I would like to share a recent cylinder head I just finished. The cylinder head came out from a Mitsubishi Evolution VI with a 4G63 turbocharged 2.0L engine. The client came to our workshop complaining of severe oil burning and lack of power.
After we took out the head we found that the head had badly worn valve guides and digged seating’s and also we found out that the cylinder head was badly ported by a prior tuner compromising the durability hence the severe oil burning.
After cleaning, we made some testing on the in house Superflow flow bench and I went to the conclusion that the head needed some serious work to be able to make it better as the cylinder head was flowing less than an original standard head. What we did first was removing the standard cast iron valve guides, and had some special ones we use on the flow bench so we could test the flow after each porting modification. To solve the heavily digged seatings we decided to increase the valve sizes on both the inlet and exhaust valves by 1mm, to further try and make the port more efficient. After several hours the finished head was completely restored and flowing more than 30% more than when it came and i would like to point out that this was not a competition porting job but a street one and had to have full durability.
Below are some finished pictures and flow bench results.
Wednesday, August 12, 2009
Monday, August 10, 2009
Some More Cylinder Head Porting Background
The cylinder head is the most important part in an engine where substantial time and effort is spent by a professional tuner. There is more power to be gained in correctly porting the cylinder head than in any other modification that it can be done to an engine.
Cylinder head porting is the process of grinding material from the ports and chamber of the cylinder head to increase the airflow and thus improve performance of an engine.
The flow efficiency of the cylinder head will determine the horsepower potential that an engine can achieve and by correctly porting the cylinder head, higher level of efficiency is achieved and the engine will extract more power.
The cylinder head consists of three important areas which are the intake section, the combustion chamber section and the exhaust section. It is very important that all three sections are modified to work in conjunction with one another as power will suffer and engine efficiency will decrease considerably. I cannot stress this enough as every day I come across ruined heads after being ported badly and my point is that it is useless to have a huge high flowing polished inlet port and the combustion chamber is all shrouded and will not burn it efficiently or the exhaust port does not flow enough air or has a bad shape or the inlet/exhaust flow ratio is out as the engine will not produce more power or even worse decrease its power after being ported.
Another important topic is engine characteristics. Cylinder head porting needs to be accustomed to the usage that the engine will operate at. A head modified for drag racing operating between 7,000 and 10,000rpm will be useless to a rally engine needing more midrange torque and operating between 3500 and 7500rpm.
When a new client comes to our workshop with a cylinder head to have a porting job we ask several questions so that we can tailor the porting appropriately the type of driving the engine will operate in.
If the engine is going to be built in house then we know most of the answers but if a client come with just the cylinder head than we need to make sure to have all the required information so the cylinder head porting will be done accordingly.
Just to give you some idea these are some of the questions that we ask:
a)Is the engine for street use, off-road/rally, circle track or drag racing?
b)Is the engine normally aspirated, turbocharged, supercharged, NOS, or a combination?
c)Engine size, Bore, stroke, connecting rod length?
d)What type of fuel is going to be used? Pump fuel, racing leaded fuel, alcohol?
e)Is the engine carbureted or electronically fuel injected?
f)Will the car have a full exhaust system or open headers?
g)Is the camshaft still stock, and if not we need full specification.
h)What is the weight of the car and type of transmission and gearing is used? Manual, auto, sequential?
i.etc
After all the questions are answered then we can start the cylinder head analysis and port the cylinder head accordingly.
Next time we will post some information and pictures of a Mitsubishi Evo 4G63 turbo head we just did for street racing.
If you would like some help or require my service please contact me at cjpowertuning@yahoo.co.uk
Cylinder head porting is the process of grinding material from the ports and chamber of the cylinder head to increase the airflow and thus improve performance of an engine.
The flow efficiency of the cylinder head will determine the horsepower potential that an engine can achieve and by correctly porting the cylinder head, higher level of efficiency is achieved and the engine will extract more power.
The cylinder head consists of three important areas which are the intake section, the combustion chamber section and the exhaust section. It is very important that all three sections are modified to work in conjunction with one another as power will suffer and engine efficiency will decrease considerably. I cannot stress this enough as every day I come across ruined heads after being ported badly and my point is that it is useless to have a huge high flowing polished inlet port and the combustion chamber is all shrouded and will not burn it efficiently or the exhaust port does not flow enough air or has a bad shape or the inlet/exhaust flow ratio is out as the engine will not produce more power or even worse decrease its power after being ported.
Another important topic is engine characteristics. Cylinder head porting needs to be accustomed to the usage that the engine will operate at. A head modified for drag racing operating between 7,000 and 10,000rpm will be useless to a rally engine needing more midrange torque and operating between 3500 and 7500rpm.
When a new client comes to our workshop with a cylinder head to have a porting job we ask several questions so that we can tailor the porting appropriately the type of driving the engine will operate in.
If the engine is going to be built in house then we know most of the answers but if a client come with just the cylinder head than we need to make sure to have all the required information so the cylinder head porting will be done accordingly.
Just to give you some idea these are some of the questions that we ask:
a)Is the engine for street use, off-road/rally, circle track or drag racing?
b)Is the engine normally aspirated, turbocharged, supercharged, NOS, or a combination?
c)Engine size, Bore, stroke, connecting rod length?
d)What type of fuel is going to be used? Pump fuel, racing leaded fuel, alcohol?
e)Is the engine carbureted or electronically fuel injected?
f)Will the car have a full exhaust system or open headers?
g)Is the camshaft still stock, and if not we need full specification.
h)What is the weight of the car and type of transmission and gearing is used? Manual, auto, sequential?
i.etc
After all the questions are answered then we can start the cylinder head analysis and port the cylinder head accordingly.
Next time we will post some information and pictures of a Mitsubishi Evo 4G63 turbo head we just did for street racing.
If you would like some help or require my service please contact me at cjpowertuning@yahoo.co.uk
Monday, August 3, 2009
Great Cylinder Head Porting Info:
I would like to share some great information I use when porting my cylinder heads. Some time ago I came across a great package of nine great cylinder head porters and have shared their knowledge on a 10 CD package. This is a must have for the serious enthusiast and more for the professional head porter.
The name of the product is AirFlow Experts and is available in here.
Some of the subjects covered:
- What are your core beliefs on air flow?
- How do you get the most out of a head?
- How do you shape the all important short turn?
- How would you design a port from scratch?
- How do you calculate the following?
- Valve size needed
- Port size needed
- Window size needed
- Bowl size needed
- Seat ring ID needed
- Where are the biggest airflow restrictions?
- Differences in porting the intake port and exhaust port?
- Take us through the steps you take when porting a head.
- What are your favorite airflow formulas?
- How does porting a four valve head differ from a two valve?
- Air Flow Testing Tools:
- Flowbench - Best? Cheapest? Building your own?
- Diagnostic tools (flow balls, pressure probe, velocity probe, etc)
- Getting accurate results
- Duplicating your work (Templates, gauges, et)
- Modifications - Area Specific:
- Gasket - Area? Shape? Height?
- Pushrod - Area? Width?
- Roof - Width? Tip? Angle?
- Floor - Width? Tip? Shape?
- Walls - Shape?
- Window - Area? Shape?
- Short turn - Height? Width? Corners? Radius?
- Bowl - Width side to side? Width front to back? Depth? Shape?
- Guide - Shape? Height?
- Seat - Shape? Transition to bowl?
- Combustion chamber - Squish side? spark plug side? valve shrouding? Shape?
- Valves:
- Diameter - How do you decide?
- Face - Angle? (45', 55', etc) Width?
- Back cut - Angle(s)? Width?
- Shape? (Nail, Tulip, etc)
- Fixing flow problems:
- Poor low lift - What areas to focus?
- Poor mid lift - What areas to focus?
- Poor high lift - What areas to focus?
- CFM backs up at upper lifts - What areas to focus?
- Turbulent (noisy) - What areas to focus?
- Reverse flow - How to test? What to do?
- Swirl - What is it and how do we use it to improve power. You might be surprised by his answer
- Epoxy - When to use?
- Welding - When to use?
- How to get the most out of engine simulation software
- I hear Winston Cup teams are using Extrude Hone in a different way, what are they doing? This was a real eye opener.
- The biggest head porting mistakes you've seen?
- Current trends in porting?
- Biggest discoveries you’ve made working on cylinder heads?
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