I have owned a great number of automobiles over the years and recently was sold a 1994 Pontiac Grandam for $350 with efi and automatic transmission. I was so impressed by the raw brute power coming out of this little 3.1 liter v6 engine that I was sure it had overhead cams and a timing belt etc. The last time I drove something with this same getup'n go was a couple of years ago, which was a 1990 Plymouth Acclaim with a 3 liter engine with overhead cams and timing belt. I have found both cars to be near identical in power and performance and this left me wondering if there isn't a whole lot more to this debate, than just this difference between the 2 types of engines. For instance my Ford minivan has a 3 liter engine as well but yet this van's acceleration can at best be described as gaining momentum. From a reliability point of view in reading different forums debating the issue of which is better between the two, it has usually came down to the timing belt which provides limited reliability and requires more maintenance. Some auto manufacturers have kept the overhead cams or even dual overhead cams but have provided a very long timing chain in lieu of the timing belt previously used. With dual overhead cams the number of parts required and the subsequent weakening of the heads to accommodate the extra holes is not a plus. The very long chain has not came without it's limitations as well, as it's much more difficult to maintain the right tension on such a long chain. It is also not uncommon to have the entire spark-plugs pop out of the aluminum engines with aluminum threads because of the obvious reason coupled with the higher resulting compression found in these engines, resulting in lower reliability. ex.(Ford Triton engine). The cost of using such a long timing chain has required that manufacturers use chains made in places with cheap labor and standards resulting in defective chains that have come apart thus damaging major engine components, which luckily for the consumer were often repaired while still under warranty. ex: A co-worker of mine bought a new (Intrepid, made by Dodge), just a few months later was left walking as his timing chain had came apart. Luckily for him it was still under warranty. For myself I like reliable first before performance and fuel economy, I really like to be able to complete my drives to and from work without breakdowns. I prefer quiet performance so I can listen to a great sounding car stereo, not the annoying rumble and rasping irritating noises of what some refer to as performance. I prefer great fuel economy without having to suffer lack of performance, it's nice to have a choice all under the same hood, matched with superior reliability. The conventional engine from what I have seen lately still offers all of that. For instance my gas mileage on my 94 Pontiac Grandam is 36mpg hw and 28 city, all from a v6 engine. The 4 cylinder model I had previous was an 86 model, also efi was gutless and only got 28 mpg hw which was insufferable. This gas mileage was naturally calculated in imperial gallons converted over from liters at 4.5 liters to the imperial gallon. The U.S gallon is much smaller at only 3.89 liters to the gallon, their road tests performed at only 42 mph in order to calculate hw fuel economy and city is performed at a continuous speed of 30 mph, with neither reflecting what the actual fuel consumption would reflect in reality. When buying jugs of motor oil in Canada it is common to see different sizes of oil jugs. there are 3.89 liter oil jugs, 4 liter and 5 liter, depending on the manufacturer and location of refinery. To summarize this topic, The British Quad-4 and the 1911 Stutz racing cars, both remain a testament to the fact that for performance and racing purposes the overhead cam engine delivers nearly equivalent power with far greater fuel economy to that of much larger conventional engines. Yet these 4 cylinder engines have lost their edge in the field of racing, due to the same designs now having been incorporated on the larger engines, thus creating super-cars. Racing car engines require more maintenance anyways, so frequent replacement of timing belts on these remains a non-issue. Also if these break down, the driver doesn't usually have far to walk. For the rest of us whose purpose is going from A to B, the choice remains with reliability. You can't get the same performance out of a timing belt, which will never last the lifetime of an automobile, unlike a nice short timing chain mounted on a conventional engine. Instead of moving towards less maintenance and greater reliability manufacturers have cheaped out in so many areas just in engines alone that one must wonder why the move away from the flat head engine in the first place. For viewing of the flat head engine google, flat head engine images. These were still the best engines ever made, especially for the proper balance between all of these following, performance, reliability, durability with less parts, way less parts than today's engines. Today computers for engines double the cost of an engine and yet in 1957 GM had fuel injection without a computer mounted on some of their engines, proving computers aren't necessary on vehicles, they are just used to justify the need for computer technicians and the need for more parts for manufacturers to sell to their customers. All of these combines has nearly tripled the new selling price of today's automobiles beyond what they should be selling for.
