Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Crankcase shopping experience:
1. Compare - without doubt the biggest advantage that the Crankcase offers shoppers today is the ability to compare thousands of Crankcase at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.
2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about
3. Testimonials - don't know anybody that has bought a Crankcase? Wrong! If the Crankcase is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.
4. Questions - Got a question about Crankcase then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....
5. Reputation - Never heard of the company selling Crankcase? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Crankcase and build up a picture of their reputation for sales, returns, customer service, delivery etc.
6. Returns - still worried that even after all of the above your Crankcase wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.
7. Feedback - happy with your Crankcase then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.
8. Security - check for the yellow padlock on the Crankcase site before you buy, and the s after http:/ /i.e. https:// = a secure site
9. Contact - got a question about Crankcase, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.
10. Payment - ready to pay for your Crankcase, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.
For the G.I. Joe character, see List of G.I. Joe ARAH characters.
In a
piston internal combustion engine, the
crankcase is the housing for the crankshaft. The enclosure forms the largest cavity in the engine, separated from the cylinder (engine)s by the reciprocating pistons.
Besides protecting the crankshaft and connecting rods from foreign objects, the crankcase serves other functions, depending on engine type.
Two-stroke engines
In
two-stroke cycle engines, the crankcase is sealed and is used as a pressurization chamber for the fuel/air mixture. As the piston rises, it pushes out exhaust fumes and provides a vacuum in the crankcase which sucks in new fuel/air. As the piston lowers, the fresh fuel/air is pushed from the crankcase and sucked into the cylinder. The Compression Stroke in Two-stroke Engines at
HowStuffWorksUnlike four-stroke engines, the crankcase does not hold the engine oil because it holds the fuel/air mixture. Instead, oil is mixed in with the fuel, and the mixture provides lubrication for the cylinder walls, crankshaft and
connecting rod plain bearing.
Four-stroke engines
In a four-stroke cycle engine, the crankcase is filled mainly with air and oil, and is largely sealed off from the fuel/air mixture by the pistons.
Oil circulation
Oil circulation is kept separate from the fuel/air mixture, thereby preserving oil rather than burning it as happens in two-stroke engines. Oil moves from its reservoir, is pressurized by an
oil pump, and is pumped through the
oil filter to remove grit. The oil is then squirted into the crankshaft and connecting rod bearings and onto the cylinder walls, and eventually drips off into the bottom of the crankcase. How Car Engines Work at HowStuffWorks In a wet sump system, oil remains in a reservoir at the bottom of the crankcase, referred to as the oil pan. In a
dry sump system, oil is instead pumped to an external reservoir. Why do some engines use a dry sump oil system? at HowStuffWorks
Even in a wet sump system, the crankshaft has minimal contact with the sump oil. Otherwise, the high-speed rotation of the crankshaft would cause the oil to froth, making it difficult for the oil pump to move the oil, which can starve the engine of lubrication. October 1996 question on Car Talk Small amounts of oil may splash onto the crankshaft during rough driving, referred to as windage.
In a wet sump system, the main dipstick and oil filler cap connect to the crankcase.
Air ventilation
During normal operation, a small amount of unburned fuel and exhaust gases escape around the
piston rings and enter the crankcase, referred to as "
blow-by". September 1999 question on Car Talk If these gases remained in the crankcase and condensed, the oil would become more diluted over time, decreasing its ability to lubricate. Condensed water would also cause parts of the engine to rust. January 2001 question on Car Talk To counter this, a crankcase ventilation system exists to draw fresh air in from the
air filter and expel the gases out the
PCV valve into the intake manifold. The intake manifold is at a
manifold vacuum than the crankcase, providing the suction to keep the ventilation system going.
If an engine is damaged or enters old age, gaps can form between the cylinder walls and pistons, resulting in larger amounts of blow-by than the crankcase ventilation system can handle. The gaps cause power loss, and ultimately mean that the engine needs to be rebuilt or replaced. Symptoms of excessive blow-by include oil being pushed up into the air filter, out the dipstick August 2002 question on Car Talk, or out the PCV valve.
References
For the G.I. Joe character, see List of G.I. Joe ARAH characters.
In a
piston internal combustion engine, the
crankcase is the housing for the crankshaft. The enclosure forms the largest cavity in the engine, separated from the cylinder (engine)s by the reciprocating pistons.
Besides protecting the crankshaft and
connecting rods from foreign objects, the crankcase serves other functions, depending on engine type.
Two-stroke engines
In
two-stroke cycle engines, the crankcase is sealed and is used as a pressurization chamber for the fuel/air mixture. As the piston rises, it pushes out exhaust fumes and provides a vacuum in the crankcase which sucks in new fuel/air. As the piston lowers, the fresh fuel/air is pushed from the crankcase and sucked into the cylinder. The Compression Stroke in Two-stroke Engines at
HowStuffWorksUnlike four-stroke engines, the crankcase does not hold the engine oil because it holds the fuel/air mixture. Instead, oil is mixed in with the fuel, and the mixture provides lubrication for the cylinder walls, crankshaft and
connecting rod plain bearing.
Four-stroke engines
In a four-stroke cycle engine, the crankcase is filled mainly with air and oil, and is largely sealed off from the fuel/air mixture by the pistons.
Oil circulation
Oil circulation is kept separate from the fuel/air mixture, thereby preserving oil rather than burning it as happens in two-stroke engines. Oil moves from its reservoir, is pressurized by an oil pump, and is pumped through the
oil filter to remove grit. The oil is then squirted into the crankshaft and connecting rod bearings and onto the cylinder walls, and eventually drips off into the bottom of the crankcase. How Car Engines Work at HowStuffWorks In a wet sump system, oil remains in a reservoir at the bottom of the crankcase, referred to as the oil pan. In a
dry sump system, oil is instead pumped to an external reservoir. Why do some engines use a dry sump oil system? at HowStuffWorks
Even in a wet sump system, the crankshaft has minimal contact with the sump oil. Otherwise, the high-speed rotation of the crankshaft would cause the oil to froth, making it difficult for the oil pump to move the oil, which can starve the engine of lubrication. October 1996 question on Car Talk Small amounts of oil may splash onto the crankshaft during rough driving, referred to as windage.
In a wet sump system, the main
dipstick and oil filler cap connect to the crankcase.
Air ventilation
During normal operation, a small amount of unburned fuel and exhaust gases escape around the piston rings and enter the crankcase, referred to as "
blow-by". September 1999 question on Car Talk If these gases remained in the crankcase and condensed, the oil would become more diluted over time, decreasing its ability to lubricate. Condensed water would also cause parts of the engine to rust. January 2001 question on Car Talk To counter this, a crankcase ventilation system exists to draw fresh air in from the
air filter and expel the gases out the
PCV valve into the intake manifold. The intake manifold is at a
manifold vacuum than the crankcase, providing the suction to keep the ventilation system going.
If an engine is damaged or enters old age, gaps can form between the cylinder walls and pistons, resulting in larger amounts of blow-by than the crankcase ventilation system can handle. The gaps cause power loss, and ultimately mean that the engine needs to be rebuilt or replaced. Symptoms of excessive blow-by include oil being pushed up into the air filter, out the dipstick August 2002 question on Car Talk, or out the PCV valve.
References
