One of the most important factors in engine building is determining your engine s final compression ratio. Compression ratio (C/R) has far reaching effects on the performance of any internal combustion engine. If the C/R is too low, you'll have a real dog on your hands. Too high and you won't be able to run pump gas without incurring pre-ignition and destructive detonation. Ignore the C/R and you could be in for a very unpleasant surprise.

First we'll identify and define the components necessary for completion of a formula that determines C/R. You'll need each one of the bold type measurements to accurately determine your C/R. For this example, we'll use a 1970 Ford 385 Series 460 with 78cc cylinder head combustion chambers. For your engine, substitute the measurements from your components. With most engines, all specifications are available from your shop manual. All measurements are in inches.
#
D - BLOCK DECK HEIGHT = 10.322
#
H - COMPRESSION HEIGHT = 1.76
# L - CONNECTING ROD LENGTH = 6.605
# S - STROKE = 3.85
# T - CRANK THROW = 1.925 (1/2 OF STROKE)
# d - DECK CLEARANCE = 0.032

DECK CLEARANCE CALCULATION: Compression height (1.760) + connecting

rod length (6.605) + crank throw (1.925) = 10.290

Block deck, 10.322, minus 10.290 = 0.032 deck clearance

This calculation uses a standard dished 460 piston with a dish size of 12cc. If your pistons have valve relief cuts (eyebrows), dishes or domes, that must be included in the calculation as a cc measurement. Any piston manufacturer can provide this information and the piston compression height.

Cylinder bore 4.360

Head gasket compressed thickness is 0.040
Head gasket bore size is 4.460

Now that we have all the required measurements, we can put them into a formula that will give us the exact C/R for this engine:

Compression ratio = S.V. (swept volume)

----- + 1

C.V. (clearance volume)

Since most of are do-it-yourselfers and not engineers, we ll do it the easy way and go to one of the websites that allows us to enter our measurements and instantly calculates the actual C/R:

These are the actual measurements required for the suggested automated calculator on this application:

Bore: 4.360

Stroke: 3.85

Cylinder head volume: 78cc

Deck height clearance: 0.032

Head gasket bore: 4.460

Compressed head gasket thickness: 0.040

Piston dish: 12.1cc

Final compression ratio = 9.959:1

As you can see, thanks to Internet access, determining your actual compression ratio is no longer a task best left to machinists and engineers. This will help you to put your dollars to the best usage in building an engine.

I suggest utilizing one of the software programs currently available to determine what C/R is best for your engine combination. When you input all your engine's various components into the program, it takes the guesswork out of what C/R you should run by showing 'what if' results in torque and horsepower graphs. Then you can adjust your C/R with deck height, pistons, bore and stroke to fit your cam, ignition, and fuel delivery and exhaust systems.

Suggested Compression Ratios for Street Driven Engines

Anything under about 9.0:1 will not provide the most efficient engine and, naturally aspirated, is dog country.

With cast iron heads, 9.0-9.3:1 is considered the maximum C/R for regular (87 octane) pump gasoline.

10.5:1 is about maximum for today's premium (91-94 octane) pump gasoline with a cast iron head. And that's assuming you keep the rpms up without lugging the engine, you've cleaned up the combustion chambers of sharp edges and rough spots to reduce the possibility of pre-ignition and use a zero deck clearance, or close to it, to enhance quench.

Aluminum heads will generally allow 11.5:1 C/R on premium pump gasoline, again assuming you have clean combustion chambers and a zero deck clearance.

If you run A/C, take .5 off the maximums.

Note: This information is intended for usage in the calculation of internal combustion engine compression ratios and the author makes no claims as to its accuracy or warranties its usage by any individual or company other than the author.

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Regardless of the season, your Honda car must always be clean and nice because part contributes to the performance of the car as a whole. A well maintained exterior, aside from the good looks, is also a stepping stone in achieving your Honda’s consistently great performance.



You definitely would not want damage on your Honda bumper, windows or doors. A simple way of avoiding this is trimming down trees or shrubs that touch the surfaces of you Honda car.



Washing your car should be a habit, most especially if there is noticeable dirt or debris. At least once a month, let your car experience the washing it deserves. Things like bugs, bird's dropping, or limestone dripping deteriorate the paint marking permanent stains if not washed off in time. All the moisture quickly dries up when the car is clean. But when it is dirty, the moisture accumulates in dirty areas that cause corrosion. At least once in a while use a pressure wash. It really helps because it removes the dirt from difficult to reach areas. Make sure to wash off all the areas where the dirt and salt could be accumulated such as behind moldings, inside wheel arches, under the bumpers, etc. After winter, it is particularly helpful to wash out all the salt accumulations that rush the corrosion process.

Waxing your car regularly helps in protecting the paint, reducing harsh effects of chemicals and protecting the paint from fading. Additionally, the car looks shiny. It takes only about 30 minutes to wax a whole car but a high quality car wax stays on the car for three to four months. Any product needs to be reapplied periodically in order to maintain protective coat.

Undercoating and rust proofing your vehicle will also be a huge help especially if you live in an area with high humidity, or where the salt use is common in winter months. A part of the brake system located underneath a car may be completely rusted in just 5 years in a high humidity, coastal area. In the long run, one of the brake lines can burst and the car will have no brakes. Make sure to properly undercoat and rust proof your car to protect important components from corrosion.

Repairing stone chips as soon as possible is also necessary. If not repaired at the right time, it will cause corrosion. All you need is a matching spray paint and a tooth pick. But if you have touch-up paint with the brush, you can use it instead. For a few minutes, shake the spray paint very well. And then, spray very small amount into the cap. Slightly deep the end of the toothpick into the paint cap. After that, everything would be fine.

A well looking exterior of a Honda car is a huge determinant of being a responsible owner. Aside from that, you can be assured that your car will perform well and not look disgusting, thereby giving you comfort and pleasure while driving.

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Harley Davidson motorcycles are some of the most durable bikes on the market. They are built to last using high quality materials and craftsmanship. Therefore, the cost of a new Harley may be out of reach for some individuals.

Many people find that purchasing a used motorcycle is a better option. However, it's a good idea to possess a healthy dose of skepticism when purchasing a used bike; particularly from a private seller.

Previously owned motorcycles can be found through private sellers who oftentimes announce their offer via classified ads posted in magazines or online bulletin boards. Used motorcycles can also be found at authorized Harley-Davidson dealerships and public auctions.

# Authorized Harley-Davidson Dealers.

One of the safest ways to purchase a used Harley-Davidson motorcycle is through an authorized dealer. Along with financing options, many dealers offer extended warranties and optional maintenance services. They inspect the bikes for any potential problems and provide buyers with documentation that guarantees the used motorcycle is legal.

To find a list of authorized Harley-Davidson dealers visit www.hogs4sale.com. Click on the state you reside in to locate a dealer in your area.

# Online Classifieds.

There are several reputable websites that offer a wide range of used motorcycles. Ads are placed by private sellers and transactions are made directly from seller to buyer. Both buyers and sellers are required to create an account in order to communicate with one another. Upon registration, buyers can contact sellers via email to obtain information, arrange a meeting, and arrange financial transactions.

Care should be taken when buying or selling through online classifieds. While the majority of people participating are honest, you should thoroughly investigate the motorcycle and its history before handing over your hard earned cash.

Three of the most reputable online classified websites for used motorcycles include: www.CycleClassifieds.us, www.HD4Sale.com, and www.HarleyHunters.com.

# Online Auction Sites.

E-bay is one of the most popular auction sites for used Harley Davidson motorcycles. Certain precautions are required and buyers should thoroughly investigate the seller using E-bay's tools and seller rating system. If you use common sense and adhere to the information provided on E-bay's website, chances are excellent that you will have a safe and happy transaction.

Other used motorcycle auction websites include www.MotorcycleAuctionsOnline.com and Yahoo Shopping Auctions at http://auctions.yahoo.com. Before you begin shopping for a used motorcycle, it's a good idea to educate yourself about the makes and models of motorcycles you are interested in. Do some research to determine the average cost of the motorcycle in your area; investigate insurance and finance rates; and make a list of common defects to look out for.

When purchasing a used motorcycle through online classifieds or auctions, be aware of any claims that sound too good to be true. If you find a potential deal, physically review the bike before purchasing it.

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