I think the main difference is stiffness - steel is also 2.9 times "stiffer"
than aluminum. An aluminum block would require thicker webs, more gussets,
etc. to control flexing under load, even though the aluminum and steel have
similar strengths. This would be especially true for a racing block like the
FMS one, where maximum stiffness is required.
-Chad
>From: "Larry Hoy" <larryhoy@prodigy.net>
>Reply-To: "Larry Hoy" <larryhoy@prodigy.net>
>To: <mgb-v8@autox.team.net>
>Subject: RE: Ford 302 vs BOP/Rover 215
>Date: Wed, 20 Sep 2000 09:26:28 -0600
>
>I guess I hadn't considered the aluminum and iron blocks would be
>different.
>It's my understanding that 6061 T-6, 7075 T-6 or 356 T-6 aluminum alloys
>have
>essentially the same strength of mild steel, not sure how it compares to
>cast
>iron used in engine blocks. However this discussion has made me run to
>some of
>my reference books, I found that cast iron strengths are all across the
>board,
>some are much less than aluminum and some are much higher. I guess I have
>enough information to be dangerous (and inaccurate) so pick and choose what
>ya
>believe.
>
>Larry Hoy
>
> >-----Original Message-----
> >From: owner-mgb-v8@autox.team.net [mailto:owner-mgb-v8@autox.team.net]On
> >Behalf Of Chad White
>
> >Keep in mind aluminum is not as strong (depending on alloy) or stiff as
> >steel, therefore more aluminum is required to match the strength and
> >stiffness of steel. So, an aluminum block may require more material to
>match
> >the strength of the steel block, hence the disparity between the actual
> >block weights and the material weights.
> >
> >Chad
> >'71 BGT - '94 Cobra 5.0 power in the works!
>
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