what forged pistons brand

[filh]

everything but camshafts is stock .
Never got overheating , even in hot weather conditions .
Stock radiator is use,
Crank and rods are non balanced .
These oem parts are very well balanced in factory .
Phil

[oldeskewltoy]

WARNING:

All the piston manufacturers have the WRONG information when it comes to the volume of a 4AGE head....

A uncut stock 4AGE head has 36.25-36.50 cc combustion chambers. There IS NOT an untouched production 16V 4AGE head ANYWHERE that has a combustion chamber anywhere near 39CC!!!


Below is a head I recently ported. The upper view is the haed with stock chambers- 36.25cc. The lower head is the same head AFTER I opened up the combustion chambers too 39cc. If you have a tough time seeing the difference, look at the space between the chambers




My point here.... 39cc chambers are no where near stock. That means the Probe Industries claim of 9.21 CR is dead wrong!


Now on a completely different note, the Probe Industries pistons DO look like they will run nicely in a stock, or mildly modified engine. GUESSing here, but the actual CR is likely going to be in the low to middle 10 to 1 range with those pistons under a stock 36.25cc chamber head.



30cc chambers are tiny.... have they been "opened" up yet? See above photo. What porting have you done to improve the flow. A quality porting job can ad power, AND lower temps @ the same time.

Concerning the piston lands...I'm not sure which pistons you are using, but TRD had offered DIFFERENT pistons for rally, as opposed to N2 or other track type events.

For rally you want a full skirted piston, have the piston skirts coated with a low friction coating. Also have the piston domes ceramic coated to dispel the heat.

[filh]

I bought the car with the engine in .Can't say how it was ported , but I'm sure to have 30cc chamber, not opened .
The job made in the chamber is very clear , but what's the interests in increasing the volume ?

I had oem Toyota pistons in the engine and made repair with Mahle pistons , and another Japanese brand (can't remember the name , but typicaly japan name).
Impossible to get now , and TRD are out of stock too .Both used engine I bought had stock Toyota and pistons were broken between ringlands.
I don't have heating problems , and broken pistons have no sight of overheating , on top or side .

phil

[oldeskewltoy]

filh Wrote:I bought the car with the engine in .Can't say how it was ported , but I'm sure to have 30cc chamber, not opened .
The job made in the chamber is very clear , but what's the interests in increasing the volume ?

With each cut of the head you raised the engines compression - 36cc offers one volume, 30cc is nearly 20% smaller. Smaller chamber = more compression

filh Wrote:I had oem Toyota pistons in the engine and made repair with Mahle pistons , and another Japanese brand (can't remember the name , but typicaly japan name).
Impossible to get now , and TRD are out of stock too .Both used engine I bought had stock Toyota and pistons were broken between ringlands.
I don't have heating problems , and broken pistons have no sight of overheating , on top or side .
phil

I apologize for being unclear. When I mentioned TRD, I was using it as an example of two different, and yet similar pistons.

My recommendation for a piston would depending on what you intend to do with the current head.
1) IF you choose to keep the current head, I'd look at the possibility of using a late OEM 4AGZE piston(8.9 to 1 under a 36.25cc head) under your 30cc head, the compression of the 8.9 to 1 piston will be close to 9.8-10.0.
2) IF you choose a different head(more chamber volume), then the pistonsI'd be looking for would have a volume of about 3-5cc (similar to piston above), BUT will a FULL skirt. Once I found the pistons, I'd have the skirts coated with a friction reducer, and the piston tops coated with a ceramic coating to lower piston temps

[filh]

I 've decided to put a stock head ,and read that ae86 TRD GRA uses 2 chamber sizes :
The rally one : 36,5cc with 10.8 CR
The "race" one : 33.00cc with 11.8 CR.
Got the trd reference for pistons , but as they're unavailable .......

I guess stock chamber are 37cc or 39cc.
I saw on Wiseco or Wossner site that some have coated skirt , but don't know about piston head .

My machinist must have them ordered and all measurments will be done .
I was not searching for more power (got 140cv on dyno) but just reliability.
And with an increased CR , I'll have to fit bigger injectors .
Future will tell.......
Thanks
Phil

[robokill]

Filh, if you wreck so many engines why not make one good one.

modify the head to Oldskew specs (trust me I have seen the results its really good)

I would not use Wiseco pistons because the dome is way to steep. Rather take Toda (the top of the dome is flat and better finish)

Don't stare yourself blind on compression. IF you enlarge the chamber the Toda will do fine.

But lets look the other way around. What kind of engine do you want?

Power? torque? Revs? reliability?

And then, how much is it allowed to cost? Just randomly building something itsn't that good. I know a guy in NL near the belgium border who is really good with 4age's. If you want I might be able to get you in contact with him.

[filh]

First I must thank you all for your interest .
As I already said , I don't search a big big engine .
I had 140hp on my machinist Dyno and I found it enough for my old heart....
The machinist did engines for the Fina ae86 competing in European Tourism Championship , some years ago .
It was Gr A time and he worked of course with TRD ;
But , as these times are gone , you now have to work with other brand .
Machinist told me that ; when building 5 engines , I'have to mill pistons heads to adjust the CR (of course the head is milled too).

To Oldeskewtoy : One thing is not clear in my mind : if you open the combustion chambers , you increase the chambers volume ? So the CR decrease ?
On the other end , when you reduce the flat part of chamber , you loose the refocusing of gas mix in the chamber center ?
Don't understand very well that ? Maybe the language understanding , as english is not my mother tongue (far from that...only a little belgian )
To OLdeskewtoy again : as I'm starting with a stock(used) head ,do you do a lot of work in ports : increasing? cutting angles, polishing .
Maybe some pics (like your excellent one above in this post )
Email if you prefer : [email protected]

Regards .
PHIL

[totta Crolla]

Phil, honestly I think a smallport is the way forward. I was having exactly the same issues as you, and yes I may have to eat my words but so far the smallport seems a better rally engine. Better torque band and you don't need to rev them so high. They will of course go to the limiter, like a bigport but not as eager but they perform better in the mid range.
I'm going to do some more 30-60mph times as a comparison.
To avoid the wiring issues I run mine on the bigport ecu with all of the bigport sensors and injectors so the performance is probably a bit off of a proper smallport setup.

[filh]

Thanks for that info Totta Crolla .

But here in Belgium , smallports are rare to find .I bought a 7 seven ribs block some time ago and much to my surprise , all internals were just like a 3ribs bigport .
But of course I know a real smallport is stronger as internals are a little bigger and heavier.
But I can't explain why pistons are so weak in bigport. That's why I'll buy forged ones.
In my mind , it's impossibke to buy a stock smallport and fix it in my rallycar.
It must be opened for rebuilding Most of these engines are 20 years old and are sport engines.
Im just busy with a bigport head , cutting some angles in ports and having some polishing inside .
Phil

[oldeskewltoy]

filh Wrote:To Oldeskewtoy : One thing is not clear in my mind : if you open the combustion chambers , you increase the chambers volume ? So the CR decrease ?
On the other end , when you reduce the flat part of chamber , you loose the refocusing of gas mix in the chamber center ?

filh - the chambers were enlarged for the purpose of lowering the CR, to run the pistons below



My client had TRD Atlantic parts (similar to what I'm selling - http://www.aeu86.org/viewtopic/trd-rods-...ns/t/10880 ) and he is using them with stock AFM AE86 management, and so he needed to lower the CR to a point that it would run on the stock ECU


Here is the build story on it - http://www.hachiroku.net/forums/showthread.php?t=23131




Here is a more detailed view of the old, and new chambers. You will note the "flat part of chamber" has changed, but only enough to add a tapered edge that will minimize the chance of pre-ignition(ping). The part of the chamber I opened up were on the sides on the pistons where there is no "squish area" = "flat part of chamber"

filh Wrote:To OLdeskewtoy again : as I'm starting with a stock(used) head ,do you do a lot of work in ports : increasing? cutting angles, polishing .
Maybe some pics (like your excellent one above in this post )
Email if you prefer : [email protected]

Regards .
PHIL

http://www.aeu86.org/viewtopic/ost-porti...ts/t/10896

Some photos of my work - http://s79.photobucket.com/albums/j143/o...ltoy/MOmo/


You may email me if you would like to discuss my services [email protected]