I have been told i should instruct my machinist to allow for a little extra clearance for jet boat applications. What does everyone else think? is there a general rule of how much clearance above normal to use? We don't really have any good boat motor builders in the area so i will need to tell the auto machinist what the specs should be.. also do i need to allow more for hyperutectic then for forged?
That's correct, the boat block due to running colder wont expand as much as a auto.As far as Hyper pistons,there suppose to hold there size better than a forged.I tried Hyper pistons in my Harley (air cooled)had a bad experience.Can't say for a boat app.
any idea how much? My buddy says 9-10 thou. for hyper pistons but that sounds like a lot to me..
thanks
Tahitijet, you have to determine what material your piston is made of and to set clearances accordingly. Call the pistons company and they will tell you what.
Tahiti,
Hi, I would run only forged pistions if you can afford them as far as cyl. wall clearance abouy .006 thou but ck w/ the piston manufacturer.FORGED because if you EVER plan on running NO2 you will need them.
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