Could we discuss piston mfg methods and designs 1

[bob1111]

We build race engines here and considering stepping into custom piston mfg. This may or may not be feasible but it has brought on some new questions as to piston design and mfg methods.

I would like to learn the forging method to creating the rough impressions of a piston. We are a machine shop so have not forged anything before. I am really trying to learn what the process is from start to finish.

Also, the question was raised about billet piston options. This would seem possibly a good blend between the irregular thermal expansion but strength of forgings and the brittleness yet thermal stability of the cast pistons. Is this not the case?

Could anyone offer some quality links or vd pertaining to the mfg of pistons or is most of this hidden art?

 

[swall]

Forging is not feasible for a small shop like you have described. You need a furnace to heat the blanks and a press to do the forging with appropriate dies for the piston form. Then you need a furnace for heat treating, a quench tank and a low temperature furnace for ageing.

 

[evelrod]

Besides, it's the least expensive part of piston mfgr. to farm out. Why bother?

Rod

 

[bob1111]

Yeah, as I understand it, many shops have another forging company do the forge blank and they machine it from there. That makes things more feasible fore our shop. We are certainly not a forging facility.

 

[PackardV8]

Hi, Viper,

I notice this has been asked this on a couple of fora and will certainly be getting similar answers. Of all the value-added opportunities in race engine building, trying to make one's own pistons is the least likely to be profitable. Don't even consider it. Do the research and even a little reading should convince anyone the investment in machinery and the learning curve is far beyond the reach of the individual shop.

thnx, jack vines

 

[tbuelna]

viper6383,

Not all pistons are forged. Some pistons are cast. It all depends upon the application.

As others have noted, there are lots of companies (Cosworth, Wiseco, JE, etc.) already making very nice forged aftermarket pistons. So you would have lots of formidable competition if you went into that business.

However, if your desire to learn about manufacturing forged aluminum pistons is mostly academic, then good for you. Here is a little bit of information:

Producing a set of matched, closed dies for forging piston blanks in aluminum is not too terribly expensive since the finished part is small, the aluminum material forges fairly easily and at low temperatures, and the forged geometry is not too complex.

The aluminum alloys used for forging are typically something like 4032 (hypereutectic) or 2618 (hypoeutectic). The blanks used for forging are cut from billet.

The finish machining of pistons requires some specialized machinery to produce the cam, barrel and taper profile of the piston outer body.

Good luck.
Terry