| |
Timing Belt Replacement
Sooner or Later, a Timing Belt Will Get Your Attention!
Whenever people discuss cars, it usually doesn't take long before the subject of Preventive Maintenance pops up. These days, most people
are very familiar with the typical areas that need maintenance on their cars. Some of these include: oil changes, transmission servicing,
cooling system flushing, and the list goes on. However,
there is one item that is easily overlooked, the timing belt. I'm not sure if it's because not all cars have them, or because it needs
attention so rarely, but timing belts, many times, will go completely unnoticed - at least until an unexpected breakdown occurs!
Considering the amount of damage and expense a broken timing belt can cause, it's surprising that this is such a common problem.
With some cars today, a broken timing belt can cause enough damage that a new engine is the only hope. In this article, we would like to
help you get a better understanding about timing belts.
Illustration Key -
1. Camshaft(s) - Camshafts must be timed to the crankshaft. For engines with more than one camshaft, each camshaft must be timed with each other, as well as with the crankshaft.
2. Crankshaft - The crankshaft drives the timing belt, which in turn drives the camshaft(s); and, as seen hear, sometimes other components such as the water pump.
3, 9. There are various marks that are used to insure the camshafts are aligned properly.
4, 5. Multiple covers are used to cover and protect the timing belt and related components from water and dirt contamination.
6. Also attached to the crankshaft is the crank pulley, which drives the accessory belts (alternator belt, power steering belt, etc.)
7. The Timing Belt Tensioner has roller bearings which over time and mileage can fail. This is inspected for smoothness of operation during timing belt replacement.
8. The crankshaft bolt attaches the crank pulley(s) to the crankshaft.
10. Sometimes spacers are used to keep timing belts from trying to 'walk off' the pulleys.
WP. Water Pump
What's a Timing Belt Anyway????
 A timing belt, like many other parts on a car, can be difficult to explain, especially if you happen to be a person not familiar with some of the inner workings of an automobile engine. For this reason we will try to give the simplest explanation we can of what a timing belt does, and why it is so critical to the operation of your engine.
A timing belt is a strong, toothed belt, usually located on the front side of the engine. You don't normally see the timing belt because a plastic or metal cover protects it from dirt and water contamination. The timing belts job is to keep two different vital parts of the engine "timed" and rotating together without interference. When both the camshaft and the crankshaft are 'in time', the valves in the engine's cylinder head will open and close at their proper sequence.
Okay, enough technical jargon, how about a less technical example? Almost everyone, at one point or another, has used an electric or hand operated beater (yes, I am talking about a cake mixer/beater). Specifically, the kind that have 2 spinning mixing beaters. Have you ever noticed that the 2 beaters never hit one another while they spin? No matter how fast you go the 2 beaters stay perfectly meshed together. Looking at the way the tool is "geared", the two beaters are "timed" in such a manner that under normal use, the beaters will never touch each other. Now, let's stray from the normal for a minuteWhat if, while using your electric beater, at full speed, suddenly the gearing slipped and the beaters hit? More than likely, you will very quickly have a mess of twisted, broken and bent metal. Now, relate this to your car's engine. In the top of your engine there is a spinning camshaft controlling valve opening and closing. In the bottom of your engine is the crankshaft, which as it turns, is pushing the engine's pistons up and down at a feverish speed. The timing belt keeps both of the camshaft and crankshaft spinning together, yet timed so that the pistons and valves don't hit each other. As you can imagine, if that that belt were to slip or break, and the engine's pistons come up while some of those valves are open when they are supposed to be closed, damage to the valves, possibly even the cylinder head can occur. Engines that are susceptible to this kind of damage are referred to as 'interference engines'. Most cars fortunately will not experience any major damage, just an unexpected breakdown, tow and repair bill. But, in some cases, you may be looking at hundreds, if not thousands of dollars to repair the damage done. When this happens, it sad to think that a simple preventive maintenance repair could have prevented all of it.
When Should I Replace the Timing Belt in My Car???
In almost every case, it is best to follow your manufacture's guidelines for replacement of timing belts. Should a service schedule is not be available for your car, we would suggest replacement at 60,000 miles. This mileage seems to be the minimum that any carmaker has ever recommended.
Why is Other Work Sometimes Recommended at the Time of Timing Belt Replacement???
There are some other maintenance type items that should be considered when having the timing belt replacement. These are items that you typically not see in your maintenance schedule, but typically have a life expectancy of between 80,000 to 100,000 miles on most cars. The items I am referring to are: the water pump, certain oil seals, the timing belt tensioner, and the accessory drive belts.
Some Engine Oil Seals are more accessible during timing belt replacement. They are located in the front of the engine and keep engine oil from leaking out around the camshafts and crankshaft. The rubber part of oil seals get brittle over time and they lose their sealing ability. For this reason, it only makes sense to spend a minimal amount of money to replace the seals while you are already so deep into the engine. After all, if these seals were to leak 1,000 miles after the new timing belt is on, all the work and expense of the timing belt would need to be done again to access the engine oil seals!
The water pump is usually the same situation. These pumps are generally located at or near the timing belt. Some water pumps are even driven by the timing belt. Doing the pump while it's accessible is again, much less expensive than a few thousand miles after the timing belt replacement.
The Timing Belt Tensioner has a roller bearing that, over time, will begin to fail due to dirt and contamination and it's lubrication drying out. We inspect each timing belt tensioner for roughness in the bearings and recommend replacement if there is any roughness. You want to make sure that the tensioner is going to last the life of the timing belt or premature failure will happen.
Accessory Drive Belts have to come off the engine to get to the timing belt, so it makes sense to replace those at the time of that procedure (unless those accessory belts have been replaced and are fairly new).
The Sum of the Matter
There are three important things to take away from all of this. First, find out if you do have a timing belt type engine. Second, what, if any, damage will occur if your timing belt breaks, or slips. Third, and most important, don't shop for the cheapest guy in town to do your timing belt! Often times, low prices means you are not getting the full job. Remember about engine oil seal and water pump replacement, short cuts here will cost you double later! At LDG Automotive Specialists, our goal is to insure that you have years and thousands of miles of trouble-free, tow-free service from your car.
|
|
|
|
