What kind of piston-to-wall clearance can I run?
The factors that affect piston-to-wall clearance are cylinder wall thickness, whether the block is filled, the overall compression height of the piston, piston material and thickness, and whether a marine engine is to see fresh-water cooling. Most small blocks get .004 piston-to-wall clearance and most big blocks get .005 due to the use of our 2618 high-strength alloy. For heavy blower and nitrous applications, Wiseco recommends adding .001 to the standard clearance. Special note: Clearance numbers are obtained from measuring the largest diameter of the piston, typically at the bottom of the skirt. All measurements should be taken 90 degrees from the pin centerline.
Motorcycle/ ATV/ PWC piston clearances are printed on the label on the front of the piston box.
When I install my Wiseco piston, which way should the arrow on top of the piston face?
On most Wiseco Powersports pistons, the arrow will point toward the exhaust. If you are installing pistons in a v-twin or automotive application, this will differ depending on the application. Checking the installation directions included with your Wiseco product will verify the direction. But, if you still need assistance, our technical sales team will be happy to help.
I have a 4-stroke ring package that I received with my piston. I have the top oil rings, but am unsure of which rings are the Top and 2nd. How can I tell?
Some Wiseco 4-stroke ring packages are interchangeable between Powersports and automotive applications. Therefore, you may have additional rings that are not required for your application. In general, the silver/ gold/ shiny ring is the Top ring, while the black ring is the 2nd. This can be verified in the ring installation instructions included with your ring pack.
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