FormulaBoat

iTrader: (1)

On the Summit Pro LS pistons, which are supposedly Wiesco, there is a recommended wrist pin upgrade if you are approaching 1000hp. In the 2015 Wiesco catalog my machine shop had, it said to use these at 700hp and higher.

Summit and Wiesco both have them, the Summit ones were slightly thicker.

Here is a visual of the as-supplied pins vs the meaty Summit pins. I hate to be slinging the extra weight around, but….

Length and OD are the same, just looks not in the pic:

Che70velle

iTrader: (6)

Wristpin is the number one most abused part in the assembly, even more so than the rod bolts. There’s a million options regarding pins, and it all boils down to usage. Obviously lighter is better. If a beefy pin is needed (more mass), look into Ti pins. You can get them coated. Casidiam is very popular with coated pins. Those get down in the 65 gram range.

pannetron

Some pistons (CP) move their pin bosses inboard so they use shorter pins to keep the weight down.

Summitracing

Hello, generally we use the upgrade pins when we push past 1000whp or use a 300 shot of nitrous or greater. RPM is another factor and we rate our pistons by piston speed due to the variety of strokes that are common. What kind of stroke and rpm do you intend to run. Also, because marine is basically pushing a wall of water for minutes at a time, we recommend the 9.5:1's even when a better fuel is run. Please let us know and we can home in on it further. Thank you.