Toyota 16v 4age red-top cylinder head query

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Toyota 16v 4age red-top cylinder head query

Postby Os7213 » Sun Nov 12, 2006 9:25 am

Hi Mr. Croft

My name is Ugo. I¢ž¢m now in the complete building of my new Toyota 16v engine for my Ae86 1987.

Here the setup for now:

-4agze head (ex small port 16v supercharged model)
-Black top block (connecting rods+crank)
-20v type individual throttle bodies (itb)
-Toda camshaft 272˚ 9mm lift
-Toda spring
-Toda pistons 81mm bore 20mm pin 77mm stoke using 4age20v Con-rod+crank.
-Toda under-bucket shims
-Toda Cam-gears
-MegaSquirt unit

Few items missing but I¢ž¢ve not finish the setup yet.

I¢ž¢m now trying to do my own porting on the head. (That my first 4age building but I really want to do it by myself!)

Here my question, I¢ž¢m now at the combustion chambers and wanted to create squish area on the head from the chambers to the cylinder bore.
Can you give me some tips about how measure the perfect depth of the squish area? I¢ž¢m trying to find the perfect height of the piston at is top-dead center Vs the head to have my squish area depth.
Since I don¢ž¢t have choose the thick of my new head gasket (I think I will go for 0.5mm-0.6mm since I want more compression) I know I can¢ž¢t measure the depth of the squish area but I want to make some math tests before buying the gasket to optimise the squish effect...think I¢ž¢m right?

Thank a lot in advance
Ugo
Last edited by Os7213 on Sun Nov 12, 2006 10:31 am, edited 2 times in total.
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Postby Guy Croft » Sun Nov 12, 2006 9:37 am

Sorry,

I'm lost with all those coded parts, never heard of half of it - please advise me as to what it all is! Not even sure I know what make the engine is.

GC
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Postby Os7213 » Sun Nov 12, 2006 10:31 am

I¢ž¢m sorry!
I think you call the motor Toyota 1600 this motor = 4age. All 4age-4agze are 4cylinders, twin cams and 4age are 1600cc

Here is some info hope that will help you to identify the motor!
All the Toyota 4age motors comes from Toyota Corolla from 1983-1995.But 91-95 only in Japan
Here the different types:
4age Red-top 16valves with small-ports
4age Blue-top 16valves with big-port
4age Silver-top 20valves using AFM (Air flow meter sensor to run) Individual's throttle bodies (itb) for intake
4age Black-top 20valves using MAP(Manifold air pressure sensor to run) and Individual's throttle bodies (itb) for intake.

Also you have the supercharged version of the 4age called 4agze used in Toyota Mr2 1987-1991 these motors are classed by Generation:
1st Gen 4agze: 16valves,supercharged, big port
2nd Gen 4agze: 16valves, supercharged, small port, with external oil drain
3rd Gen 4agze: 16valves, supercharged, small port with external oil drain


All the heads and blocks are the same, have same piston size, same connecting rods, chambers etc., the only difference between them is the port size, induction, sensors to run, or stronger internals - so you can more or less match-up any head with any block.

The 4agze is the Toyota motor used in MR2 supercharged. I¢ž¢ve only taken the head that is the same small port as the 4age 16valves red-top head used in Toyota Corolla GTS, Ae86 Toyota Trueno. The small port is the best choice for me since I want to port the head and change the porting configuration I have more material to play instead of the big-port head.

I¢ž¢m matching the head with a black-top block used in Ae111 20valves Toyota Corolla - the same as a 4age blue-top or red-top block with stronger internals and the stock Ae111 motor running with itb.
I¢ž¢m using itb¢ž¢s to ensure high rpm range and very good throttle response instead of the stock intake manifold from the 4age

I¢ž¢m changing piston to fit the 16valve head.
The stock 4agze head also run with lifters these one have outer-shims on top of them and with high camshaft duration these shims can "pop" out of the lifters and damage the head that why I¢ž¢m using under lifters shims.
The Megasquirt is a fully programmable management ECU.

4age 16valves heads are used in Toyota Atlantic series and N2 race.

Just to be sure do you know what I mean by squish areas?

Hope I have explain the 4age-4agze engines well and If you have other questions don¢ž¢t hesitate!

Thank you
Ugo
Os7213
 
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Location: Quebec

Postby Rich Ellingham » Sun Nov 12, 2006 6:31 pm

Okay, I know nothing about these engine, but to help this post I offer some picutures, please inform Ugo if these are wrong for you unit. Guy may have some general things to say about squish, and its relevance.

4age Head std
http://www.billzilla.org/4agheadpic.jpg
4age bottom end disassembled
http://www.billzilla.org/4agblock.jpg
Head cross section
http://www.billzilla.org/16vhead.jpg
port view
http://www.billzilla.org/4agbigport.jpg
This information come from, http://www.billzilla.org/4agstock.htm ,

rich
book 38
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Postby Os7213 » Sun Nov 12, 2006 11:17 pm

Thank a lot Rich this is the right engine! ;)
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Postby Guy Croft » Tue Nov 14, 2006 9:25 am

Ok, now I have a handle on this, well done for putting the details together so constructively, and Richard, thanks for the photos. There is some commonality between the combustion chamber here and one I did last year (see photo below).

Here's your question:

I¢ž¢m now at the combustion chambers and wanted to create squish area on the head from the chambers to the cylinder bore. Can you give me some tips about how measure the perfect depth of the squish area? I¢ž¢m trying to find the perfect height of the piston at is top-dead center Vs the head to have my squish area depth. Since I don¢ž¢t have choose the thick of my new head gasket (I think I will go for 0.5mm-0.6mm since I want more compression) I know I can¢ž¢t measure the depth of the squish area but I want to make some math tests before buying the gasket to optimise the squish effect...think I¢ž¢m right?


My simple answer may disappoint you but nonetheless here it is:

There is no way to determine the optimum squish (proximity of piston crown area to corresponding cylinder head area). This can only be done a) by trial and error, examining the specific fuel consumption and knock-resistance with various trial layouts - ie: varying the area and proximity (closeness) of the opposing regions, or
b) by computer analysis.

The reason for the complexity lies in the way a squish region works. What squish does is generate little vortices that form as the piston closes on the head face; these fly out into the fuel-air mixture and turbulate it to produce good mixing. That's it in laymans terms, and of course, like with everything to do with engines - clever people in the automotive industry have developed terrifying mathematics and expensive software to simulate it.

What you need to know is that as a competition engine and a 16v one as well you don't need to worry about the squish to the extent that you need to change 'what you've already got', it will be fine as designed by Toyota. So my approach would be to run the pistons flush with the block and put your talents into areas where you can definitely generate an improvement - porting, seat work eg.

Of course you can increase the amount of squish by running the piston as close to the head face as possible, but who knows whether it will give more power? It may give less - after all - it takes energy to create squish - that energy has to come from somewhere. More is not alway better.
And of course we have to remember that the pistons must not hit the head (or gasket) and that the valve reliefs must safely accomodate the cam lift around TDC inlet and exhaust.

These latter aspects are real practical issues. I'd never run a piston closer than say, 40thou" to the head. This gives plenty of room for rod stretch, thermal expansion, and if the engine runs a bearing - the piston won't smash the head to pieces - if you catch it in the early stages anyhow..

GC
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Postby SteveNZ » Tue Nov 14, 2006 11:17 am

A slightly off topic question. There is a rumor that the 4AGE design is based on the Ford BDA. Is there any truth to this?
SteveNZ
 

Postby Guy Croft » Tue Nov 14, 2006 11:47 am

I don't there is much in common although the BDA might have inspired the design in the first place, but that was true of many 16v units. As far as the key parameter is concerned (given that they both have er, 'typical' 16v combustion chambers) ie: port layout and design, not commonality at all. The BDA is classic downdraft port. Not quite F1 standard, but still so superbly effective.
This Toyota unit belongs to the new generation of port type - sidedrafted and cavernous entry region - then into very short splitter region and almost right-angle turn to valves. Must confess I do not know the design philosophy behind such a big port entry region, when I first saw one I thought, that's big, will the air velocity be low? But - no doubt it does work. I know of people in the USA getting over 400bhp from 2 liter Honda units (same idea) normally aspirated.

If anyone who's reading this works in cylinder head design in the auto industry I'd like to know more about the thinking behind this new style of port.

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Postby Os7213 » Thu Nov 16, 2006 3:03 am

Hi guys. For you answer SteveNz The Toyota 16v head is a close copy of the Ford 1600c BDA head!

For the ports configuration Toyota have completly change it from the 4age 16v to the 4age 20v. When the 20v head configuration has been done the enginner have made the intlet ports more higher than the 16v.
With only a smooth curve in it not a "90deg" type curve to the seat. The exhaust port is practictly the same for the 16v and 20v. But the intlet ports have totally diff’‚©rents shapes... And Honda too since many year are greats fans of the "90deg" curve at the valve seat...You have two majors debate the first one: An aggresive but short inlet port so the air take a little way to goes in it or the smooth and long one who give less restriction but the air take more time traveling in it!
But finally i think they found the 16v ports types are better then the 20v since the 16v is usually used for most application(Atlantic formula,N2 ect...)

I think the desing of the 4age head with Big entry serve unacceptable nothing to a certain point like a stock head but for a racing application when you change valve\seat size the big ports begin to work at full potential.
The 2 heads(16v blue-top(big ports)-16v Red-top(small ports)) as been none for there propreties. The bigport provide high rpm,and the small one provide more torque and all this with the same valve size! So from there we already know than the ports size vs valves size are not used at their full potential. The N2 specs for 16v motors tell to ports the inlet ports to 67mm! with always the same valve diameters...I think theses specs are old and non accurate but i think Toyota what a particular desing in the ports...A cone form...from the entry to the valve seat the ports after porting look like a cone form with big entry and a small valve! SO the air have maximum place and the small valve have more suction power so its a perfect combinason.This is only an idea not a affirmation but the desing look like this.

Hope i have help a little
Ugo

Oh and btw sorry for my poor english skill ;(
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Postby Guy Croft » Thu Nov 16, 2006 10:51 am

No, and before this thread runs completely wild, there is little in common between the BDA and the Toyota 4age other than bore, stroke and valve sizes. That the 4age was a 'mass produced BDA' is a rumour (read: assertion) that may cheer some and not others (BDA owners eg) and no more than that.

I quote from club4ag.com:

"Contrary to a false assumption that the 4A-G is a copy of the Cosworth BDA, (coincidental ‹Å“A¢ž¢ series designation on both engines). There are little, if any, interchangeable parts between the two engines, outside of maybe some nuts and bolts... The Cosworth 4-valve design started life using the Ford Cortina engine block, with its distributor located on the side of the block and progressed to belt driven Escort engines. The basic block was, like the current formula Atlantic engine, based on a production block. Most of the Ford blocks that Cosworth used could be taken up to 2 liters. The 4A-G is limited to around 1.6 liters maximum, because of the deck height and bore spacing. The included valve angles for the BDA is 40‚°, along with what has become a Ken Duckworth design feature, and that is the use of a separate camshaft tray. To the contrary, the 4A-G has a one-piece head with the camshaft saddles cast right in. The included valve for the 4A-G is 50‚°, more similar to the earlier Alfas or other Italian designs of the 70¢ž¢s"

The BDA head has downdrafted ports, different coolant galleries. It is important to distinguish between designed-for-purpose competition engines and production units, however good they may be. The BDA head and the full-spec BD series derivatives are pared-to-the-limit technical works of art and thoroughbred race engines and always will be.


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Postby Os7213 » Thu Nov 16, 2006 3:43 pm

Thanks a lot for the infos about the BDA vs 4age head!

Almost forgot, about squish area I will play with the piston height from 0.032in to 0.040in to the head.
Since I will use the Ae111 black-top connecting rods who are stronger than the stock 4age 16v connectings rods I think and hope the rod stretch will be reduce to the maximum. Since I will use a 0.5mm head gasket for more compression ratio I hope the new squish area machined in the head will give the same result and even better than the stock squish area.

For the valve clearance the Toda pistons offer additional space between valve and top of the piston so I can raise the maximum clearance a little.

I will also make tests since I have 2 heads (1 blue-top, 1 red-top), I will prepare the 2 head, port them to match the gaskets size and clear the entry to the valve, and since the combustion chambers on the blue-top head are damaged on the exterior I will machine new squish area on it and solve the problem!

The 2 heads will have the same cams setup so I will be able to choose the one better for my application. I project to use the blue-top head for drift race and the red-top head for circuit race. If you are interest I will put pics of my work my first work will be on the blue-top head.
I will also keep stock valve seat on the 2 heads, do a 3 angle valve seat job on each head but I will not change valves +seat length,diameter or configuration so we will be able to see how a port on 4age head can be useful with stock components!

Thank a lot for all the infos and reply
Ugo
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Postby Os7213 » Sat Nov 18, 2006 7:25 am

Hi everyone!

My porting job is begin so i post somes pics from in and there during the work:

Image

Image

Image

Image

Today the port job on one of the intake port is almost done but I need advises for the finish.. Someone told me to use a 400 grade sandpaper but im affraid of a too shinny finsh if i do it with a 400... If someone have tip dont hesitate ;)

Oh since its my first porting job be smart guys! But i think the final result will be good, Ill post more pics when the first port will be completed.

Thank
Ugo
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