Time for a change, time for an update. Following on the heels of great past hits, here come the 2010 GRAND SPORT Piston Series. The piston revolution is marching on, with the POLINI piston crowned by a second 1.0 mm piston ring.
The Piston Rings are manufactured of high quality ductile iron with a chromed surface: dependable breakage resistance and improved sealing properties through 2 piston rings with the same rpm ranges and modification possibilities.
Cast and finished in Italy, these pistons show their quality through a high silicon ratio of at least 18%. This ratio is a guarantee for high grade durability and lessens considerably the chance of freeze ups. Compression height is identical with the POLNI piston and the up to date layout rounds out the entire picture successfully. Increased stability is added through the solid inner ribbed structure and the reinforcement on the gudgeon pin eye. The enlarged boost port window is optimized in its position.
Conclusion: the 2010 upgrade of a highly successful product. High quality material, now with 2 stabile narrow piston rings. GRAND SPORT pistons offer the best basis to show what your POLINI can really do.
Aluminum/ Ø: 68.00/ 68.50 mm/ 2x 1.0 mm piston rings
Aluminum pistons, minimum 18% silicon, 42.5 mm compression height same as the POLINI original, inner rib structure and reinforced lip on gudgeon pin eye for improved stability, boost port window square, larger and with optimized position, larger lateral ports with cross web, 2x 1.0 mm piston rings made of ductile iron with chromed surface. Please notice: further important and helpful tips, additional product information, can be found to the right under "article info download". Recommended piston play Irconcast: 12/ 100 - 13/ 100 mm, Aluminium: 8/ 100 - 9/ 100mm Before installation, always control piston play and piston ring stop play and modify if necessary!
SIP TIP: the biconical gudgeon pins also fit, without modification, in a 211cc MALOSSI piston >> saves you ca. 10 g! Lower your cylinder temperature up to 10% by spraying the POLINI cylinder kit with black exhaust paint (see recommendations).