4age bigport head: port & polish

[BenR]

jamiemirror Wrote:

BenR Wrote:A good 4age head reqiures ALOT of work to completely reshape the ports, account for casting shift, reconfiguration of the valve seats geometry, valve modification etc.

So a guide would take longer to write than to do the head. Not that i would write a guide on how to do the ultimate 4age head as its what i do for a living lol.

CJ wants good NA head, not ultimate one. As I understand the goal - this must be 150-170hp street engine, not 190-220 hp racing circuit screamer.
Regrinding valve seats and valves, 3-angle job, castings cleaning and porting is not ALOT of work (compared to FIAT 8V DOHC head for example - with more than 3mm wall material removed just to match ports to intake). Toyota have good and precise castings.

Toyota do not have good castings on the 4age lol.

And traditional 3 angle seats do not work, the stock 4age comes with 5 angle seats.

The question is what are general DOs and DON'Ts for bigport 4AGE head.

[jamiemirror]

Quote:stock 4age comes with 5 angle seats.

Are you sure ? Sounds too strange for any production head.

[BenR]

A few production heads run 5 angle, its simply down to the cutter insert they use, adds no real cost.

[jamiemirror]

Just for additional reference.

And some bluetop specs from AE92 site:
http://www.ae92gts.com/ae92gts_engine_specs.html

Quote:Valve seats Refacing angle 30°, 45°, 60°

[Corey]

to BenR

you cuted valve stem guide, you dont worry about your valves?

[BenR]

nope, i dont worry.

It is only cut on the exhuast side, which sticks out a very minimal part in stock trim.

[Corey]

thanks

[Os7213]

Hi BenR I got a question about your porting job..Why do you remove material all around the cylinder bore line around the chambers?:


(For the image can you right click and open it i dont know why the image dont work when using left-click sorry )

Or can you tell me what serve this deck and how much material have been remove from Z axis?

Here my second question, i projected a porting job on my 4age smallport 16v head , and here my idea for the chambers... My idea is to reshape the chambers to the cylinder bore-size for more sqish area do you think this is a good think or it will ruin the head?



Sorry i hope im not too off topic since the question is about porting.

Thank a lot in advance
Ugo

[Os7213]

Up!
If nobody elese know what im talking about dont hesitate please

[jamiemirror]

Your question was directed to BenR first...
IMHO 1st question - these are squish areas. 2nd - I would keep them stock - just polish and round the edges. That way this head will be less prone to detonation with hi-CR pistons. Removing material from squish areas will not ruin the head but will not improve it either. I can't imagine how reshaping the chambers to the cylinder bore-size will give you more sqish area - please explain/draw ?