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      09-26-2013, 03:55 PM   #59
Boss330
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Quote:
Originally Posted by swamp2 View Post
The characteristics of an engine can certainly be altered by over and under square designs but the differences between them are dwarfed by the effect of turbo charging.

Using a caliper and paper print out of the new block (ugh, I am really that bad... although I could have also gone the Photoshop route) I calculate an 8.0 mm cylinder wall thickness for the S55 meaning the bore spacing is 97.6 mm. If they wanted an even mm bore spacing I'd then guess 98 mm. This makes the new block a full 33 mm (1.3 inches) longer from 1st to last bore.

Either way, I was already firmly convinced that a 1.4 mm cylinder wall spacing was completely unfeasible from a structural and thermal fatigue point of view. I posted that there was a new bore spacing at least a day or two ago here buried in one of the long discussions...

It is a new block and thus new head as well. It is based highly on the design of the N55 block but indeed has a different bore spacing.
See my previous post re bore spacing. http://f80.bimmerpost.com/forums/sho...3&postcount=52

Where do we have the 91mm bore spacing info from?
Is it a verified measurement or just what everyone believes?
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