Modifying Keiths Nova head (pics)

[S_Gault]

http://www.reallymeansounds.com/forum/viewtopic.php?t=20780

Steven

[Dpnova]

it asks me to log on

[NovaNeil]

Me to

[mikeyredtop]

Modifed inlet port
http://www.reallymeansounds.com/forum/files/mod_inlet2.jpg
http://www.reallymeansounds.com/forum/files/modified_inlet_throat.jpg
stdrd inlet port
http://www.reallymeansounds.com/forum/files/std_inlet.jpg
http://www.reallymeansounds.com/forum/files/std_inlet_throat.jpg

[MC]

How many angles are on that valve seat, it's a little blurry.

I see the guides been taken down, vauxhall guides are very long so they can take it whereas some VW are too short as standard.

MC

[mikeyredtop]

heres bills head he doesnt touch the valve guides...
http://img11.photobucket.com/albums/v34/mikeyredtop/biller.jpg

[S_Gault]

ive been asked in past to do ones to Bills spec.. it takes all of about 2 hours! as opposed to the 20+ it takes to do it right.

Guess thats whu he makes money and i win championships.

Steven

[rgv_stu]

heres the head i did for my car last year - still aint got round to fitting it yet :lol:

i trimmed down the guides dunno wether that was wise or not only time will tell...just looked better for flow though...

http://uploader.co.uk/images/103-0311_img.jpg

http://uploader.co.uk/images/103-0316_img.jpg

http://uploader.co.uk/images/100-0079_img.jpg

thats a 1200 head , the 1400 sr head i did seemed to make a difference to the car after i fitted it :) so hopefully this 1200 head ought to make a good difference

[S_Gault]

you did the right thing as the flowbench shows a similiar improvemnt at low lifts as using a waisted stem valve.. but you have to modify the back of the standard valve to get a real good improvement.

Steven

[m.d.]

you can run your head like that with the guides wasted away but you will get serious wear on the guide itself so the best thing to do is get a new set of guides fitted that are thinned down or shorter than standard.

[S_Gault]

sorry but no..the guide is longer per unit length of valve stem than those in N/A cossies that i do.

Its f=got everything to do with rocker geometry and vlave lift of the cam.

Steven

[nova_rally]

Dumb question time: what do you use to cut the ports like that? I've got time to waste before the 1.2 head goes in and a 1.4 head to practice on so why not learn a new trick....

Alan

[S_Gault]

tunston carbide cutters in a die grinder.

I use a 60deg one for the valve seat inserts and a oval for the port (but they dont need any real metal removed, just a tiny reshape. I use a flame shaped one to get a nice radius on the short turn.

Then finish with emery bands.

For chambers i use a small sphere cutter.

The trick is knowing the sizes to make things, and unless youve a flowbench, you'll be guessing. Especially in the valve throats.

Steven

[j1400]

heres bills head he doesnt touch the valve guides...
http://img11.photobucket.com/albums/v34/mikeyredtop/biller.jpg

Isn't that a SPi head, the inlet lookslike it.

[nova_rally]

Cheers! I think I've got most of them, but I doubt I've got Tungsten-Carbide ones, more likely some kind of silicate. Should be alright on alloy though.

I'm only going for a slightly less restrictive flow behind the valve head, don't really want to mess too much!

Do you do anything to the exhaust ports?

Alan

[S_Gault]

very little is done to the exhaust port,

but the vlave seat insert and throat is extensively reworked. It is very undersized in std form. If you do this by hand, you will most likely go eccentric with the guide, it needs to be concentric otherwise you end up with a narrow width on the bottom cut on one side and a wide cut on the other. It just doesnt work.

The short turn on the std exhaust has a really bad sharp edge, this needs removing and radiusing into the floor for and into the bottom cut of the valve seat. Done correctly this picks up flow everywhere in the lift curve.

Steven

[m.d.]

i used a round steel bit for the whole lot on mine and just used loads of wd 40 to stop the ally from sticking to the cutter.
ill get a pic of mine up for the 2.0 if i can later.

also DO NOT! polish anything. just use a bit of emery to smooth things out a bit. polishing causes the fuel to fall out of suspension in the mixture and wont ignite properly. (according the vizard's book on modifying heads)

[j1400]

I was under the impression it's a good idea to polish the exhaust side to help keep reduce the ehat disapatingin to the head, although it all gets sottty pretty quickly.

[MC]

Does Bill only spend 2 hours modifying the cylinder head?

Will you get a better finished result spending 20 hours?

MC

[CP]

ive been asked in past to do ones to Bills spec.. it takes all of about 2 hours! as opposed to the 20+ it takes to do it right.

Guess thats whu he makes money and i win championships.

Steven

Check your PM's Stephen

:?: Just to put the other side - my personal opinion is that Bill does high quality work that many people are happy with. He doesnt rip people off by charging a lot to do sub standard work as implied above. Most of his recent work has been directed towards road cars not competition stuff.

[nova_rally]

Cheers for the input people, I feel a spate of Cylinder heads flowing my way now for practicing on! If one eventually makes its way into the rally car then It can be given a proper testing!

Alan

[S_Gault]

Why do i bother ...

[Will]

meaning?

[S_Gault]

i tell you the truth and poeple chose to ignore it..

Not just this.. in general- for example- im mapping a wee engine at minute and its pinking its bolts off.. customer tells me its got nothing to do with the fact his compression is about 14:1.. he read ity on the internet, so its bound to be right.. he says its my management system!!

Steven

[Stuart]

lmao, how do you get that thing to stop? it must diesel away like a demon lol

[S_Gault]

yea.. ive the head off and sump off and am machining the pistons this afternoon!

Steven