Rishi
Still waiting on some shims!
Its to do with the various metals used 2618 and 4032 and the different ways in which these work and react in different applications and how this in turn affects your clearance, niose, performance and wear...
4032 - is a low silicon piston. These are more for street applications. Low silicon pistons expand less and so can run tight clearances as with the likes of HKS. However the 4032 piston can become brittle under extreme stress and crack. If the 4032 starts to crack it continues and causes mass failiure.
2618 - is a zero silicon piston. There are more for higher power/pressure applications. Zero silicon pistons expand more and so require greater piston to wall clearance like the JE and CP for example. This can make them a little more noisy on cold start up. However they will handle greater pressures. In the unlikely case where a 2618 piston were to develop a crack it would lead to a lower point of stress and stop. The piston would still work fine..
Rishi
4032 - is a low silicon piston. These are more for street applications. Low silicon pistons expand less and so can run tight clearances as with the likes of HKS. However the 4032 piston can become brittle under extreme stress and crack. If the 4032 starts to crack it continues and causes mass failiure.
2618 - is a zero silicon piston. There are more for higher power/pressure applications. Zero silicon pistons expand more and so require greater piston to wall clearance like the JE and CP for example. This can make them a little more noisy on cold start up. However they will handle greater pressures. In the unlikely case where a 2618 piston were to develop a crack it would lead to a lower point of stress and stop. The piston would still work fine..
Rishi