Smallport 4AGE Head Cross Section Drawings

[idealneil]

Hi all, I am after, if anyone has some or can recall where they saw some, cross sectional drawings of a smallport 4age head.

Looking into head porting and sizes of ports and angles etc and just trying to get an idea with out having to cut up a head to work it all out.

Any ideas or links would be appreciated.

Even a bigport cross section would be helpful as well.

Cheers Neil
Timaru

[Lloyd]

Pictures helpful or wanting full technical stuff?

www.billzilla.org/4agstock.htm
http://www.billzilla.org/engcombust.htm

[RedMist]

What he wants is a cross sectional so he can figure out how far to push the ports without punching into a water jacket/spring platform/ etc.
The Billzilla photo will give you a start but I gather you're looking at about 10 mm or so cuts throughout the entire head?
If so I certainly can't help, we did nothing but reduce the port size on all our 16 valve 4age's. Unless you are throwing a tonne of puff into the port I think you're heading the wrong way.... and if you are then I think you have the wrong head.

[idealneil]

Hey, no not heading for PUFF as you say ie turbo.
Looking for N/A. Thinking more of heading in the direction of trying to stand the inlet port up more, to get them more direct into the valve. And then having to fill in the bottom of the inlet tract.

Initial thinking at this stage. Just got acouple of books that Im reading through and working through. And have picked the smallport head to work with.

Did you detail or record any of your experimental sizes / shapes RedMist?

Cheers Neil

[QikStarlie]

wide valve angle is not going to make it easy. i chopped the front of a port off flush with the head. one day when i was bored. you'l run into the valve spring area before getting a straight shot like the 20v head. maybe able to raise it to some point and get a longer short turn radius i guess.

[RedMist]

Bigport head dramatically reduced in size. Engine pulled 178whp with a north south transaxle on a dynojet. (but I suspect mid 180's was possible with more exhaust work). Port offset was because the head was originally mated to carbs. And yes I know it's a bladed port divider. Weird but we never had success on the flow bench with an aero divider. Bladed always increased flow.

You can see we have raised the port roof a little, but it's not much in terms of creating a downflow port. The 20 valve is considerably better in this regard, but the bloody manifold is a mess. The manifold to head face is like they originally intended the ITB's to sit considerably higher then found it wouldn't fit under the bonnet so just milled off the manifold face (and then recast the mounts). It's got an ugly sharp angle at the face and flow tumbles disgustingly into the port.
As an aside have you checked valve area? This is where the B16 blows the 4age out of the water.


16 valve 20 valve B16

IN 5467.94 6618.55 6842.39
EX 4085.64 4247.43 4926.02

Then there is my secret 1600cc weapon... I'll have a play with one day... stock valve sizes.
IN 7926.24
EX 5890.49

[Flannelman]

If I were you...

Raise the port roof, starting at the face and working back to the valve stem.
Fill the floor so it has the same angle as the roof.
Smooth out any stock casting stuff ups.
Increase port volume slightly.

Exhaust is the same.

Downside is custom manifolds will be needed with the same port angles so there is no disruption to flow.