by Douglas Samuelson

Created on: June 03, 2008

I have been involved in the automobile repair business for fifty years. If I was to attempt to elaborate on my opinion of the design and manufacture of automobiles during this time, I would have to write a book, so I will limit this article to the question: Are cars these days built to break?

I do not think that cars are built to break, but I sincerely believe that they could be built to last longer and cost less to repair when they do break.

Automobile manufacturers are in business to build lots of cars and make lots of money. It is obvious that they are not in business to make cars that will last forever. The technology is in place for a manufacturer to make a car that would outlast any car that has been manufactured since the very first car was produced, but it's not going to happen.

Prior to the over-head camshaft engines used in most cars today, most conventional push-rod engines utilized a timing chain and gears to drive he camshaft. Early on, most manufacturers used metal timing gears, but somewhere along the line someone got the brilliant idea to use an aluminum camshaft gear with plastic teeth. It was said that this was done to eliminate noise. In most cases the aluminum/plastic gear would last for 60000 to 70000 miles at which time the plastic teeth would break off of the aluminum hub necessitating replacement of the timing components. Some high performance engines experienced failure within less than 10000 miles. The replacement gears were usually metal and I cannot recall that I ever experienced a noise from the replacement gears, and they would usually last for the lifetime of the engine.

Most overhead camshaft engines utilize a timing belt to drive the camshafts. Most manufacturers recommend replacing the timing belt at 60000 mile intervals. I do not disagree with the replacement interval but I have two issues regarding timing belt replacement. Number one is the complexity/cost of replacing the timing belt or belts. It is possible to design an engine so that this operation is relatively simple and inexpensive. There are a few engines that require less than two hours to replace the belt but there are many that require five hours or more. At $80.00 per hour plus the cost of the parts the cost can easily exceed $1000.00. Number two is the "interference engine". An interference engine is one that does not have provisions for piston to valve clearance in the event of timing belt failure. On these engines the pistons will contact the valves if the timing

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