S38 Oversized Pistons Help

[70deluxe]

Hello.

Mostly lurk on here but think I have a few posts to my name.

I have an M5 that is likely going to need a full rebuild. Will probably need to go up a size or two on the pistons based on the scoring in the cylinder walls that we can see on #4 cylinder.

Couple of questions for whoever might be willing to point me in the right direction.

1. How much could you realistically go up in piston size on an S38 engine?

2. What type of pistons (make) might you all recommend?

3. What is the best source these days for s38 parts? I have used Blunttech a lot in the past for various other projects but wondering if you all might recommend other sources.

Any help and guidance is appreciated.

Thank you.

[alpinass]

I had my engine builder stroke a B35 to 3.7 liter- raised the compression to 11:1 - 84 Stroke. A piston MFG in LA designed the custom forged pistons included rings and pins.

[bbaxter]

I just rebuilt my S50 and went to VAC Motorsports. They were great help and ordered everything I needed. One thing to keep in mind. BMW does everything that needs to be done to that engine before it leaves the factory. The more you do to it, the less street friendly it becomes...

[bbaxter]

If you want my personal thought's on rebuilding a BMW engine you can PM me.