Building up a mean F head

[Billzilla]

Yeppers to the previous two posts.

[Sam_Q]

whats that mean bill? am I way off?

[Billzilla]

whats that mean bill? am I way off?

Nope, spot-on mate.
The only things the 20v heads have going for them is a pretty good inlet port and slightly tighter included valve angle. The inlet manifold is also excellent.
Those two factors makes them better than the 16v head, but the rest of them (three inlets, poor squish, small buckets, etc) really hurt them.

[ed]

fwiw, i makes me squirm to see a pic from a "what year is that" f1 patent document compared to production engine end product. what exactly are we looking at? port orientation only? could tell you that without the pic...

apple, apple, cantelope

[Sam_Q]

I heard what your saying ed and its a valid point. Ok what I wasnt trying to show is that this is a F1 engine and therefore this digram is exactly what is the optimum setup is for an internal combustion engine. I tried to source the origin of this pic and I couldnt, and as you hinted it could of been of any year. The point of me posting it was twofold: first up it was to show that regardless of the year this engine came from I think I can pretty safely say that it would of had a higher kw/L than anyone of use will ever acheive (without boost or N2O) and it still has a narrow valve angle. So therefore the whole narrow valve angle means it just cant make power is BS. Secondly how it is is as you said: port orientation and how the FE head clearly is a better design in its intake path than a 4age. I guess I should of made myself clearer earlier.

and as always I am open to correction

[Sam_Q]

Oh also Bill a quick one for you, what head studs/bolts can be used on a late F head? is it the same deal as a 20v where 2 x 16v sets are needed?

[Billzilla]

Oh also Bill a quick one for you, what head studs/bolts can be used on a late F head? is it the same deal as a 20v where 2 x 16v sets are needed?

I'm pretty sure they use the same length as 16v 4AGE. I've got a set of ARP 16v head studs to go into my engine anyway.

And your previous post was also correct - narrow angle is better than wide angle, and that F1 head is at least early 90's onwards.

[Sam_Q]

ok thanks bill that saved me some trouble in finding that out.

[Mr Revhead]

if narrow angle is better....
why the switch (and continued use) of wide angles?

[Sam_Q]

who is still using wide angles? are you refering to a 2zz-ge?

from what I read just about all motorbikes are using narrow angles now as with all designed and built from the ground up race engines.

[oldcorollas]

you'll find bikes, and higher end race engines also have short strokes.. requiring smaller combustion chambers.
perhaps there is a balance between the valve angle.. and trying to avoid a highly domed piston that could interfere with combustion paths (splitting chamber etc).

if you have 30mm stroke (for arguments sake), having a combustion chamber domed by 20mm may not help.

[Billzilla]

if narrow angle is better....
why the switch (and continued use) of wide angles?

Because not many manufacturers build engines properly.
Dunno why.

[Mr Revhead]

im no expert...

but i think theres more to it than simply narrow is better.
ie oldcorollas suggestion?

its just very weird that for all these years ppl like cosworth, ford, toyota, honda, chev etc etc have all been wrong.

im not outright saying your wrong bill, im just not understanding as to why its better!
i shall do more reading...

[Ben Wilson]

The narrow angle heads produce all sorts of packaging issues if you want to make good horsepower. Manifolds coming out of a motor upwards makes it really hard to get the nice low bonnet line the aero guys want..

[Sam_Q]

you'll find bikes, and higher end race engines also have short strokes.. requiring smaller combustion chambers.
perhaps there is a balance between the valve angle.. and trying to avoid a highly domed piston that could interfere with combustion paths (splitting chamber etc).

if you have 30mm stroke (for arguments sake), having a combustion chamber domed by 20mm may not help.

I have thought about this, and I agree. I am betting they the F1 guys might be using a little wider valve angles if it wasnt for the tiny combustion chamber they are stuck with. The reason being that the wider the angle means the more domed the piston has to be, and the more domed it is the less ideal it is for the flame travel, distance and the chamber surface area. But its just a hunch of mine. Also notice how they have almost no combustion chamber volume, I am thinking they might be using a recessed piston and make up for the volume in the chamber and therfore the air coming from the squish ends up closer to where it should be.


Mr revhead: I hear what your saying and while I havent made up my mind yet I to some point agree with Bill. I think theres many things that arn't definate but I am pretty sure that the intake port path should always be as straight as possible. But still all these companies dont do it? ben does have a really good point about this though.