By on August 1, 2012


This entry could very well have been included in the last series of articles (“Phil’s Podium of the Automotive Pure”), but for one important consideration: the technology involved is no longer being widely used in the automotive field. Otherwise, it solidly qualifies for “The Podium” in every other important aspect. The truth is, this technology is greatly significant in the history of the automobile—even surpassing many of the technologies listed.

Back in the early days of emissions control here in the U.S.A., in the wake of the first so-called “Energy Crisis”, which left motorists calling for more fuel economy in their automobiles due to the increased cost of fuel (if we only knew where all of THAT mess was headed!), I’d almost call it “amusing” witnessing all of the different ways manufacturers were addressing the issues.

The U.S. group, which seemed to be relying on input from “bean counters” and marketing strategists, was trying to make the old inefficient designs passable through use of a cheap and spindly patchwork of detuning modifications, add-on systems, and gargantuan catalytic converters.

The Europeans, who seemed to be actually raging somewhat at these governmental and motorist-driven demands, responded similarly as they did to the whole Air Conditioning issue, in earlier days. They went with the whole patch-and-add-on idea, but one-upped the Yanks by making their systems overly complicated, by comparison, as well as being a real obstruction to routine maintenance accessibility. They differed completely in their approach to catalytic converter use, opting initially to use the so-called “Thermal Reactor” exhaust manifold design, which were as unreliable as the first volley of catalyst systems the Yanks were using, not to mention a lot more expensive to replace.

The Japanese, on the other hand, were already positioned—more by developmental circumstances than actual foresight—to take advantage of the situation as far as the fuel efficiency issue.

As far as the emissions issue, they were somewhat fragmented in their approach.

As it turned out, Honda had a design they had been developing in the course of their foray into the passenger car field. It was called Compound Vortex Controlled Combustion—acronym: “CVCC”. While this design was not necessarily unheard of in automotive engineering circles, they were the only ones who wanted to actually be able to use it on mass-produced vehicles, where its full potential as a fuel economy and emissions breakthrough could be realized. And was it EVER!

It was so good, Honda was able to avoid the use of many add-on emissions control components common to the day. In fact, a catalytic converter was not required on any of their U.S. vehicles until 1980, and no engine management computer of any kind was seen until the 1984 model year (a feedback intake air-bleed system).

Fuel economy was nothing short of incredible, and has only been MATCHED by some of the modern hybrid Japanese entries (including Honda’s). Keep in mind that all of this was accomplished with a CARBURETOR and NO COMPUTER CONTROL!

We techs really appreciated these facts, as we saw only modest changes in underhood technology during the decade-long heyday of these engines. It was the best ten years of my automotive repair career, HANDS-DOWN!

It seemed that Honda was the lone problem-solving “Eagle” soaring above the rest of the grounded, whining and recalcitrant “Turkeys”; and Honda built its legendary reputation during this period. They continued to soar with the CVCC engine and the carburetor until the late ‘80’s, when EFI technology finally came of age, and has become the industry standard.

It’s ironic that what was accomplished by this upstart, one-time motorized bicycle manufacturing company more than thirty years ago—and was pushed aside and supplanted by a number of somewhat questionable automotive trends—is once again in demand.

Honda’s official history of the CVCC can be found here – Ed

Phil Coconis is the owner of a West Coast independent auto repair shop.






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32 Comments on “Memoirs Of An Independent Repair Shop Owner: How Honda’s CVCC Gave Me My 10 Best Years...”

  • avatar

    Honda only failing with sticking with carbs was a rats nest of vacuum hoses. I was lucky enough to make it 12 years on my 87 carbed Accord without any issues.

    A co-worker had a 89 that he ran until 2008 or 2009.
    That one was falling apart at the end, but one of things that made him get rid of it was vacuum leaks. He was afraid that in the process of tracking down the right hose that the others would crack.

    But, still, 19 – 20 years isn’t bad.

    • 0 avatar

      You’re giving me flashbacks of 110 degree heat, under the hood of a CVCC engined car, trying to figure out what hoses had cracked, keeping in mind that I surely would crack others trying to change the one or two that was bad. I had a 100 pack of single edge razor blades in my toolbox to slit the hoses so they could be easily removed, as they welded themselves to the little nipples and if you pulled on a plastic one, oops, if you pulled on a thin metal one, oops. In the late 70’s we went through a crapload of vacuum hose in Las Vegas. As bad as some of the Japanese cars of the time were, the worst in summer heat were the Fords with 460 engines in them. It was almost impossible to keep your eyes open under the hood, unless you let it sit a half hour, the heat was brutal. While their vacuum line arrangement wasn’t as bad as the Japanese cars, the heat under the hood made trying to diagnose a problem kind of like torture.

  • avatar

    “How Honda’s CVCC Gave Me My 10 Best Years” changing head gaskets.

  • avatar

    Sorry if I’m a bit slow but in what way was the CVCC giving you the ten best years…?

    Was it because it was so troublesome that you had plenty of business fixing the cars? Or was it because it was so reliable and/or so easy to fix and mostly unchanged in 10 years that you did not have to do much work on them while still getting full payment from customers?

    Apologies if this comes across as snarky. It’s not intended that way. I’m genuinely curious. Either way I say good for you

    • 0 avatar

      Agreed. I don’t get the relationship either.

      • 0 avatar
        Athos Nobile

        “vacuum computer” + leaks + drivability problems + mechanic = profits.

        I still have in my computer the diagram MM posted here a couple of months ago. One of my coworkers (himself a mechanic) saw it and said: Mother of God!

        Now if he supplies the 1980×1640 original, I can have a new wallpaper.

      • 0 avatar

        I’m guessing it was that they were terribly unreliable and resulted in lots of business. I was too little to understand or remember the details, but my grandfather had a lime green CVCC that was a total nightmare. He kept his cars forever, but got rid of the Honda within a year or two. Picked up a Sunbird wagon to replace it and never bought another Japanese car again.

    • 0 avatar

      I wondered the same thing, and I read the whole story expecting that answer at some point. I’d like to think I’m a pretty good reader (I am a librarian), but did I miss the answer in there somewhere?

      • 0 avatar

        I think it’s implied that for those ten years he enjoyed seeing Honda Engine Bays which were just that, a ‘Bay’ for an ‘Engine’, and not filled with weird add-ons or computers or electronics needing specialist training or proprietary tools.

        But I’m not a mechanic and I don’t know where the author’s prejudices lie. One mechanic’s ‘Engines I love to work on’ could be another’s ‘P.I.T.A.’.

  • avatar

    I remember these cars when I got my first 386 PC desktop (shutup, I know it was a long time ago) it came with a screen saver called ‘pipes’ that had insanely elaborate pipe networks that would fill the screen until the background was completely covered. I always thought of it as a Honda vacuum diagram.

    At least Honda numbered the vacuum lines right on the rubber tube, and it was ususalyl 1-42. Soomer or later, someone would get the bright idea to replace the lines with bulk hose. After that, you might as well junk the car.

    • 0 avatar

      How funny, I thought of the same correlation between “pipes” and Ford’s EEC-III system, which used vacuum lines for almost every EFI (vacuum actuated) sensor.

      Haven’t worked on CVCCs personally, but they could be more complex than EEC-III.

  • avatar

    I think the maze of vacuum hoses on the CVCC carb was one of the biggest messes known to mankind. The main reason they were so easy on fuel was because the car was smaller than many golf carts.
    As far as the engines used by the big 3 goes, they did just fine with emissions and fuel economy requirements for decades once proper fuel delivery systems were developed for them.
    During the late 70’s the aftermarket stepped in and started offering carbs and manifolds that increased both power and fuel mileage. Edelbrock had manifolds such as the SP2P, holley had the streetmaster, weiand and offenhauser had similar manifolds. There was also a plethora of cams designed to go with those manifolds.
    Once the automakers got their act together they got performance efficiency and low emissions from their classic engines and some of them stayed in production into the 21st century. By the late 80’s most of those engines got port injection, roller cams with better profiles for better cylinder filling which increased power and efficiency, better ignition systems and so on.
    The small block chevy was used at least until 98, somewhere around there, my memory is getting a bit fuzzy. The small block ford stayed in production past the 21st century, the small block chrysler was used until 2002, when the Hemi replaced it in 03. The ford 300-6 stayed with us through the end of 96, and the AMC 6 survived through the end of 04, I believe, or somewhere around there.

    • 0 avatar

      Most average drivers – such as my parents – did not want to bother with aftermarket parts to obtain an acceptable level of drivability. Fortunately, their 1976 Oldsmobile Delta 88 Royale Holiday sedan was good in that regard, but GM’s High Energy Ignitition system was one of the best systems around. The Chrysler Lean Burn system and Ford system weren’t nearly as good. Our neighbor’s 1977 Chrysler LeBaron sedan, bought brand-new, was constantly in the shop for one thing or another.

      My parents’ 1973 AMC Gremlin, however, was simply awful – a complete lemon in every way. Its drivability and fuel economy were lousy even by the dismal standards of that time.

      While Detroit did get its act together by the mid-1980s in how it met emissions standards while maintaining acceptable levels of performance, drivability and reliability, the point is that Honda beat them to it.

      I had a 1977 Civic CVCC hatchback that was bought used in 1980. In terms of drivability and reliability, it was ahead of anything Detroit built in the 1970s except for the full-size and intermediate GM cars with the High Energy Ignition system.

      • 0 avatar

        Geeber, I do realize that the majority of the car buying public in the 70’s did not consist of real car guys that were interested in aftermarket equipment. My point was that detroit’s engines were not the antiquated, inefficient designs that this guy made them out to be. The vast improvements in performance, driveability, and fuel economy while meeting emissions standards with the aftermarket carbs, manifolds, ect. were proof that the engines were just fine. But the automakers were late in getting off their behinds in developing good induction systems for them.
        As the 80’s wore on it was increasingly difficult to meet the growing emissions requirements with a carb, but the big 3 didn’t want to spend the money on fuel injection so they held onto the carb as long as they could, going as far as using electronic controls with them. We all know how that turned out. Once they finally realized that fuel injection would be the only way to meet future emission requirements they came out with some nice results.
        GM’s tuned port injection worked very well and was reliable, ford’s multi port system worked very good, especially on the 5.0 mustang, chrysler’s fuel injection system on the magnum truck engines also worked very well. All of these engines were the carryover small blocks from the 50’s & 60’s, the same engines that the writer of this article called outdated and inefficient.
        The jeep inline 6 ended up making 190 HP by the late 80’s, had good driveability and decent fuel economy for the application it was used in. My point was that the fact that these engines were successfully used as long as they were just goes to show how wrong this person was about them.

    • 0 avatar

      4 cylinder offerings from Ford and GM were dogs back in 1980 – especially when couple to an automatic transmission.

      A Big 6 or a V8 was still the way to go on an American sled. That Ford 300-6 had 7 main crankshaft bearings and was one of the better engines of its time for longevity.

    • 0 avatar

      The old AMC-6 was used up through 2006 in the Wrangler.

  • avatar

    I know a guy who has worked at the local Honda dealership since it opened in the ’70s. He said when they first got these little buckets of tin, nobody thought they would be durable enough to withstand the winters of the Midwest and the harsh conditions of the roads.

    The Honda sales rep that was there advised that these “little buckets of tin” could handle any of the roads around the Midwest with aplomb. He took one of the cars off the showroom floor and took him and another Honda salesman with him and proceeded to drive the car right onto a frozen river. Once he clawed his way out of the frozen river bank, he took the same car down some frozen gravel roads at breakneck speeds.

    After the Honda rep proved his point and left, the Honda salesman used that same sales approach with leery customers.* They sold every single Honda Civic that came in. Apparently there are still customers at the same Honda store who were taken on these test drives and still buy Honda’s because of it.

    *frozen rivers were not available in the summer. (obviously)

  • avatar

    NOx emissions killed these designs

  • avatar
    DC Bruce

    The article doesn’t mention one other benefit of the Honda CVCC engines vs. engines in competitive products at the time: driveability and easy starting. I owned a ’78 Accord, which I bought almost new in 1978 and must say that the car started and ran flawlessly. By comparison, many desmogged engines in Detroit products were hard to start (typically because of a very non-aggressive profile built into the automatic choke) and ran poorly, surging and having “flat spots” in acceleration. The CVCC engine in my Accord showed none of that behavior. It started reliably and easily in all temperature conditions and had the kind of linear throttle response that we take for granted with the current EFI engines.

    You have to remember that a carburetor depends upon manifold vacuum to suck the gasoline through the nozzles into the intake air stream. So, one of the biggest problems a carb designer has is dealing with the the abrupt drop in manifold vacuum which happens when the driver opens the throttle quickly. The volume of air increases immediately, but there is a lag in the increase in the volume of fuel. The result is an abrupt leaning out of the mixture causing, in worst case, stalling of the engine, or delayed engine response to the throttle (surging). In the pre-emission control days, the solution was (a) to run the engine rich and (b) to have an “acceleration pump” actuated by movement of the throttle linkage that squirted raw gas into the income airstream when the throttle was opened. High power engines with multi-stage carbs or multiple carbs, sequentially activated would do this in a very big way when the driver applied full throttle. As a result, you could smell the unburned gasoline vapor coming out of the exhaust.

  • avatar

    “Fuel economy was nothing short of incredible, and has only been MATCHED by some of the modern hybrid Japanese entries…”

    True, but the CVCC Civic weighed considerably less and had performance that would be considered unsafe by current standards.

    Then there’s the rusting fenders problem. To be sure, this was a remarkable car. But it had quite a few problems including very expensive brake rotors which had a poor operational life.

  • avatar

    I was truly impressed by the first CVCC I saw in 1982. The body work and interior left a little to be desired. Plus, I wasn’t and still not very fond of the Japanese styling from that era.

    Anyway, back in 1981 the CVCC engine made 4 cylinder econobox offerings from the Ford and GM seem agrarian. American offerings to include the Mark III Ford Escort were rather course with regards to NVH.

    VW was pretty much using EFI by 1981. Honda on the other hand had that 3 barrel Keihin carburetor, that seemed a bit bizarre to a Weber fan – but the company was already experimenting with more than 2 valves per cylinder in their head design – which unbeknownst to me was very futuristic for an econobox back in 1981.

    It’s a shame to see Honda resting on its past engineering laurels in recent years.

    • 0 avatar

      Yeah, shame on Honda for continuing to sell reliable, inexpensive-to-own cars when the market clearly demands hideously complex and finicky solutions.

      Where Honda goes awry, I’d argue, is when they do push the envelope (or cleave to their own path, counter to consumer preferences, the market and/or sanity) in terms of engineering and marketing. When they just bang off another Civic, Accord or CR-V, they do quite well.

      I like Honda, heck, I own one, but when they try to push it (the IMA hybrid system, Acuras that no one wants, refusing the acknowledge that luxury cars need unobtanium trim levels, insisting on their own transmissions) they tend not to do well.

  • avatar

    VW and Bosch solved early emissions by perfecting mass produced EFI (1968 VW Type 3). That was the long-range solution that is now universal. Honda’s 3-bbl carb, maze of vacuum hoses and manual choke was a dead end. Even without CVCC, my ’74 Ford was vacuum hose hell.

    Ford, with Texaco, worked on a stratified charge engine, but I think the Ford bean counters killed it.

    • 0 avatar

      The Stratified charge engine that Ford worked on is one and the same with the CVCC. Ford had started work on what they called ProCo, short for Programed Combustion. They got word of this motorcycle company that was looking to expand their automotive offerings and teamed up with them. They provided their data and patents on the ProCo engine as well as engineers and funding to complete the CVCC project. It was to power the 1981 Escort in the US. However Hank the Deuce said “no way in )&(*&^#$% is there going to be a Japanese engine under the hood of a car with my name on it”. Never mind the fact they had been selling the Courier. Ford walked away from the program and hurriedly designed and rushed the 1.6 for the Escort into production. The contract called for Honda to provide a ready to drop in engine and transmission for $500.

      • 0 avatar
        bumpy ii

        The whole “stratified charge” thing is a bit of a red herring. Honda was working on that in the early ’70s, and they never were able to gain suitable control over the combustion events to make it work. However, the work on improving the combustion chamber design did have the side benefit of reducing emissions by a healthy amount. This was a much simpler and more elegant approach than the kludgey after-treatments that other automakers were using.

      • 0 avatar

        The CVCC engine is a version of a stratified charge engine. They just moved the rich enough to light mixture and the spark plug to the pre-combustion chamber. That is why they needed the 3bbl carb. The small barrel that provided the “rich” mixture feeds the valve that feeds the precombustion chamber where the spark plug was located.

        Modern DI engines also are also basically a stratified charge engine.

  • avatar

    These cars were great for mechanics. Head gasket replacement was quite frequent and the book time was high since you were supposed to remove the intake and exhaust manifolds before the head. That was darn near impossible so once you figured that out and pulled the manifolds and head as an assembly you could beat the time by a mile assuming all the vacuum lines were stock with their circuit numbers and the hood hadn’t been replaced taking away the map of where all those hoses went.

    Speaking of hoses no they didn’t have an electronic computer but they had the “vacuum computer” which there was no way to test, at least available to the independent mechanic. The 3bbl carburetor needed to make the stratified charge engine work was not cheap and had some issues too. At the shop I worked at when the CVCCs were still on the road we had 2 special, made in the shop, wrenches specifically for the CVCC. A 10 MM with a ~90 bend in it for removing some of the carb bolts and a 12mm with a ~30 degree bend to get the lower manifold bolts should one attempt to remove the manifolds w/o removing the head first.

  • avatar

    As the former owner of a new ’76 Civic, and a near new ’79 Accord, I found the CVCC design to be of questionable superiority over other more pedestrian designs of the day. It was definitely not ready for prime time. I believe the real benefit was marketing a car that didn’t require unleaded fuel.

    There were the typical head gasket failures, the labyrinth of vacuum hoses, the failed auxiliary valve guide seals, and driveability issues. I also fail to see where these offered superior fuel economy. To what, a ’74 Buick, a ’72 Vega? My ’79 Accord gave me only 23-24 miles to gallon in mixed use, where my ’71 VW Super Beetle was giving me 26 mpg. The Accord was only 150lbs heavier, although it did have to meet stricter emission standards. My ’84 Nissan Sentra with a feedback carburetor gave me 36-39 mpg.

    I think Honda should have done a far better job of developing the CVCC for durability, and gone to a catalytic converter in ’75. These were the worst cars I’ve owned, although I’d consider a Honda today. The CVCC had intellectual and marketing appeal, but in reality was a gross disappointment.

  • avatar

    Head gasket problems have been mentioned a couple of times. From my own experience, the head gasket failing was an effect, not a root-cause issue.

    American iron block/iron head engines were (in general) fairly tolerant of overheating, while iron block/aluminum head (and all-aluminum) engines were not. American drivers were not used to this, much as they were not used to having to change a timing belt every 60K miles.

    Overheating one of these engines typically led to blown head gaskets, either immediately or shortly thereafter. In my experience, the flow rate of the original radiator with over 100K miles was often severely limited due to internal crud buildup (due to lack of proper coolant changes and the use of mineral-laden tap water), and this often led to an overheating situation.

    The CVCC engines were also incredibly sensitive to the type of spark plug used – the stock NGK was the only way to go.

    • 0 avatar

      I should have mentioned in my above post that the head gasket failures I experienced had nothing to do with overheating. Admittedly, what typically happened on the CVCC cars was that the fan switch would fail, then the engine would overheat, causing the head gasket to fail. I knew about this from other hapless victims. Plus, I was even more fanatical about keeping fresh coolant in the engine than I am now. No, my cars head gaskets failed because the design wasn’t developed enough. True, Honda was far from the only manufacturer having these head gasket failures due to the different head and block material.

      If there wasn’t a problem with the Honda design, there wouldn’t have been a head gasket recall in 1978.

  • avatar

    VW got smart in that era also. The Bosch CIS (K-Jetronic) fuel injection system introduce in 1977 was delightfully simple and kept the vacuum line plumbing to a minimum as well as allowing pre 1980 cars to run without a cat. This shows up clearly if you contrast a 1984 Jetta with a 1984 Accord, since my family had both.

  • avatar
    Phil Coconis

    To all commenters:

    It seems that I’ve struck a nerve with many on this topic.
    Stay tuned for the next “Memoirs” entry, where I’ll provide rebuttal.


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