[120ihatch]

Garage Queens

Why are there low mileage sports cars that have ruined engines? Why do they have electrical problems?

Ferrari automobiles are perhaps the most problematic. But Why? It seems that most of those who purchase a Ferrari do not often drive them, and when they do they abuse them. Let me explain.

Each morning the lawn is wet with dew. This is because as the temperature drops the dew point is reached and the moisture in the air condenses. This happens in your engine as well. There is air and moisture in the engine. As it sits over night the moisture condenses. It is a repeating cycle. It is actually worse than the outside air. After driving the engine is very hot so as it cools it sucks in a lot of moist outside air.

Remember the products of combustion are water and CO2. The water condenses in the engine during start up and even steam blows by the piston rings for another source of water.

There are additives that help the oil absorb water but if the engine is not started then the water that condensed in all parts of the motor keep it wet. If the car lives near water or worse, salty water, then the situation is compounded. Another thing that makes things worse is mildew and fungal growth, yes it can even grow in oil!

Water is bad but there is another source of corrosion, acids. These result from byproducts of combustion that slip past the piston rings and from fuel dilution of the oil. Again, the oil has additives to neutralize these acids but work only when the oil is splashed around the inside of the engine.

Corrosive products and water in the atmosphere also take their toll on electrical components. Electrical switches are problematic. These are helped by using the switches. When you get in the car and role down the windows and click all the switches they scrape some of the thin corrosion off the contacts. Again, use of the car helps whereas sitting around is detrimental.

Fan and timing belts age at accelerated rates when static and in cold climates. Cold is also bad for plastic, leather and all rubber like parts. Winters are tough on cars. Up north it is cold and the cars get little use. And down south it is moist all the time. Moisture is an independent factor increasing engine wear. Engine tests are usually performed in controlled humidity environments.

People think that taking the car out for a 10 or 15 minute spin will keep it in good shape. Well that is better than nothing because at least everything is splashed down with oil in the engine and some switches are activated that helps remove corrosion. But to burn off excess fuel and water from the oil it must be brought up to full operating temperature. This takes 20 or 30 minutes. Your coolant heats up in as little as 2 – 3 minutes but oil takes up to half an hour to get up to full operating temperature. You should drive the car for another half hour or more after the oil is up to temperature.

People do not realize that “severe” driving conditions that require more frequent oil changes include stop and go city driving of only 20 minute drives or less. This is a severe condition because the oil never gets hot and never burns off the extra fuel or water. For this reason the oil must be changed more often.

Now for my favorite topic, cavitation. This is what accounts for the greatest wear in minimally used engines (in my thinking). Cavitation occurs in fluids when they cannot be moved fast enough. In the bearing the oil is thick at start up (75 F) and yet the parts are moving fast. Vacuum bubbles result. When they collapse there is a huge force that pulls chunks of bearing material from the lining. The chunks may include the full thickness of the bearing. Sometimes pits are seen on bearings and blamed on corrosion or improper lubrication but the culprit is more likely to be cavitation.

People start up their cars and rev up the engines. They impress their friends with the Vroom, Vroom, Vroom over and over again. Then they take the car out for a spin and rev up the RPM. They do this immediately, while the oil is well below operating temperature and relatively thick. I know of engines ruined in this very manor.

The moral of the story is drive your cars often and do not rev them up until the OIL is fully warmed up. Using an oil that is not as thick during the start up period should minimize the effects of cavitaion. This is why I advocate the 0W-XX oils, they are less thick at start up.

aehaas