Pistons and Rings

Stock replacement pistons are no longer available from WOT-Tech.  The following is left for information purposes only.

Stock replacement hypereutectic pistons now feature a skirt coating, to reduce friction and heat.  GM upgraded the #5 and #6 cylinders with skirt coated pistons on the 3400 minivans,  but no 3100s ever had the coated skirts, which should eliminate or at least reduce the piston slap noise common to a cold start.

The 3.1 Iron head pistons are listed as a high compression replacement, which will drop right in using the matching ring set.  These 12cc dished pistons put a 3100 at 10.72:1 compression when using stock 3100 heads and head gaskets.  When using the iron head 3.1 head gaskets, this compression ratio goes up to 11.39:1.  This information is taken from the 60DegreeV6.com compression ratio calculator.  The 3.1 iron head pistons do not come out of the bore in the block, which increases the quench.  For a better explanation of quench and pistons, please read this article (written about the 3400 and 3.4 iron head pistons but the same theory applies.)

Image	Name	Price
	Forged 3100 Pistons Diamond forged pistons are known for their quality in the racing world, and now they are available for the 60V6 engines.  These skirt coated, full floating forged pistons are made from 2618 alloy, for less thermal expansion compared to traditional forgings.  Traditional forgings need …	$574.99