Any of you guys out there close enough to the biz of making race engine
parts to know the real pluses and minuses of cast vs billet blocks?
>From an engineering standpoint I'm having trouble understanding why they
don't cast and finish machine this thing rather than machining it complete.
You can get a lot of casting value for the money thrown away turning 300+
pounds of $6.00/pound billet aluminum into $1.00/pound chips for recycling.
And if you can machine it the patterns for casting should be fairly low in
coast; .i.e. maybe just a 2 or 3 multiple of the cost of a finished block.
Maybe the problem is finding the right foundry to do the job. "Lost Foam"
casting process come to mind here. I would have thought that times were
pretty tough in the foundry business and the still surviving aluminum
casting foundries would be pretty hungry for business.
BTW, you can make foundry patterns and core boxes as well as foam pattern
molds the same way they machined the block although patterns still require
lots of hand finishing to get surfaces that will be properly polished and
things like draft angles and shrink allowances will have to be added to the
CAD solid model used to drive the machining software.
Maybe there's some current knowledge in the biz of making aftermarket
aluminum blocks that says the properties of aluminum billet stock in that
size (6061, 7075 or something special?) are better than cast material. To
my simple mind it seems unlikely that you'll get anything like T-6 strength
properties in the center of that big chunk of aluminum.
Maybe the issue is consistency of thermal expansion properties in the area
of the block where the sleeves fit. Problems in this area can result in
sleeves going out of round when the engine heats up resulting in poor
contact and seating of the rings. It can take a lot of fiddling in the
foundry to cure such problems in castings.
Ed Weldon
----- Original Message -----
From: "David in Durango" <adin@frontier.net>
To: "Wester Potter" <wester6935@comcast.net>; "LAND SPEED LIST"
<land-speed@autox.team.net>
Sent: Tuesday, February 08, 2011 6:27 AM
Subject: Re: [Land-speed] Kirkhams are at it again ...
> word is they are trying to machine billet FE blocks.
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