What pistons are people using?
07-19-2007, 02:36 PM
#21
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Diamond: Great pistons for 25Kmi+ until a fixed boost leak over-boosted it.
Mahle: Brittle alloy, weak ringlands. Destroyed ringlands with some detonation, TSP motor lasted 35miles. A lack of expertise and knowledge by the vendor for suggesting 'thermal coated' (graphite) 4032 silicon alloy pistons for a 17psi motor.
I talked to JE, JE believes a larger top ring down space is important for strength with FI (valve relief results in a thin weak spot). They recommended against thermal coating because it flakes off in high-hp applications (ceramic coating doesn't expand/contract same as aluminum).
Wiseco has a beefy heavier cheaper piston due to forged side reliefs (not milled like others). I believe their top ring down space is larger also, at least their compression height seems taller than other brands. I'm building a 4.125 x 3.622 forged motor next, and although I do like Diamond pistons, for the size I need only Wiseco has off the shelf pistons available.
Mahle: Brittle alloy, weak ringlands. Destroyed ringlands with some detonation, TSP motor lasted 35miles. A lack of expertise and knowledge by the vendor for suggesting 'thermal coated' (graphite) 4032 silicon alloy pistons for a 17psi motor.
I talked to JE, JE believes a larger top ring down space is important for strength with FI (valve relief results in a thin weak spot). They recommended against thermal coating because it flakes off in high-hp applications (ceramic coating doesn't expand/contract same as aluminum).
Wiseco has a beefy heavier cheaper piston due to forged side reliefs (not milled like others). I believe their top ring down space is larger also, at least their compression height seems taller than other brands. I'm building a 4.125 x 3.622 forged motor next, and although I do like Diamond pistons, for the size I need only Wiseco has off the shelf pistons available.
07-19-2007, 03:01 PM
#22
Hmmm I have Mahles and they seem to be doing fine so far from what I can tell. For those of you who have had bad luck with them, which size did you get? I have the -4cc version, could I potentially have the same problem as the -12/-16/-32cc dished ones? Or is the bigger dish what causes the problem?
07-19-2007, 04:41 PM
#26
Originally Posted by cablebandit
not anymore...broke the ringlands twice with no detonation (approx 800rwhp...12deg timing 11.0a/f and c-16)...the area is THIN where the top land meets the piston. My wisecos next to it are like an anvil next to aluminum foil. these were 402 stroker/boost pistons. A Sponsor has had the same issue as well but i will let them tell their tale if they want
cable i thought u said u didnt have weisecos or hoped u didnt when we were talking in the other thread?
07-20-2007, 08:26 PM
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Originally Posted by slowbrakiller
what is the thermal coating for?
Mercedes experimented with carbon pistons and it improved power and emissions. (pdf)
