Most JE shelf pistons include double spiro locks as standard equipment. These locks are installed by spreading the lock and rotating it into the piston pin boss. Wire locks are installed similarly, but require chamfered wrist pins. Wire locks tend to spread side loads over more of the piston pin boss area and are considered to be a stronger pin retention method. Hook wire locks have an integrated hook at the end gap to prevent rotation within the lock groove. Tru-arc locks fall between these to and can be used with the stock sharp edge wrist pins’ the advantage of tru-arc locks is the ease of installation and reusability (spiro locks cannot be re-used). However, tru-arc locks are only recommended for lower horsepower applications.

• Can be used with stock sharp edge wrist pins
• Carbon Steel Tru Arc Lock
• re-usable