewall itself. With all those panels swiss-cheesed, rainwater had a more-or-less direct path through the firewall and down into the floor pan, where it sat and oxidized the metal. It looks awful; I know, but again, my only hope is that I’ve seen Z-car floor pans and frame rails restored from even worse states of decay.

The L24, a 2.4l SOHC inline-6. Lovely engine. The orange, oval air cleaner assembly is in the trunk at the moment. You can see a few of the “modifications” I made prior to the car’s stasis: Air pump removed, air injection system capped off and other emissions garbage pulled from the balance tube, and an electric fan (stupidly) added to replace the stocker, whose fan clutch had seized. The carbs were rebuilt by ZTherapy in the late ’90s and have the ball bearing throttle shafts. Overall, the engine cleans up well. I just need to tear it down and inspect the internals as a matter of course.

All in good time.

Editor’s note: This post is Part 2 of an ongoing series chronicling my efforts toward the restoration of my 1972 Datsun 240Z, originally my father’s. Read the other installments here:

• Part 23: Gutting the Interior
• Part 22: The Teardown Begins
• Part 21: …And the Engine Comes Out
• Part 20: Treasure Hunting
• Part 19: Beginnings
• Part 18: VIN Discoveries
• Part 17: The Bad News
• Part 16: On The Road
• Part 15: Getting It Back On The Road
• Part 14: It Lives!
• Part 13: Restoring the Fuel System, Part I
• Part 12: Meat on the Wheels
• Part 11: Inspiration (Sort Of)
• Part 10: Carbs’ Return
• Part 9: First Triad Z Club Meet
• Part 8: Wheel Work
• Part 7: Tactical Changes
• Part 6: Little Things
• Part 5: Coming Home
• Part 4: The Rollout
• Part 3: Confessions of a Poor Car Enthusiast
• Part 1: Projecting Forward