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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July 7th, 2009 admin
Common Automotive Questions Asked By Owners
Even though cars have been around for over a century, most drivers are still mystified by what happens under the hood. In their defense, keeping up with the latest technologies is difficult. Automakers are in a perpetual race to design better parts and systems to improve comfort, safety, and reliability. Still, motorists have questions that deserve answers. Below, I’ll address three of the most common automotive questions drivers continue to ask.
#1 – “Do I Need To Let The Engine Warm Up?”
Unless you’re driving an older vehicle that uses a carburetor instead of a fuel injection system, no. It was common long ago to allow your engine to warm up for five to ten minutes before driving. A large part of the reason was due to the choke, which allowed fuel to feed into the carburetor. Today’s vehicles use fuel injectors to balance the air-fuel mixture used by your engine. No warm-up required.
#2 – “Why Are My Brakes Squealing?”
There are a couple of factors that can cause your brakes to squeal. First, the noise might be caused by a vibration occurring between the pads, which normally squeeze against the rotor. This type of vibration is usually due to a poor fit on the calipers. The squealing might also be caused by the surface of the brake pads rubbing against the metal of the rotor. This happens when the surface of the pads harden due to the heat created by friction.
Unless your car is equipped with high-performance brakes (which squeal naturally), have the pads replaced if you hear persistent squealing. If you wait too long, the rotor might become damaged, which is more expensive to service.
#3 – “Will My Battery Lose Its Charge?”
Over time, yes. However, a healthy car battery should last for years. Your vehicle has a charging system that allows the battery to keep its charge while providing the current needed to power the engine. When you turn your key in the ignition, your battery discharges a large current in order to power the starter motor. After it does so, its job is effectively finished. The alternator makes sure that your battery has enough “juice” or amperage for the next time you turn the key.
Having said that, it is possible for your battery to lose its charge. For example, leaving a door ajar overnight will cause a drain.
One of the reasons we take our cars to a mechanic is because they have grown in complexity over the years. Not only are problems more difficult to identify, but fixing them can be labor intensive without the proper tools. However, many of the smaller maintenance and repair items that mechanics handle (for example, replacing a battery or a set of brake pads) can be performed at home. While your vehicle may be a complex piece of machinery, it is only as mysterious as you allow it to be.
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April 30th, 2009 admin
Common Mistakes Car Buyers Make
Automakers, desperate to sell their inventories, have begun offering attractive incentives to lure prospective buyers. But, finding an automotive bargain can still prove elusive. Car dealerships can easily confound buyers and secretly hide pockets of profit. For the unwary, a trip to the auto dealer may begin as a bargain-hunting expedition, but end up as an expensive lesson in car shopping.
In this article, I’ll give you three important tips that you should use when shopping for your next vehicle. These tips will help you save money, save time, and negotiate objectively to get the best deal.
#1 – Set Your Emotions Aside
You visit the dealership lot and your eyes settle longingly on the gorgeous red automobile gracing the nearby pavement. You must have it, no matter the price. Slow down and take a breath. Buying a vehicle is a substantial investment. Unless you’re paying cash, you’ll be making monthly payments for several years. Will you feel the same way about the car three or four years down the road? Or, are you merely suffering from love at first sight?
#2 – Keep The Numbers Separate
If you’re hoping to trade-in your clunker to have the value applied to your new automobile, be careful. When it comes to numbers and amortization schedules, the dealer’s salesperson is king. Too often, prospective buyers will blend the negotiations. Predictably, the salesperson will offer what seems to be an incredibly generous amount on the trade-in. The buyer, reeling from his good fortune, practically falls into the seat of his new vehicle. Unknown to him or her, the dealer’s profit is built into the monthly payments.
Negotiate the transactions separately. Begin with cementing the price of your new automobile. Then, work on the value of your trade-in. That way, you’ll know whether you’re truly getting a good deal (on both transactions) or if you’re being taken around the block.
#3 – Shorten The Financing Terms
One of the strategies that auto dealerships are using in order to entice people into buying new vehicles is offering a 7-year loan. At first, it sounds great; a longer loan means lower monthly payments. The truth is, longer financing terms translate into a higher cost for you and more profit for the dealer. In other words, they’re not offering it to be nice.
If possible, say no to the extra long loan. Instead, opt for shorter terms that allow you to pay off the loan more quickly. You’ll pay less interest and when the time comes to sell your car, you won’t find yourself owing more than it’s worth.
Even though the car-buying landscape has shifted in favor of the buyer, you should still be wary of making a purchase decision too quickly. Remember, set your emotions aside, keep your trade-in negotiation separate, and avoid the extra long financing. By the time you leave the dealership lot, you’ll be confident that you weren’t taken for a ride.
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