Pistons

[neonnblack]

Ok question here, this is out of my knowledge range so here it goes: I know the difference from a cast and forged piston, but, can you custom turn pistons on a lathe from a block of aluminum? would it end up weaker then a regular cast piston? or right in the middle of the to?

 

[Chevelle.chris]

There is so much metallurgy that goes into designing a piston I doubt that you could mill / lathe one out that would compete strength wise with something a reputable piston manufacturer makes. If you had some odd ball motor that nothing at all was available for you could mess around with it, with the understanding that if this part breaks on a running motor, bad things happen.

They are designed to be light yet strong, and expand properly when heated. Most of them are not round cold from what I have been learned, because the way they expand when heated.

What do you need a piston for? You could get your bore measurements and start digging though catalogs to see if something can be adapted from another motor.

On the other side, if I had a lathe, and the time, I would probably give it a shot if I didn't care about the motor.

 

[larry_g]

Ok question here, this is out of my knowledge range so here it goes: I know the difference from a cast and forged piston, but, can you custom turn pistons on a lathe from a block of aluminum? would it end up weaker then a regular cast piston? or right in the middle of the to?

Tell us the metallurgical makeup of the cast piston, the forged piston, and the block of Al your going to turn the proposed piston from. It is possible to have a cast piston stronger than a forged piston, depending on the makeup of the metal you use.

Can you explain what you know about cast and forged pistons and why you think a turned piston would be in between strength wise?

lg
no neat sig line

 

[neonnblack]

well, i dont really need it. But the mitsu 3.0 motors have one manufacturer (that i know of) of aftermarket pistons and they are OUTRAGEOUS. i was jsut curious if this theoretically could be done.

 

[neonnblack]

Can you explain what you know about cast and forged pistons and why you think a turned piston would be in between strength wise?

lg
no neat sig line

i just know basic thing, not really anything metalurgic about them. and being in between was just a wild guess, nothing factual. like i said this is out of my knowledge range. just curious about it.

 

[George in Rancho Cordova]

Most aluminum pistons arte not round.
They are "cam ground" meaning they are somewhat oval when cold, becoming round at operating temperature.

 

[Murphy4570]

well, i dont really need it. But the mitsu 3.0 motors have one manufacturer (that i know of) of aftermarket pistons and they are OUTRAGEOUS. i was jsut curious if this theoretically could be done.

Call Arias Pistons. They will manufacture a piston for any application you can dream up. Prices were around $100 a pop for custom stuff last I checked. That was years ago, though.

 

[rsanter]

Yes you can custom machine pistons from billet stock and I have done it for special applications.
Forged is stronger because the forging process makes the grain structure follow the form of the piston as well as work hardening them at the same time.

Cast is weaker because billet material will have an inherent strength that you cannot obtain from casting alone

Someone said that pistons are not round, and this is very true. They will be round when at operating tempature. This is because of the differences in wall thickness from the area of the pin bosses.

If you need a special piston for a specific application you can buy unfinished or semi finished pistons from some manufactures.
When building a custom stroker, you can get pistons with no pin holes and then put the pin holes where you need them.
If you need a piston for an oddball application then you can find a piston of a similar style and similar size (including overbore sizes) and get them without the pin hole and the put the pin hole of the size you need at je height you need.
Some times you can find a piston that will work but the pin is too small so then you cab bush your rods and go to a floating pin.

In fact there are companies that do exactly what I am saying in order to make pistons for very rare engines

Bob

 

[djjsr]

Billet aluminum pistons are common in NASCAR and NHRA Pro Stock.

Link to more info .........

http://www.dragtimenews.com/Billet_Pistons.htm

 

[LigouriRd]

well, i dont really need it. But the mitsu 3.0 motors have one manufacturer (that i know of) of aftermarket pistons and they are OUTRAGEOUS. i was jsut curious if this theoretically could be done.

What specific application? I know that Wiseco makes forged 6G72 pistons and it would not be that difficult for them to make up a custom set for a later model engine.

 

[Kevin54]

You could turn them if the aluminum was the right alloy. Most pistons are a nickle aluminum allow.

 

[pop pop]

Of interest, cast pistions have a ferrous plate cast in the side of the pin hold area to prevent "creep" at temp.

 

[Primered Thunder]

Most aluminum pistons arte not round.
They are "cam ground" meaning they are somewhat oval when cold, becoming round at operating temperature.

This is 100% correct. I only know this because I worked with Mahle in the past on numerous projects that use purpose-built CNC machines that were used to turn (not grind) the "ovality" in the piston profile. If pistons are machined "round" at room temperature, they will NOT be round when the thermal deviation kicks in at operating temperature due to the wrist pin cross-section having different aspects of heat transfer versus the piston body.

 

[lametec]

J&E, Aria, Ross to name a few. All of 'em will make any size/shape piston you want, and they're typically not all that expensive. Not as cheap as an off the shelf set of cast pistons, though, obviously.

 

[adam728]

Check Summit Racing. Looks like some low priced pistons there for that engine
http://www.summitracing.com/search/...e/V6/Make/MITSUBISHI/Engine-Size/3-0L-2972cc/

As everyone said, pistons aren't round. And the amount of "cam" shape to them is often application specific, and many are bell-shaped from top to bottom as well.

 

[nso123]

We use Ross pistons in everything from street applications to race engines. There is a whole lot more to a piston than just machining it to fit. Placement of the rings, gas ports (if applicable), etc. The pistons are designed for specific applications, so a naturally aspirated piston is not the same as a nitrous piston and so on. I would personally just call and get a set made up. Ours run about $100 a piece for custom pistons when we get them from Ross.

 

[FastKat]

CP Pistons is a semi-low-cost manufacturer that will also make you custom pistons. Most of your other aftermarket piston manufacturers do customs pistons as well.

 

[Mmfh]

It could be done, but for that engine not at all worth it. I don't think there is any way you could come up with a long term solution without the years that went into research figuring what a piston needs to survive.

Could be a fun project though. I used to use a company called Jans, or Vaniolia to make custom ones I needed for racing.

Cool idea though.

 

[spv]

I am currently having a set of custom pistons made. I have communicated with CP, Arias, JE and Mahle. CP and Arias have been fantastic. Fast response and A+ service. JE took a week to respond to tell me I had to use the local reseller at X times the cost of buying direct. Absolutely hopeless from JE. Mahle did not even respond to my communication, so they fail as well. It is now between CP and Arias. You won't get a custom piston for under $150, but more like $200ea without coatings.

 

[FastKat]

This is unorthodox approach, but how about buying a used piston? If you find someone with a junk/core/parts engine, you'll be able to get it for peanuts. Plus, you know it'll be correct. Yes, there are disadvantages, but cost isn't one of them. This isn't for a race car or anything, right?

 

[rsanter]

Step 1
What is the one company that makes aftermarket pistons charging??

Step 2
What are you trying to do? Hop it up? Build it stock?

Does the manufacturer offer replacement pistons you can use?

Step 3
What is the bore you need and the pin height?
Can you find a similar piston from a ford, chevy, Toyota, etc?

Bob

 

[neonnblack]

ok ok ok, allt his was more theoretical not so much im going to be doing something, i was just curious if it could be done. thansk for all the responses though