B18c Head Porting

[B18cEG]

Hey everyone, can anyone tell me who there is that can do a port/polish for my b18c head but doesnt cost a hole heap, i already have dual valve
springs and titanium retainers and can get oversized valves if they think it will be better.

ALSO IT WOULD HELP IF ANYONE IS ABLE TO PROVIDE ME THIS SERVICE IN EXCHANGE FOR ALPINE OR ROCKFORD OR SIMILAR CAR AUDIO EQUIPTMENT OF ANY SORT BRAND NEW WITH RECIEPTS, DECKS, SUBS, AMPS, SPLITS...


Just give me a PM or whatever

Thanks people

[grumpy rooster]

Do you want to stay local or willing to come over East?

[B18cEG]

Do you want to stay local or willing to come over East?

Which ever way, i dont mind

[fatboyz39]

Pm if you want a B18c head ported.

[B18cEG]

Hey guys, just wondering what the cost is to just polish the intake and exhaust ports?

[Benson]

Why polish?

[B18cEG]

Why polish?

When you port why do you polish??
To reduce turbulance or are you one of those that says the intake port should not be polished?

[creativepunka]

When you port why do you polish??
To reduce turbulance or are you one of those that says the intake port should not be polished?

The intake ports dont need polishing, it improves fuel atomisation.

[B18cEG]

The intake ports dont need polishing, it improves fuel atomisation.

Sorry to tell you but alot of us are running fuel injection now not carby, the reason alot of people dont or didn't polish intake is because when they ran carby both air and fuel had to run along the runners which could cause fuel to stick to the side walls of a smoothly polished port, but as you may realise only air is traveling through until the very end where the fuel is squirted almost directly into the combustion chamber, greatly minimizing the chance of this happening. please correct me if im wrong

[fatboyz39]

Sorry to tell you but alot of us are running fuel injection now not carby, the reason alot of people dont or didn't polish intake is because when they ran carby both air and fuel had to run along the runners which could cause fuel to stick to the side walls of a smoothly polished port, but as you may realise only air is traveling through until the very end where the fuel is squirted almost directly into the combustion chamber, greatly minimizing the chance of this happening. please correct me if im wrong

Why does a golf ball have dimples on the surface of it ?

[TODA AU]

Why does a golf ball have dimples on the surface of it ?

So that it flies higher, longer & straighter than a smooth ball.
That is, when struck correctly with a spin imparted, the aditional surface area affored by the dimples allows the ball to act as an airfoil.
This has little or no relevance to cylinder head porting as spinning airflow over lumps or dimples behaves differently to laminar air over a spinning object.

B18cEG is right, smooth ports have improved flow,
I doesn't really need to be polished, but it should be smooth.
Though the shape is more important that the actual finish, if the finnish wasn't important, why do you suppose Honda went to the trouble to develop a special technique for producing the ports in NSX heads, now used in the new FD2 CTR ?
The end result is a port finish that is deliberatly smoother than normal.

[fatboyz39]

So that it flies higher, longer & straighter than a smooth ball.
That is, when struck correctly with a spin imparted, the aditional surface area affored by the dimples allows the ball to act as an airfoil.
This has little or no relevance to cylinder head porting as spinning airflow over lumps or dimples behaves differently to laminar air over a spinning object.



Currently the best flowing cyl heads around are CNC ported and these use a rough texture on the surface and not a polished surface hence my reference to the golf ball

By using a rough surface you create what in the industry is called tumbling and this in turn creates better cylinder filling as from what I read somewhere swirl as the air passes thru the valves and into the combustion chamber hence creating better cyl fill,but what would I know I am just a guy behind a keyboard .

[TODA AU]

Currently the best flowing cyl heads around are CNC ported and these use a rough texture on the surface and not a polished surface hence my reference to the golf ball

By using a rough surface you create what in the industry is called tumbling and this in turn creates better cylinder filling as from what I read somewhere swirl as the air passes thru the valves and into the combustion chamber hence creating better cyl fill,but what would I know I am just a guy behind a keyboard .
The most consistent flowing cylinder heads are CNC ported,
That said, they’re only as good as the hand ported original that they are modeled off.

Regarding the texture,
You’re right; it’s not smooth as in polished, but it is smoother than a general cast finish.
More to the point, it doesn’t have dimples applied as are found on golf balls.

Regarding air flow in ports,
The swirl imparted to air flow as it passes through the valves is a product of the port shape.
The lower the port angle & the sharper the turn into the chamber, the faster the spin imparted.
Further, the spin through each intake valve (4 valve) is in the opposite direction to each other.
This imparted spin due to shape of the port can be affected by the surface finish of the port.
If the air flow through the port is laminar & able to spin as intended through design / shape of port,
The less interference imparted to the boundary layer airflow, the better – that is more air into the cylinder for a given engine cycle.
Whether or not the air flow is laminar or turbulent can be calculated using the “Reynolds Number”
This is all public domain information & found in most uni text books. – Fluid dynamics.

[krogoth]

mmmmmmmmmmm

very interesting

im learning all this shit now....does my head in..

[z3lda]

mmmmmmmmmmm

very interesting

im learning all this shit now....does my head in..

ozhonda is not the place to learn things

[krogoth]

i meant im learning this at uni, not here, lol

[180sx]

how much does port and polish cost normally? say on B16a head?

[grumpy rooster]

It depends on who is doing it and what they are doing. Its like anything, you get what you pay for. :)

[revNhevN]

Lol. Reynolds Number. From what i remember from fluid mech, this is a bitch to calculate.

[creativepunka]

Sorry to tell you but alot of us are running fuel injection now not carby, the reason alot of people dont or didn't polish intake is because when they ran carby both air and fuel had to run along the runners which could cause fuel to stick to the side walls of a smoothly polished port, but as you may realise only air is traveling through until the very end where the fuel is squirted almost directly into the combustion chamber, greatly minimizing the chance of this happening. please correct me if im wrong


You still have a good 2+inches from the injector to the valve. If you look at glass when it rains you can see how it forms beeds that tend to sit for a while, these can cause a slight fluctuation in A/F ratios., on a matt type surface this does not occur. Im not talking about dimples or anything, i usually hit it with the sand blaster and leave that as the final finish.