Subscribe to Precision Engine
Sign up for our E-newsletter
Custom pistons are available in any configuration, but knowing what’s needed to order them requires careful measurement and sound decisions.
Once the data sheet is accurately completed, your order begins to forge blank slugs.
Initial machining begins with pin bore placement.
Here the rod small end passage is machined, based on your reported small end width.
With ring grooves machined relative to the pin bore and anticipated dome height, finish-machining will create the final skirt profile, dome and valve pockets.
A finished piston ready for final inspection.
Thanks to today’s CNC machining techniques, custom piston mass is extremely close in terms of weight.
A blank custom-piston data sheet from Diamond Racing.
A blank custom-piston data sheet from JE Pistons.
A blank custom-piston data sheet from Mahle Motorsport.
The valve pocket placement, radius and depth on this custom slug is based on a range of input, including valve angle and valve plunge (re lifter rise and rocker ratio).
Diamond’s chamber mold kit includes A-B epoxy, spark plug hole plug, gloves and a mixing stick.
Once the epoxy dries, it’s easily popped out (aided by release agent and the fact that the epoxy slightly shrinks as it sets).
When an extremely short compression height is needed, the pin bore may intersect the oil ring groove, in which case a set of oil ring support rails are needed (available from the piston maker).
Once in the piston maker’s hands, the mold is digitally scanned.
This finished piston was made using the epoxy mold as the reference.
Tags: BILLET, CNC, CUSTOM PISTON ORDER FORMS, CUSTOM PISTONS, DIAMOND, J&E, PISTONS
