That open block design was used on the Subaru wet sleeve engines back in the 70s and those were prone to head gasket problems.
However, it wasn’t the open block design that was the cause of the problems. It was the removeable cylinder liners sitting on copper rings which was the cause of the head gasket failures; assuming overheating wasn’t an issue.
Is this design being used on the FRS/BRZ?
The FRS/BRZ uses a different engine. The engine is very similar, but since those vehicles are RWD only, the engine was designed with a lower center of gravity. Basically Toyota took the Subaru design and had their engineers modify it for the sports coupe.
Subaru then looked at the chances Toyota made and incorporated some of them into their 4 cylinder engines, particularly in the area of head gasket design. Its a little too soon to tell if it works, I hope it does as I now have a 2014 Legacy with the 4 cylinder engine.
Something tells me that if I were to build a Subaru engine for higher performance…Using either a solid copper or other high quality MLS Head gasket (depending on the induction method chosen)…AND I used top shelf Head Bolts… None of this head gasket nonsense would occur. The regular who stated that he retorqued his cyl head bolts and never saw any head gasket issues seems to suggest to me that the head bolts might be inadequate or of incorrect mettalurgy… Who said they retorqued the heads…was it @ok4450 or @VDCdriver…anyway…it was one of the “guys” here. I forget.
The open deck engine design is in wide use out in the auto world…and no one else has these issues or at least they aren’t a “Known Bug” in those engines. One would think that with such a small cylinder head that warping was not to blame… A straight 6 would face more cyl head warpage risks if you ask me… Who knows…I bet some Subaru performance engine builders know the answer to this conundrum.
Its interesting…I’d like to know some real data on this.
Blackbird