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TurboKraft TurboKraft is offline
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Join Date: Mar 2005
Location: Phoenix, AZ
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Having done this, I'd suggest you don't machine them and instead buy new pistons.

After 9.0:1 CR it gets pretty thin. And thermal coating the crown only helps so much.

It's thickest above the pin bosses, 90deg from the valve reliefs. You can take out a lot of material there. But note how the inside of the piston is pocketed under the valve reliefs -- not a lot of material there to take away, and leaving it leaves a really poor shape for a piston crown. Not combustion-friendly. If you try to machine a really low dome on them, like Turbo 3.6 but 8:1, don't expect them to last long term.

I've got several sets of take-out pistons from client engines built at other tuner shops, plus some of my own early engine experiments. Not pretty. All motors ended up getting replacement pistons or pistons & cylinders.

Just my $0.02 having been there, done that.
Chris Carroll
TurboKraft, Inc.
Tel. 480.969.0911
email: -
Old 03-25-2010, 12:33 PM
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