[bob1112]

We are looking at cutting our own pistons to cut cost and lead time for some of our engine needs. I would like to learn a little on what you guys thing about doing this in a job shop. I would like to look at comparisons between piston substrates and mfg methods.

Casted pistons - I am wondering if these can be produced with the correct properties to allow them to be as resilient as forged pistons. In our experience, casted OE style pistons seem to do ok but are usually replaced for bigger, higher comp ones and the replacements are almost always forged design.


Forges pistons - Do I understand this correctly that most companies buy forged "blanks" and machine these to size? What allow is preferable and should this be attempted in a job shop? We would likely turn them on a Hitachi live tool machine and possible do the other machining on a VMC.
Also wondering about the lubing grooves on the skirts, how one would do that.

Hypereutectics - I honestly do not know how they are made because we rarely use them at all. How are they made and can they be made economically?

[RICHARD ZASTROW]

You may want to study the geometry of finished pistons. They are slightly elliptical (egg-shaped) and tapered as well. This is to compensate for heat expansion that varies thru different cross-sections like the heavier area around the wrist pin bosses.

The lathes used to produce these shapes are specially made machines. Maybe you can locate a used piston lathe or retrofit candidate carcass.

Or maybe they don't make them that way anymore. LOL

Dick Z

add: www.omegapistons.com

add: Takisawa TPS 4000 CNC Piston turning lathe

[tstom]

they're still made that way but I believe the shirts are finished on some sort of cam grinder they are tapered as Richard says and the ring land area is aprox .030" smaller than the skirt
I don't mean to discourage you but I think you will find out pretty fast that you won't save much
I have been hearing about some billet race pistons lately but for as long as I've been doing this ...30+ yrs... they have been forged