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Author
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Topic: hypereutectic pistons
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majik455
Gearhead Posts: 121
From: duluth ga usa
Registered: Jan 2005
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posted 08-05-2005 09:17 AM
   
whats the advantage to hypereutectic pistons ? thanks Ron
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SteveLaRiviere
Administrator Posts: 44921
From: Saco, Maine
Registered: May 99
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posted 08-05-2005 09:22 AM
Less thermal expansion so you can run tighter clearances. The downside is they tend to shatter like glass under even moderate detonation. My own opinion, I only consider them slightly better than stock cast pistons. ------------------
'70 Mustang Mach 1 351C 4V/FMX/3.25 Open
'70 Mustang Convertible 250 I6/3 speed/2.79 Open
'72 Mustang Sprint Hardtop 351C 4V/FMX/4.30 Trac Loc
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
'05 Mercury Sable LS 3.0L DOHC 24V Duratech V6
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n2oMike
Gearhead Posts: 2680
From: Spencer, WV
Registered: Jan 2001
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posted 08-05-2005 09:36 AM
I like them, but they REQUIRE wider ring gaps. If standard rings are used, the rings tend to butt together under heat at the top of the bore and lock into the cylinder. As the rod tries to pull the piston back down, it breaks the top ring land off. 99% of all hypereutectic piston failures have the top land broken off.You've GOT to check and gap the rings with these things. Even standard (non-file fit) rings can be too tight... especially if the engine was bored for the tighter clearances they can handle. When used correctly, they are a great street/strip piston. Their extreme hardness gives them terrific wear characteristics, but with hardness, comes brittleness. They will take a lot, but extreme detonation cam cause them to break. ------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220
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blackford
Journeyman Posts: 45
From: Corona, Ca
Registered: Jan 2004
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posted 08-05-2005 12:28 PM
Tighter bore clearances...a nice advantage for a short skirt stroker piston to reduce piston rock.Good wear characteristics They don't absorb as much heat as other piston types. Instead, they tend to reflect more heat back into the chamber enhancing power. Since they don't absorb heat as much, the upper ring gets hot and thus the wider gap is needed to account for thermal expansion. ------------------
Tracy Blackford
'65 "Black" ford FB, 331 with H beam 289 rods, KB322s, fully prepped 351w heads, 282S cam, C-4 auto, 3.50 9" posi. Many Suspension and handling mods. 4.5 year restomod project completed in May '04. 313 RWHP @ 6300.
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Tom G
Gearhead Posts: 723
From: Bethlehem, Pa USA
Registered: Nov 2001
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posted 08-06-2005 09:22 PM
quote:
Originally posted by blackford:
Tighter bore clearances...a nice advantage for a short skirt stroker piston to reduce piston rock.Good wear characteristics They don't absorb as much heat as other piston types. Instead, they tend to reflect more heat back into the chamber enhancing power. Since they don't absorb heat as much, the upper ring gets hot and thus the wider gap is needed to account for thermal expansion.
Great Info! I didn't know about the ring problemm possibilities.------------------
67 Mustang F/B 302 GT-40X FMS engine RPM Air Gap 650 Holley DP Crane 1.7 roller rockers, Edelbrock Performer Nitrous system, Dynomax ceramic coated headers T5, cable clutch Flows X Pipe 3.89 9". Clearwater Aqua GT Clone Vintage wheel works 40 series 16X8 225 front 255/50 rear drag radials 308 hp at the rear motor only 13.25 @103mph
92 VERT triple black 5 speed, 88 GT 5 spd 77k original miles Red and Silver
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