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IN ALL OF THESE CATEGORIES WE HAVE CREATED WINNERS AND CONTINUE TO, YOU CAN TO!

CNC Head Porting & Why Its Done

0 xxxxCNC head porting by RCS (Race Car Service of America), a method of machining the intake, exhaust ports and combustion chambers of an Automotive Cylinder Head. The purpose of this is to decrease the time it takes and to increase the accuracy in machining from port to port and cylinder to cylinder. Experienced professional cylinder head porters in the past and still today hand grind and shape the intake, exhaust ports and combustion chambers. The reasons, to increase the air flow rates traveling through the cylinder head, resulting in port increase size and shape changes. The increase of air that travels through the ports is the largest reason for Horse Power gains in the automotive combustion engine. The Automotive engine can be looked at as an inefficient air pump, increase the pumps air intake efficiency and you will increase the engines power out put when all is relative, as a rule of thumb for every 10% increase of air flow you can see a 10% increase of power out put. Hand porting can take hundreds and hundreds of man hours and the ability to be consistent from port to port is were the skilled hand porter works the hardest for each port must match in flow values both at peak and low lift flow rates, as well as port volume. A good head ported can make each port flow the same flow rates, at the same valve opening, in all the ports making them equal, but this can take hundreds of hours and is very hard work. This is why CNC Head Porting has become so popular in the racing industry and now is becoming popular with the street performance enthusiast as well. Understand this, you must still modify the existing ports of the cylinder head by hand and this still requires a great head porter that understands how air works in the combustion engine.

0 xxxxJust because someone has cast a head out of aluminum or cast iron doesn't mean that it is a good head. Just because a head is CNC ported, this does not mean that it's a good cylinder head, either by hand or by CNC both can be good or bad. You have to copy (digitize) a hand ported port to create a CNC machined port, so if the hand ported port is not good, then the CNC port will also not be good. Purchase your CNC or hand ported heads from a company ports their own heads and also builds their own custom engines, all different types of engines for they understand flow and port volume relations that is required to build fast running street and race track engines.

0 xxxxAt RCS the knowledge never leaves us, for we have CNC Programs for just about every popular head in the industry and if we don't we'll make one. For the advance engine shops this technology is going to become available from RCS as a CNC Porting package, including Fixtures, Tooling, Computers, Programs and CNC Machines for the shops that want to do their own machining, Call for this information.

0 OEM Cylinder Heads

0 xxxxThe most common type of cylinder heads that are CNC ported is the newer style performance casting's for the hard core Performance Race Engines. The most popular styles of cylinder heads ported in the average Performance Engine Machine shops are the standard OEM style heads (Original Equipment). This has been a popular trend also at RCS for years and has been our success porting theses heads and installing them for 28 years. Our engine customers know we can port their heads if necessary and be successful at giving the customer the power level their looking for from their own OEM cylinder heads. For example, your 5.0 Ford Mustang with OEM cast iron heads, these cylinder heads can be modified to make over 500 hp with hand porting in our engine shop, but when treated as a street performance head, can give a quick 150 hp with an enormous amount of acceleration, which is what a street performance engine must have. You will also need to do a camshaft design change with a slightly larger duration. By using the castings you currently own, lowers the cost of the performance head(s) project by 50%, not to mention the port volumes are smaller on the OEM castings, which will increase the acceleration of the engine. Large volume intake ports KILLLLLLL accelerating HP in all engines, but more so in smaller engines or engines that are engineered to be driven on the street in need of a wider power band. What you feel when setting in the drivers seat of your car, hard on the throttle, is accelerating horse power not steady state Dynamometer tested horse power, this is a power that can not be measured on an Engine Dynamometer or Chassis Dynamometer, this is measured by time over distance like being at a 1/8 or 1/4 mile Drag Racing Track.

0 xxxxThe reason you do not see head porters CNC porting OEM cast iron is that the ports are to small and the work that is required to program these small ports is to hard, plus the heads are cast iron, very hard to machine with any speed, hard on cutters and in short they can't make enough profit. If you notice every body is selling the same thing, after market aluminum cylinder heads, every shape and form, good or bad. A cylinder head caster or most high volume cylinder head companies are not true engine builders and lack the many years experience (knowledge) that the street or street/race engines require. They do not understand the intake manifold system or fuel system that you have and don't care, for they are selling air flow numbers. When's the last time you saw anyone race a flow bench or win with a dyno? We don't race or drive flow benches or dyno's!!! They are tools for measuring, equipment that we use to compare steady state data which may not adversely affect what the engine wants to make it make more power and or accelerate fast.

0 A Quick Story

0 xxxx1972 Camaro, 413 HP, 446 ft trq - 406 s/b Chevy with a dual plan Performer intake and 750 cfm vacuum secondary carb, 3 speed Automatic with 2,400 stall, 3.73 gears, Hi flow exhaust, 8" wide tires in the rear. This car should really run and spin the tires for ever on the street. We built this engine combination many years ago when we were learning, we read magazines and performance tips from all the different companies like GM. We no longer read performance magazines or take anyone advise anymore, for most don't know what the hell is going on, all they give is their unsupported opinions. GM states in their performance books as many other aftermarket product manufactures do, they sell a dual plane intake with the middle divider lowered 1 inch for increase power across the power band. Again I state "we do not drive dyno's". This engine was short by 3 hp from making 400HP and the customer wanted 400 plus. We removed the intake and machined the divider lowered to 1" x 2.5", reinstalled the intake set everything and we then made 413 HP, this was great, the customers happy, we're happy. We install the engine and road test the car, we were happy, but not impressed. The car had no hard charging low end power, twenty feet out it ran like a rabbit, but only spin the tires about 10 ft only when you really launched the car hard. We worked with the vacuum secondary, discharge nozzles, everything, to try to get the car to launch harder, we gave the car to the customer and soon the customer returned, quote;

0 "I'm not happy" That was the last time I ever heard a custom say that to me again!!!!

0 xxxxThe customer stated the car doesn't spin the tires enough and I want the car to spin the tires hard. No problem I said, we then removed the intake manifold and welded up the divider and reinstall it. Our property frontage is over 100 ft long, from one end to the other the tires were smoking all through first and second hang on what a ride. Don't believe everything you read, even from GM. The jest of this story is that the engine dyno and or flow bench are only tools for measuring and are not to replace experience and track testing. In this case the air volume under the carb in the intake was to large for hard throttle, combining the two sides of the intake manifold together slowed down the air velocity and signal this engine created that is needed to pull on the carburetors fuel metering system which if not there, then leans out the fuel mixture at lower engine speeds, opposite of what the engine really wants at this point a richer fuel cure. At low engine speeds, this will starve the cylinders of fuel mixture and not allow the engine to produce the power it is capable of making.

0 xxxxWe have learned over the years that all the cylinder heads sold in after market, the port volumes are to big, Why? Anyone can make a large port flow air and air flow numbers is what they are selling. If your engine could talk, it will tell you smaller, I want my ports smaller. Believe me your engine can speak to you, but in another way it just won't make any power, read the signs, where does your engine come alive, what part of the power band.

0 xxxxThe problem with Performance After Market and some early OEM cylinder heads is that their port volumes are too large for the amount of airflow that they flow. This becomes a problem for the street performance engines and makes a lot of customers that purchase heads or engine parts through Mail Order companies very unhappy. Acceleration is what we are looking for, settle for nothing less when designing an engine. This is the black art of engine design for with acceleration comes, fuel economy, throttle response, faster 0-60 MPH speeds, cleaner burning combustion and higher Dynamometer tested power. This is what good Performance Engine Builder push to achieve. This can be achieved through Mail Order business only if you are either lucky, you have found a salesman that has experience and or you can copy what has been already designed and proven. The problem with Mail Order is that if the part doesn't work for you, you've used it and you can't return it and the funds you allocated for your project is now spent and your stuck with the out come. Performance Magazines can also be miss leading if the information is made to impress the public and sell magazines and products, most magazine companies do not represent or support the information they print.

0 What to expect from OEM Heads

0 xxxxThere are cylinders heads from the OEM industry that make great horsepower when prepared by an expert head porter. RCS has ported OEM cast iron HEADS for engines that have made up to;

0 CHEVY- OEM heads to 850hp

FORD - OEM heads up to 750hp

CHRYSLER -OEM heads to 750hp

AMC -OEM heads up to 650hp

BUICK-OEM heads to 600hp

PONTIAC -OEM heads to 650hp

OID'S-OEM heads to 550hp

xxxxWe know these HP levels are possible for we Dyno tested each of these combinations. This does not mean that these are the highest possible power values, just where we have been under certain conditions. These were all cast iron cylinder heads from your factory style engine that were all driven off the show room floor. Most of these OEM castings are cast iron and cost a little more to port, because of cast iron. The option of CNC porting these cast iron beauties is growing. Aluminum is the most popular request and most serious race engines owners want because of the difference of weight, repairability and new technology, but Cast Iron vs. Aluminum, Cast Iron Heads will yield more Horse Power when comparing two equal heads, that's a fact. When you have a budget and already own one of these greats you can produce a wonderful amount of power, enough to turn anyone's head at the track. The option of maximizing out your heads is not always necessary for you can make all levels of power from these types of heads. Anyone can pick up the phone and buy a mail order aftermarket head and be just like a lot of the other people out there, but blow your friends mine when your OEM sleeper kicks there butt. Good luck! We have done it so many times.

RCS also sells all the cylinders heads in the industry and can port any cylinder head in the industry to match the customers needs.

0 Mail Order Cylinder Heads

xxxxNot all cylinder heads are equal, just like not all mines are equal, why would a person by a cylinder head from a company that only brokers Cylinder Heads and does not specialize in using them on Engines that they build and sell. For there are only a few companies that make Cylinder Heads, the rest are brokers of the industry. The company selling Heads must truly understand what is needed from the cylinder head when choosing for the complete engine requirements, one must look for a company that does both, Cylinder Head and Engine development together. From the customers view point the real test and answers come from putting the heads on and testing them yourself, at your own expense, there's no returning them if your not happy or if the power band is poor at low speeds and the car lacks accelerating HP and now requires 4.10 or higher gears to make the car perform. The more accelerating power an engine makes the less gear is required, think of this, some Pro Stock Drag Racers us a 3.90 rear axle gear to go over 220 miles per hour in the quarter mile. Cylinder Heads are the most important part along with the correct camshaft when building the power band of your engine. This is an area of the engine that a customer or engine builder should not over look or take for granted to be adequate. Some engines that have lower engine power on the Dyno have great accelerating horse power due to the correct intake manifold, cylinder head port volumes and camshaft, not cylinder head advertised flow rates. Price should not dictate your decision when choosing a cylinder head, the more time and parts that go into a project warrants a higher price, every shop works almost at the same labor rates or we wouldn't be able to stay in business. The cost differences come from how much work is going into the product with the quantity and quality of parts used, which will yield a better product and performance for the customer. The reason a customer sees so many Cylinder Head Shops selling the same stuff, Cylinder Heads are little in size, are easy to handle, can be bought from the manufacture assembled with out any additional work required for the average and require no liability on the seller's behalf for their intended use and require no guarantees on power out puts. Do business with cylinder head companies that can prove the parts they sell from their personal experience and not by what is read in a magazine. The industry is like this for there are no Engineering Standards to follow in the after market and that is why there are so many companies that representing another companies products. Give us a call on your Cylinder Head needs 1-888-881-1012.