piston resizing

Dan Timberlake · 11-08-2015, 08:01 PM

Quote:

Originally Posted by Mike Pearson

They are for a 4.075 bore now. I would like to go down to 4.065 if possible. That would be .005 off the radius.

Piston skirts are usually not cylindrical. Some times they are some combination of tapered, cam ground, barrel shaped.
I wonder if JE can resize them.
https://www.jepistons.com/Catalogs/Automotive/NHRA.aspx

As others said, the ring grooves may need deepening. I don't think that can be done without the ring seal suffering,

Adger Smith · 11-09-2015, 02:40 AM

Call Frank Parks. He has started doing pistons for the Nostalgia Dragster crowd. He might be able to give you some advice or even do what you want.
His Son Scott is very talented and can do just about anything with a CNC.

Mike Pearson · 11-09-2015, 10:09 AM

Quote:

Originally Posted by Adger Smith

Call Frank Parks. He has started doing pistons for the Nostalgia Dragster crowd. He might be able to give you some advice or even do what you want.
His Son Scott is very talented and can do just about anything with a CNC.

Thanks Adger. Can you send me a Pm with his contact info or text to 813-433-4742

RonP · 11-09-2015, 02:00 PM

Hi,
Normally, OEM piston skirts are tapered horizontally and vertically.
The top land is also tapered from the chamber down to the top ring groove.
All the land diameters are specially sized too.
Ring grooves should be adjusted appropriately as well.

Trying to resize the piston will be difficult with the center boss removed.

Resizing a piston without a properly tapered shape would be a concern for scuffing,...especially for high rpm, high load applications.

Thanks, Ron

11-09-2015, 02:40 AM	#2
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: piston resizing Call Frank Parks. He has started doing pistons for the Nostalgia Dragster crowd. He might be able to give you some advice or even do what you want. His Son Scott is very talented and can do just about anything with a CNC. __________________ Adger Smith (Former SS)

11-09-2015, 02:00 PM	#4
RonP Junior Member Join Date: Mar 2003 Location: Detroit,MI Posts: 81 Likes: 28 Liked 29 Times in 14 Posts	Re: piston resizing Hi, Normally, OEM piston skirts are tapered horizontally and vertically. The top land is also tapered from the chamber down to the top ring groove. All the land diameters are specially sized too. Ring grooves should be adjusted appropriately as well. Trying to resize the piston will be difficult with the center boss removed. Resizing a piston without a properly tapered shape would be a concern for scuffing,...especially for high rpm, high load applications. Thanks, Ron