3/5/7 angle valve jobs?

[Brummmie]

Ok, so whats the deal?
Is it more angles the better, or i suspect who is doing it that is a factor.
I am going to have my Dart LS heads done over the salted roads period, and i have been offered all of these options!!

[Brummmie]

sparkybean said:

Have always wondered this. Supposedly more angles are better, but this must mean that the best valve cut is a smooth circular seat (infinite angles etc), no?

but then what radius!?

[Brummmie]

Crikey! Remembering and rehearsing that lot, will be more prep than I did for me Cse's!

Thanks for the comprehensive reply.

[Brummmie]

I'm off to knight engine services nr silverstone with the heads today, while I'm there I will have the ITB's port matched. But I will go armed with a few questions now.
I'll Dyno it once the work is done anyway.

[Brummmie]

gsd2000 said:

Paul your not making all that power with pretty much standard as cast dart 205 heads?

They are 225 Dart heads, i took the combustion chambers out to match the larger bore, unshrouding the valves in the process and cc'd the chambers to get the comp ratio i wanted.
I also blended the bowls in and took the casting flashes out of the runners.
There lots more to have a go at though i think..

This is what i did last time, just a light clean up.

[Brummmie]

Hey, he uses a Sunnen one tick in the box! and he said without any prompting they are much betterer!

Edited by Brummmie on Thursday 15th December 22:25

[Brummmie]

Err...4?

[Brummmie]

Puma..

Thinning those guide bosses out and matching the throttle bodies must help out too?

I'll post up the results after anyway, i'm sure some people might be interested?

here is the pre operation results, these are at the wheels numbers.

[Brummmie]

The bosses are bog stock at the moment, given the heads are designed for an engine of 5.7 and mine is over 6.8, i'm going to take my chances!
They are 225cc runners and you can get them as 255+ for these strokers, i reckon it will be worth a go.

[Brummmie]

stevieturbo said:

Yes, but do the 255cc heads have reduced guides ?

Even on my old "stg3" ported RV8 heads. They still left full bullet nose guides in place, because shortening them made no difference whatsoever.

Agreed, dont want them shortened, but just thinking less metal in the way and a nicer shape?

This is a set Dart's that are their 245cc CNC jobbies,

[Brummmie]

Yes, and he joined on my thread!!

But what about me bloody heads?

[Brummmie]

Yep....

I give in.

[Brummmie]

Pumaracing said:

So all the punters got asked which port flowed the most and of course most of them plumped straight for the big hogged out shiny one. Then he put it on the flowbench and proved that the one that looked stock outflowed all the others by miles.

Scary!!!

You have answered more than i can comprehend

I'm scared witless now what i am going to get back, i'll be looking at what you have said and comparing, no doubt there will be differences.
Just was interested on comparing those two pictures i put up on the same casting.

Again Thankyou.

[Brummmie]

stevieturbo said:

Although a little more googling. Seems there are some ITB that dont cost the earth, even if they have short runners ?

http://www.extrudabody.com/servlet/the-170/Manifol...

Except that's only the manifold price....typical lol

These are mine on 55mm chokes, i am under the impression i need to keep the taper going to the valve to keep airflow speed increasing...but i'm probably wrong!
My valves are 51mm (2.02").

Edited by Brummmie on Tuesday 3rd January 22:43

[Brummmie]

Steve_D said:

Pumaracing said:

....The overlap of the trumpet edges might be hurting things a bit....

I think that may just be the way they are sat on the bench.

Steve

Correct, they are just on a pile on the floor!
They are Kinsler ITBs, all the linkages etc are too.

http://www.kinsler.com/page--Home-Page--13.html

[Brummmie]

Pumaracing said:

So Mr OP. Aren't your heads finished yet and some new bhp numbers to show us?

No, I am due to get them back this week, they have gone to be fitted up at the recommended valve spring height and one valve is too far out with the others, so has to be machined into the head 15 thou, so they all have 30 thou washers under the valve springs to give the right spring install.
i will post up whether good bad, or ugly!
Fingers crossed...

[Brummmie]

Took longer than antiscipated but they are back,





had the ports matched to the ITB's

[Brummmie]

Cheers Simon, i am now waiting on shims so i can install the springs at the correct height...

[Brummmie]

gsd2000 said:

Are they on yet?

Be running tomorrow with any luck, dyno Thurs/Fri with even more luck, and trackday next Sunday if lady luck gives me a BJ!

[Brummmie]

This is it, i want to just drive the thing now!