[BYprodriver]

[QUOTE=Gilles;464483]Do you know if this also applies to the later M97.21 3.4 engines? Or they also have the same valve sizes as the 99-2001 engines?
I assume that the increased load on the cylinder walls (w/longer stroke) applies as well, is this correct?

Do you know if the 3.8 engines on the Carrera S also have issues with their cylinder walls due to the longer stroke?

The factory 3.8 engines can have increased cylinder wear, mostly from cold winter startups. I have a 2002 3.6 case with a scored cylinder.

Increasing stroke increases piston speed, which increases loads on the rods. At any RPM if the piston is moving further (longer stroke) it has to move faster to go from TDC to BDC at the same RPM. The longer the stroke, the stronger the rods have to be.

With the later engines you can bolt on bigger valve heads. The early 5-chain engines don't have that option.