250r back to life!
#66
03-02-2002, 09:17 PM
#69
03-05-2002, 11:58 AM
Guys,
Here's how it is.
Forged Piston = greater coefficient of thermal expansion than cast, period. The heat is held in the piston because it is more dense than cast.
Cast Piston = higher content of silicon for greater strength and wear resistance. The heat is transfered faster from piston to cylinder because of the silicon.
Depending on what alloy the cylinders are cast from and what heat treat was performed and how well, and whether the cylinder is alloy-chrome, nikasil, electrofused or sleeved, your going to have different expansion/contraction rates peroid. Not to mention rings and thier properties...
I used a Wiseco in my YZ250 for years, but I love cast pistons.
I have an ART(ProX) in my Honda
I have a forged in my 426
I have a forged in my 520exc
I have a forged in my 660
I have a cast in my 250r
Do ya see a pattern?
This subject can be argued for centuries. to each his own. I've seen peoples install/break in procedures that would make you laugh at how wrong they have been doing it.
I say, Follow the manufactures suggested instalation instructions unless your having a builder do it. Your builder should know his stuff through his experience. Any and all high performace engines have flaws and will fail sooner or later, from Top fuel to offshore hydro.
my .03 1/2 cents
regards,
theNUT
Here's how it is.
Forged Piston = greater coefficient of thermal expansion than cast, period. The heat is held in the piston because it is more dense than cast.
Cast Piston = higher content of silicon for greater strength and wear resistance. The heat is transfered faster from piston to cylinder because of the silicon.
Depending on what alloy the cylinders are cast from and what heat treat was performed and how well, and whether the cylinder is alloy-chrome, nikasil, electrofused or sleeved, your going to have different expansion/contraction rates peroid. Not to mention rings and thier properties...
I used a Wiseco in my YZ250 for years, but I love cast pistons.
I have an ART(ProX) in my Honda
I have a forged in my 426
I have a forged in my 520exc
I have a forged in my 660
I have a cast in my 250r
Do ya see a pattern?
This subject can be argued for centuries. to each his own. I've seen peoples install/break in procedures that would make you laugh at how wrong they have been doing it.
I say, Follow the manufactures suggested instalation instructions unless your having a builder do it. Your builder should know his stuff through his experience. Any and all high performace engines have flaws and will fail sooner or later, from Top fuel to offshore hydro.
my .03 1/2 cents
regards,
theNUT