On Sat, 27 Nov 2004, Jerry C Shaw wrote:
> Bentley, page 114, Cylinder Block, Rebore, Item 3., reads: "Maximum rebore
> oversize from standard is +0/020 in. Cylinders that cannot be satisfactorily
> rebored when this limit may be sleeved to restore them to the original size"
>
> Apparently, everyone ignores this, otherwise, no one would sell 0.040"
> oversize piston sets. Just ordered 0.030" oversize pistons.
>
> What's the deal? Any risk here?
The factory was either paranoid or they didn't want to stock oversize
pistons more than +.020.
I can tell you from direct experience that a .040 overbore (max
permissible by exisiting SCCA regs) will work just fine with good pistons.
I run .040 Venolia pistons in the race car.
The key here is (and everyone seems to ignore this) is how out of round
your bores are. If there's a slight ridge or ovality to the bore, then by
all means bore out to the next step. But for whatever reason, everyone
seems to think the right hting to do is to automatically go .030" over
bore. The problem is that when you wear out the bores of the .030" setup,
where can you go?
As another data point, there are folks out there running .060" over bores.
> Thanks
> Jerry
>
> '74 TR6
regards,
rml
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