JAKEJR

I've been internet shopping for a set of pistons for the 396 LT1 engine build for my son's car. I've come across pistons made of two different alloy specs - 2618-T61 Forged Aluminum and Forged 4032 High Silicone Aluminum alloy.

I came up blank when I tried finding a site that compared one material with another. Does anyone know the advantages/disadvantages of one Vs the other?

Thanks for the help.

Jake
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96LT1355Z28

iTrader: (2)

Here's a good explination from SRP. 2618 has a higher tensile strength but also has a higher expansion rate. The piston to wall clearance must be made wider to allow for the expansion thus increacing the probabilty of "piston slap" on cold startup. 4032 has a lower tensile stregenth but expands much less so the piston to wall clearance can be closer, lowering the chance of "slap" on cold startup. Plans for the engine like NO2 vs. N/A and street/strip vs. track only will determine what material is best for you.

http://www.who-sells-it.com/cy/je-pi...-fullsize.html

Lonnies Performance

iTrader: (16)

The above is a perfect explanation. For moderate power the SRP type piston in 4032 alloy is a good product for normally aspirated or moderate boost/N20 street applications.

Once you get into the 2618, the added wall clearance will make for more engine noise, more potential oil consumption & less ring life.

Usually for 800 flywheel hp or less the 4032 is OK. Above this, the added strength of 2618 would be a wise choice.