Head porting and gas flow

[Aziz]

Hi guys

I might sound a bit thick but can anyone really tell me what is meant by PORTING and GAS FLOWING a cylinder head?

What is involved in this and can it be done easly

Cheers, Imram

[maxfield]

Proting makes head ports bigger.
Gas flow is making the ports making them smooth pretty much someone will probably go into more detail

[fuzzy]

i had this done to my cylinder head,i dont have a clue what it means either but im told i would expect a 15-20 bhp increase.it certainly makes it feel smoother and rev more freely.

[Aziz]

So

can this be done at home or is it a specialist job?

if it can be done at home what do I need to get the job done and what should I be looking for?

[maxfield]

So

can this be done at home or is it a specialist job?

if it can be done at home what do I need to get the job done and what should I be looking for?

It's probably a specialist job unless you've got the right machinary

[E30BeemerLad]

porting generally means making the size of the ports larger, usually using a dremel type device (usually air powered) to take the size of the ports (inlet and/or exhaust) so that the size of the ports on the head match the size of the inlet manifold and exhaust manifold. Thus allowing better flow.

Polishing the ports is simply taking away any rough edges and cast lines from the ports and sometimes also polishing the combustion chamber.

Depending on the engine concerned, sometimes polishing can actually reduce the power output of the engine as the rough edges on the inlet ports often held the mixture of fuel & air to swirl, creating better combusion.

There is a difference between a keen enthusiast attacking their cylinder head in the garage on a sunday afternoon and a professional doing it. The sad thing is there are few "professionals" who actually know what they are doing and what achieves genuine results.

This can only be seen from using a flowbench and also dyno runs.

[Jhonno]

flow bench wont always tell the whole story, gas speed is key..

[E30BeemerLad]

here's a pic of a 320 head which has had the ports taken out to match the size of 325 inlet

[Turbo-Brown]

Think porting is more about changing the shape of the ports than just making them bigger.

Getting them to line up with a manifold is just port matching.

If you want to have a go at home, I'd probably forget about "porting" as you're pretty unlikey to stumble accross the perfect port shape.

However, smoothing things off without taking off too much material with some coarse grade (like 80 or something) shouldn't harm things and might make an impovement

If you want a good job done, Dave Baker (who is PumaRacing) is well thought of and in great demand. Have a look at www.pumaracing.co.uk

[Ant]

on the M20 heads, unmasking the valves is the best way forward, have a look on the stcok items and you'll see whats what.

Agreed with Alex, smoothly does it for the DIY porting job, dont enlarge the ports as they dont need it, blended valve seats and the above mentioned tweak are all thats required IMHO.

Pinto porting techniques would be worth a gander, apple ported M20 anyone ??

[tonyppe]

if you want your head max ported, re-built, skimmed and gas-flowed i can get it done for a monkey.
the bloke did my fiesta, 1700 x-flow.

the induction noise through the twin carbs was mad

you could get two fingers down. well worth the money.

some poeple dont understand. if you got a 2.7 or whatever tuned to the nuts bottom end, lightend, balanced, u name it, and a mad cam. if you got a shit head thats even been done badly, your holding the car back.
you would probably be loosing tens of HP

[Turbo-Brown]

When you say you could get two fingers down, you can get two fingers down an 325 inlet port, doesn't mean it flows efficiently

It's all to do with port shape, not the size. Look at the Pinto as a good example of a head which people make the ports smaller on to increase power!

[fuzzy]

i dont think porting and polishing is something you should tackle yourself unless you know what your doing,best to leave to the professionals as i think its very engine specific,whats good for one type of engine might not be so good for a different one.ive spoke to different cosworth specialist,some recomend it some dont.