ok thought it was time to update this thread. Progress is quite slow at the moment due to spending a lot of time on luigi my lil 126 however i decided to reignite some enthusiasm and crack on with porting this cylinder head.
Now it must be said right at this stage that a lot has been said (and criticised) about the dark art of gas flowing and porting cylinder heads so i just want to say that i am an amateur enthusiast and i am by no means saying that what i am doing here is going to give me any HP gains or massive torque figures, this is just an exercise in making the gases that flow through this head as efficient as possible to compliment the fast road cams that will hopefully be fitted
. i'm no race car builder but i am a firm believer that a smoother unrestricted bore will let gas flow though it a lot better than a rough bore with poorly matched components so with that in mind i gathered some tools and set to work.
the tools i used for this work are as follows..... an electric multi tool, an air powered die grinder, lots of little sanding bands, carbide cutting bits, a digital caliper, some emry cloth and some flap wheels...... oh and ALOT of patience!!
it has currently taken me about 12 hours worth of work to do just 4 inlet ports and this head enjoys 10 of them! so if you have any hope of pulling your head off on a Saturday morning gasflowing it and getting it running on a sunday afternoon then your gonna be disappointed!
part of the reason its taking me so long is because i'm taking it nice and slowly trimming bits of metal off and measuring then trimming some more. and once you've done say 3 i tend to go back to the first one to try and even them all out so there all measuring equally so its time comsuming to say the least.
this is one of the inlets BEFORE i stared any work. as you can see there a rough finish and the casting join can be seen going right down the middle. theres also a lot of oil staining in the ports so i must devise a better way of venting the oil fumes out of the engine.
digital calipers were used to measure various points in the bores. the measurement before the work was 46.4 mm at the opening of the inlet.
and 24.4 mm for the port throat leading to the valve head
This is the inlet AFTER reworking. a carbide cutter was used to rough it out then smoothed over with sanding bands, flap wheels and even by finger measuring every time to make sure it as equal as possible with the next one
the new measurement at the mouth is 48.2mm which is nealy 2mm bigger over the standard size. i got the other three to .1mm and eventually they will all be to that size
and the port throats are now marginally bigger too, again i got the 8 that i have already done to .1mm
and heres the other end of the valve throat in standard form - note that the shiny machined part is from the factory.
and again AFTER i reworked it. ive read all the books and researched the internet and it is here that power gains are to be had. valves and there chambers are quite disruptive to gas flow so ideally a 3 angled valve and seat and a reshaped valve throat is what is needed if horsepower is to be made but i wont be going down this route due to funding hence why i'm not promoting "high performance" gasflowing rather than efficient gasflowing
so we're getting there but theres still along way to go, i still have 1 more inlet then 5 more exhaust ports to do before i match them to the manifolds then clean up the combustion chambers!