what forged pistons brand

[filh]

Thanks for your interest.
To resume : As I said above , the engine was correctly tuned (timing and injection) and was verified on dyno bench.
This last engine was use in about 1500km of rallye stages .

My machinist mostly work on race engines .
He was the engine builder when Toyota competed in European touring car championship, with the AE86 Fina (Fermine / De liedekerke)
He has a lot of experience and make many engines like Citroen C2R2, winning cars in local rallye here in Belgium.

My head was too much shaved , due to multiple milling (in fact each time the engine broke )head chamber are now 30cc. I think stock head is 37cc.
The headgasket is 1,7mm thick (oem Toyota late 4AGE engine)

The C.R. is 10.6.
Each time the engine was rebuilt , I used new pistons : Mahle , and another Japan brand .
And it was always the same result: broken rings and ringlands

I bought two stock used engines . Opened them and found same spectacle as in mine : broken rings and ringland .
That's why I don't want to buy another used engine , even smallport.

I've decided to change the head , starting from a stock one .
And i'll order Wiseco or Wossner forged Pistons , giving 11.6 CR .
But as the engine is near from stock (only 2 small Catcams and a light flywheel)I'll need more petrol and will have to install bigger injectors and AFR.
Hope it will be more reliable .......
Thanks again .
Phil