Niagara Gazette — So as of lately, a couple of questions seem to be repeating themselves in my reader’s inquiries. The first one is breaking in a new car, a popular topic among those of us that remember when this was a topic that was actually covered in the new car owner’s manual. This second topic is also popular these days given the heightened price of a gallon of gasoline. Octane ratings, and what they mean to us as motorists.
Breaking in a new car
DARREN FROM PHILADELPHIA: Do you still have to “break in” a new car and, if so, for how many miles and at what speed? I just bought a new Cadillac and want to break it in right.
TOM: Drive the vehicle as you normally would, change the oil and filter at 1,500 miles, then get on a regular maintenance schedule as per the manufacturer (read you owner’s manual). Enjoy the ride!
Darren brings up a popular question. A lot of people think there are some special things they have to do to “break in” their cars.
What does it mean to “break in” a new car? — Years ago carmakers gave each new vehicle owner a set of parameters to follow in order to break in their new car’s engine. These guidelines included such things as driving at 50 mph for a designated amount of time, followed by varying speeds on back roads, and sitting and idling for a time. After going through this process, the driver was instructed to shut off the engine and let it cool down before driving the car again. Why go through this process? To establish new mating surfaces, seat new piston rings, establish new seal surfaces, condition new mechanical parts, and so on. After the “break in” period the car could be driven without concern.
Do you still have to “break in” a vehicle today? — In a word, no. Lubricants and engine oil have come a long way compared to the products of old; they protect metal parts much better than their predecessors. In addition, the steel and aluminum used for engine parts come from the factory already conditioned and treated and ready to run. The only caveat is: Change the oil and filter for the first time at 1500 miles because some metal has worn off when mating surfaces were establish during the first 1500 miles. The oil filter should be changed as well, because it will contain more wear material at this time than at any other time in the life of the engine (assuming you don’t go for the world record between oil changes down the road).
How often should I change my oil? — Another excellent question. Your carmaker publishes a maintenance schedule in your owner’s manual. The outline for recommended oil and filter change mileage intervals are in that manual. Please read it! You will note that there are two service schedules for your car: Normal and severe. These terms (normal and severe) are defined and described by the carmaker. Determine what service description fits your driving habits and the environment in which you drive your car, and follow the appropriate maintenance schedule. Consider changing over to synthetic oil at the time of the first oil and filter change to maximize engine life and decrease internal wear (check your owner’s manual first before changing over just to make sure there are no caveats from the carmaker). I recommend AMSOIL or Mobil One because they are the best synthetic motor oils on the market.
Gasoline, octane ratings, and your car’s performance ...
IRENE FROM BROOKLYN: My car calls for regular gasoline, but I want to use premium grade. Will this harm the engine? I’ve heard you can’t do it the other way around. However, I always thought using premium gasoline would help my car run better, even though the manual says to use regular. Is this true?
TOM: Fuel octane has nothing to do with the quality of gasoline or how the car will perform. It has everything to do with how the gas acts in the combustion chamber environment. If your carmaker suggests you use regular octane fuel (87) then use it. Using a higher octane will not make your car run better.
Irene brings up a subject that a lot of people ask me about, and one that is commonly misunderstood. Let’s take a closer look at why Irene should use regular gasoline.
What is octane? Fuel octane is a measurement of a fuel’s volatility factor in the combustion chamber. In simpler terms, octane is a measurement of how the fuel combusts in the hot combustion chamber environment.
Can I use regular gas (low octane) in my high performance car? Different octane gas was developed to accommodate different grades of performance engines. The higher the performance engine, the hotter the combustion chamber environment, and the higher the octane used. If low octane (regular) gas is introduced into a hot, high compression combustion chamber found in high performance vehicles, it pre-ignites, creating a condition called “engine knock.” Why? When the low octane fuel enters the combustion chamber, it ignites prematurely. The result is the ping or engine knock you hear. Over time, continued engine knock results in damage to the tops of pistons, cylinder head faces, and valves. I have seen literally hundreds of high performance engines where the cylinder heads, piston faces, and valves were melted due to the constant use of low octane (regular) gas.
Can I use regular gas in my high performance car in a pinch? Sometimes you go to fuel up and the gas station is simply out of high-octane fuel. So what do you do? Go ahead and use regular to get to where you’re going, but don’t make a practice of it. Remember, “continued use” of low octane fuel in a high performance engine will damage it over time. Built into the performance system of today’s engine is a device called a “Knock Sensor.” The sensor constantly measures combustion chamber pressure. When it senses excessive pressure from pre-ignition, it sends a signal to the ECM (Engine Control Module) to back off on ignition timing. This feedback system minimizes the effects of using low octane fuel. Note I said minimizes, not eliminates. Continued use of low octane fuel in a high performance engine will damage it over time.
Will using high-octane fuel in my car that calls for regular gas make it run better? NO. High-octane gas was developed for high performance engines that run higher compression ratios and thus hotter combustion chamber temps. It makes no difference whatsoever in an engine that runs on regular gas. Premium gasoline will not enhance performance or increase fuel mileage if your car’s engine does not require it. Use the grade of gasoline recommended by the manufacturer.
‘Til next time ... Keep Rollin’"America's Car Show" with Tom Torbjornsen airs 7:30 p.m. Wednesday, 9 a.m. Thursday and 11 a.m. Saturday on WBBZ-TV.