May 4th, 2010 admin
Introduction To Camshafts
If you’re unfamiliar with camshafts, you’re in for a treat. Maybe you’ve overheard mechanics talking about them, and you know they have something to do with car engines, but that’s about it. Well fear not, because you’re about to get a crash course in what exactly this part is and what it does.
Back To Basics
The engine in your vehicle contains two rotating shafts. At the bottom, you’ll find the crankshaft. When your pistons fire (as a result of pressing down on the gas pedal) it causes the crankshaft to turn. That keeps the pistons in a fixed position relative to one another. Because of the way the engine works, only one piston can be at the very top center position at a time. The crankshaft ensures that the pistons will come to that center spot in a specific order at the right time.
Now, when the spark plug fires, it causes the air and gas mixture to burn, and subsequently forces the piston down. When the piston descends, it turns the crankshaft at the bottom. The turning of the crankshaft is what causes the flywheel and drivetrain to turn.
At the top of the engine is the camshaft. It regulates the timing of the opening and closing of the valves. That ensures that when the spark plug fires, there will be gas present. The exhaust is properly emptied so that the air and gas mixture can be reloaded and the entire sequence can occur again (over and over).
The most critical parts are the lobes. While the camshaft is spinning, the lobes are the parts that actually open and close the intake and exhaust valves. They do so in perfect synchronization with the pistons. Interestingly, engine performance at various speeds is directly affected by the shape of the lobes. Therefore, engineers place great emphasis on their production, depending on what type of performance capabilities the vehicle needs to have.
The most common types of camshafts are as follows:
- Single Overhead (SOHC)
- Double Overhead (DOHC)
- Pushrod
Without going into too much detail, here’s a brief overview of the main types:
Single Overhead
This type of camshaft has one cam per head on the engine. In other words, a straight 6 (inline 6 cylinder) engine would have one cam, while a V-6 would have two (one for each of the heads).
Double Overhead
You guessed it; double overhead cam engines have two for each head. So, using the same scenario as above, an inline-6 engine would have two cams, while a V-6 would have four.
Pushrod
The main difference between pushrod cam engines and singe/double cam engines is that pushrod engines have the camshaft actually located inside the engine block, rather than on the head.
If you believe you may be experiencing engine problems due to a malfunctioning camshaft, you should see a mechanic as soon as possible. Even though I describe a lot of these systems in these columns, repairing the components involved requires a trained hand. Unless you’re experienced, check with your mechanic. Most of the problems that involve this part are best left to a technician.
Muscle Cars
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October 21st, 2009 admin
3 Strategies To Boost Your Vehicle’s Horsepower
The muscle car is a part of America’s heritage. It is steeped in the nation’s lore and has become a symbol of the individualist’s spirit. That said, over the past 30 years, there has been less attention devoted to boosting a vehicle’s horsepower. While fuel efficiency and design have taken center stage, muscle has taken a backseat.
Fortunately, drivers who want to add power to their engines have a number of options available to them. Whether their goal is to win weekend drag races (not recommended) or gain a valuable jump on steep hills, the following three strategies can boost your car’s horsepower.
#1 – Supercharge Your Vehicle
A supercharger increases the power of your engine’s output by condensing the oxygen in the air-fuel mixture used during combustion. Because there is more oxygen present, the engine can add more fuel. The result? A significant boost in output. This same “air compression” strategy is also used by turbochargers. Together, they’re referred to as forced induction systems. The downside is the cost. These systems can cost between $1,000 and $10,000 – or more.
#2 – Install A New Chip
All modern vehicles have computer chips (called engine controller units, or ECUs) that manage certain features of the engine. When a car, truck, or SUV rolls off the factory floor, the ECU is programmed by the automaker. The settings are usually geared toward delivering higher fuel efficiency. As you might expect, that limits your horsepower.
You can purchase aftermarket ECUs that are specifically programmed to deliver more power. The increase in output normally comes at the cost of lower fuel efficiency, but automakers have yet to design an affordable engine that can deliver both simultaneously. A high-quality aftermarket ECU will typically cost under $600.
#3 – Integrate A Cold Air Intake System
This is one of the least expensive methods for boosting your vehicle’s output. Normally, air is taken into the engine and added to its combustion process. The amount of fuel added to the mixture is dependent on the amount of oxygen. A cold air intake system delivers cooler air to the combustion process. It is denser in oxygen. As a result, more fuel is added, which makes the combustion output more potent. These systems can cost between $100 and $500, depending on the quality and the manufacturer.
A couple of quick notes: First, if you modify the air compression level, you may need to switch to high-octane gasoline. Otherwise, your pistons can misfire. Second, adding more horsepower usually translates into more heat and higher temperatures. Consider using a synthetic oil that can keep the individual components well-lubricated while managing the extra heat.
There is a viable strategy for boosting your vehicle’s horsepower regardless of your budget. If you’re looking for a little extra power, consider installing a supercharger, performance ECU, or a cold air intake system.
Muscle Cars
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August 21st, 2009 admin
When To Finally Retire Your Vehicle
Your car has a certain number of years during which it will perform flawlessly. Its fuel efficiency and engine performance will remain high and the need for repairs will be all but nonexistent. Eventually, small problems with various parts and systems will emerge. For example, your alternator may fail, your fuel injectors might become clogged, and your spark plugs may go bad. They’re easy enough to fix and relatively inexpensive, even if inconvenient. However, these are signs that your vehicle may have begun its long downward spiral toward retirement.
There’s plenty you can do to keep your car in great working order for many years. Routine maintenance goes a long way toward extending its life. That said, the following factors may signal that the time has finally come to retire it.
The Onset Of Rust
Rust is the equivalent of a terminal disease for automobiles. Once it sets in, it spreads. Before long, it has crept throughout your vehicle, weakening its structural integrity. At that point, rust becomes a safety issue. Getting rid of your rust-ridden car can help prevent injury to you, your passengers, and other motorists.
Repairs Become More Costly
Replacing an OEM alternator may cost a few hundred dollars (including labor). The same is true for catalytic converters. Replacement hoses will cost under $20 while a new battery may cost $60. These are minor repairs. However, vehicles with a large number of miles eventually need major work. The engine may need to be replaced; the transmission might need a complete overhaul; the frame may need adjustments. These repairs may cost over $1,000; in succession, they can quickly empty your bank account.
While it’s possible to keep an automobile in working order for decades, major repairs often signal the beginning of the end. Compare the cost of the work to the value of your car. It may be time to upgrade to a later model.
A Stream Of Failing Parts
As costly as an engine rebuild and transmission overhaul are, a perpetual string of failing components can be just as expensive. One day, your car is in the shop to have the catalytic converter replaced. Two weeks later, you’re back for a new water pump. Next month, your EGR begins failing. Before long, your muffler, ignition switch, timing belt, and master cylinder start to develop problems. These “small” repairs can become extremely costly. If there’s no end in sight, your vehicle may be preparing for retirement.
For most people on a limited budget, keeping an older car is usually preferable to upgrading to a new model. Occasionally replacing parts is less expensive over the long run. Plus, new vehicles lose a significant portion of their value during their first four years of life due to depreciation.
Having said that, your car won’t last forever. Use the above criteria as a barometer of when it’s finally time to retire it.
Muscle Cars
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