head help

[sparkie]

need some help.
now got the cams and was wondering what is mean't by playing with head. a term my brother used. skimming it port and polsihing and gas flowed. what does all these mean.
also now looking for a lighted flywheel and some to get the car ecu remapped and then dyno tested.
any help would be gratefully recived.

 

[NeX]

its mainly opening all the spaces in the engine so that more fuel/air water etc can get through...

 

[59 bhp is more than enough]

i think your bro was on about something else.

there are holes in the "head" or tunnels if you will. these are inline with the valves so air come in your inlet and through the air part of these tunnels and in through your valves. combustion occurs then the exhasut gas is pushed out the exhaust valve and through another one of these "tunnels" into the manifold, down the exhaust etc.

porting the head is a term used to describe making these holes bigger so more air can flow through them, polishing means that these holes are nice are smooth so the air can flow through them easier. polishing is pretty much essential after porting coz your left with a very uneven rough surface that isnt good for air flow. skimming is a term used to describe milling a layer from the bottom of the "head" this is basically done if the head has warped and you want it flat so you get a good seal with teh gasket etc and also if your building a high tuned N/A engine then this can be done to lower compression (btw why do you want low compression for more power i cant figure it out)
not sure on the gas flowed part but im pretty sure that they need what is called a "flow bench" to make sure that all the gasses can flow correctly once the head work has been done.

hope this helps, no doubt someone will correct me but hey!

 

[59 bhp is more than enough]

oh yeah forgot to mention that with the cams in you will make better use of all the head work. and you will definalty need an ecu remap (micra pete will be doing these soon) or piggy back system that lets you alter timing as well as petrol/air mix. or you could get a "stand alone" ecu that lets you alter and tune pretty much everything that is plugged into your ecu normally. these however are very expensive.

 

[Moschops]

Skimming the head raises compression as it makes the combustion chamber smaller so the gas is squeezed into a smaller space. Fitting a thicker head gasket would lower compression.

I heard that polishing isn't vital as long as the ports are smooth and flow the gas efficiently. There's probably more gain to be had with matching the ports to the manifolds/gaskets. Maybe current wisdon is different tho. It's a long time since I did any head work