Pistons

[Alvor315]

I am in the planning phase for my next engine. I have been considering hyper-eutectic and forged pistons, and was really getting into the gritty details, when I came across a piston that is supposedly made from "Ultralloy." Ultralloy is an alloy of aluminum that has been supersaturated with a very fine consistency of silicon that is supposedly heads and tails above everything else. It is supposed to be nearly as strong as titanium, but weighs less and is less expensive. It sounds to me like a hypereutectic piston that is cut from a forged slug. Best of both worlds right? Is it just me or are these beginning to sound like a fairy tale? They are supposed to be available from HTC products, but I cannot find a company that sells engine parts and goes by that name. Has anyone else heard of these, or for that matter HTC?

A forged piston with near to nothing clearances? Ah the possibilities!

Let me know what you guys think.

Here is a link to one of the places that describes these pistons. It is an excerpt from a handbook published by Hot Rod Magazine in 2004.

http://books.google.com/books?id=zn...#v=onepage&q=ultralloy forged pistons&f=false

Al

 

[CNC-Dude]

When hypereutectics came out, everyone thought the same about them as being the best of both worlds too. They are just a fancy name for a cast piston nothing else. You just need to settle on what you are looking for as far as performance, and just look at either cast or forged, there really isn't much middle of the road here.

 

[Thad]

Reading the article in your posted link on right hand side in manufacture block (HTC) is shown as Hank The Crank website as "www.hankthecrank.com".

 

[Anlushac11]

There is a dfference between cast aluminum pistons and Hypereutectic aluminum pistons.

A cast piston is exactly that, cast aluminum.

Hypereutectic is a aluminum alloy that has a higher silicon content than is normally possible.In aluminum silicon adds strength the way carbon does in steel. They are much better than cast pistons but still not as good as forged pistons.

The Ultralloy says it is a Aluminum and ceramic mix. It either went no where since 6 years later it is not well known and it has not replaced forged pistons or else the military snapped it up.

 

[CNC-Dude]

There is a dfference between cast aluminum pistons and Hypereutectic aluminum pistons.

A cast piston is exactly that, cast aluminum.

Hypereutectic is a aluminum alloy that has a higher silicon content than is normally possible.In aluminum silicon adds strength the way carbon does in steel. They are much better than cast pistons but still not as good as forged pistons.

The Ultralloy says it is a Aluminum and ceramic mix. It either went no where since 6 years later it is not well known and it has not replaced forged pistons or else the military snapped it up.

Hypereutectic pistons are still made from a casting mold, they just use a higher silicon content than a plain cast piston does. Here is a description from Federal-Mogul's website explaining the differences between cast, hyper's and forged....

Piston Technology - Hypereutectic Pistons
•Federal-Mogul utilizes two manufacturing processes for the production of high performance pistons: Speed-Pro Hypereutectic pistons are cast in permanent molds, while Speed-Pro POWERFORGED pistons are extruded from aluminum bar stock. Each has advantages in certain applications, but there are cases where the choice is not an easy one. An honest evaluation of your needs will yield the most satifactory results.


•Speed-Pro's exclusive FM244 hypereutectic alloy is the result of extensive testing and development and has several unique characteristics. Unlike competitive products, this optimized metallurgy allows hypereutectic pistons to operate perfectly with standard ring end gaps, and conventional ring land locations. When compared to traditional cast pistons, which are not designed for performance use, the hypereutectics are significantly stronger, particularly in the highly loaded ring land, skirt, and pin bore areas. The FM244 Alloy contains 16.5% silicon, and has excellent tensile and fatigue strength. This material's improved thermal characteristics, it's greater hardness, and the increased resistance to scuffing permit tight bore clearances which help minimize noise on cold engine start up. This quiet operation, along with a lower cost are the primary advantages over a comparable forged piston. These pistons are an excellent choice for street performance, for "claimer" oval track engines, and for bracket racing use. They will also work well in moderate supercharged applications, and are especially suitable for towing and marine use.

 

[aussie7mains]

Hyper eutectic referes to the heat treatment of the alloy, the addition of higher silicon alloys the maker to trap the alloy above the eutectic point on the metals chart, which gives less expansion with heat, which would otherwise mean that the piston would have to be run with more cold clearance.
The higher silicon give some extra strength and fatigue resistance. the other way to limit expansion is with the autothermic arrangement where a steel strut is cast into the piston to hold it in the expanded state.
The outcome of all this is that the high silicon is better, but for the duty that most of us are likely to stress our engines to, it wont matter.
A7M

 

[rocklord]

Hyper eutectic pistons are more brittle than forged.
In a boosted engine, excessive pinging will crack a hyper eutectic piston, whereas the forge piston will deform.

Just a FYI for the guys wanting to use them in their boosted engine.

 

[Alvor315]

I have continued to look for these pistons. The "ceramic" I have found is still silicon. The difference that makes Ultralloy special is that Ultralloy is forged instead of merely cast, but because of its composition is more thermally conductive, harder, and can withstand more abuse than either cast hyper-eutectic or forged pistons.

I have not found much more about them.
I'm starting to get the feeling that this is some sort of elaborate prank. Every time I read about this alloy the sentence is always the same.

http://wattsshopperformance.com/pistons.html
A recent innovation is "Ultralloy", A patented ceramic- aluminum alloy
presently available. Ultralloy's composite products have unprecedented
uniformity in terms of thier size, shape and dispersion in the aluminum martix.
The new alloy's strength is on par with titanium, but parts made from it cost
less and weigh less.

http://www.ls1-australia.com/forum/viewtopic.php?f=31&t=304
A recent innovation is ?Ultralloy,? a secret patented ceramic-aluminum alloy presently available from HTC Products, a premier manufacturer and distributor for most brands and types of cranks, rods, pistons, and rings. The silicon particles in Ultralloy have unprecedented uniformity in terms of their size, shape, and dispersion in the aluminum matrix. The new alloy?s strength is on par with titanium (and costs less) and parts can be made much lighter.

Pretty much the same sentence comes from the link in my original post.

 

['68falconohio]

I know I read a thread on speedtalk.com about pistons and an aluminum alloy that was banned in F1 and other racing... I can't recall what the name of it was and I can't find the thread. I want to say it was an aluminum alloy with beryllium and something else in the mix.

EDIT: Found it... http://speedtalk.com/forum/viewtopic.ph ... d&start=45
I know this isn't specifically about forged vs. cast but it's a good read.

Stephen

 

[Anonymous]

If you think a high-silicon cast piston isn't much different than an ordinary old OEM cast piston, go to your local auto machine shop and see if they can give you an example of each from their tear-down scrap bin. Chuck the low-silicon version in a lathe and take a cut on the skirt as if you were re-sizing it; use a high speed steel tool. Then do the same with the high-silicon piston . . . and see what it does to the edge of your tool! Old two-stroke racers used to go through a lot of pistons, and would buy them as semi-finished blanks which they would finish to size at home, and the high-sil pistons were a b##ch to turn until you found the good tool steel, the best angles/feeds/speeds, etc.. The motorcycle factories in Japan spent a pile of money developing this technology starting in the late '60s, and generated a lot of scrap aluminum until they learned how to cast it successfully. By the early '70s an OEM piston for a Japanese bike worked better for the racers than the aftermarket forged pistons of the day.