Flat-top pistons are flat on top as the name implies. Valve reliefs are
indentations fly-cut or cast into the piston crown so the valve won't hit
the piston crown. If you're planning on running a long-duration, high-lift
cam, valve reliefs would be good as there isn't much clearance between the
inlet valve and piston on a 235. Otherwise you have to grind the seat back
into the head to achieve the desired clearance, which shrouds the valve
opening restricting the flow somewhat and serving to defeat the purpose of
the high-lift cam to a degree.
Did any factory after-market replacement 235 pistons have valve reliefs? I
imagine some speed-equipment pistons did. But these are probably not
available now days.
At 10:23 PM 4/15/02 -0400, James Collins wrote:
>Can anyone explain what the discription "Flat top with no valve
>reliefs" means in reference to pistons. This was from a sale of a
>"Set of 6 Chevy 235 +.030 TRW Powerforged pistons with pins. Flat top
>with no valve reliefs. 3/32, 3/32, 3/16 ring grooves."
>
>
>Shamus
>1950 3100
>oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
Tom Allen
Seattle, WA
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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