Microcast piston question
 

Can anyone comment on the advantages that the new Microcasted pistons provide and exactly what it means. I have a motor that has this and a friend and I have been discussing this and just wanted to know what the big deal is with it.

thanks

Re: Microcast piston question
 

This technology givers ability to add Silicon in quantity more then 22-23%. It is pretty old technology ( as far as I know). Also been calling poweder metall technology. If you look in internet, you will find it is widely used for years. It has some advantages and disadvantages. From what I know this techology been use in engine for military aplication in Russia since 1980"s. We try and used this kind of materials for pistons back in 80's and 90's but later it was find the way how to make casting alloy. Alloy made by this technology is still bridall.
One of the big advantages is-economical-you can form almost any kind of configuration without wasting machine time and material ( it is beside Si content).
more info you can find on the web.
Edward

I might be wrong, but from what I know. In the past some of the pistons were machined from aluminum bars . Nowdays they are casted, giving the advantages of lightness and complicated intrisic design possible. I am not sure whether you can use powder metal technique because I think they can only use one type of metal and it is not the type of aluminum alloy we use in RC engine, it looks more like steel or iron.
The biggest problem with casting high silicon content alloy is getting porosities in the casting. Si particles don't disperse uniformly in alluminum. To control the particle size it has to be heated to a certain temp, let it cool down at a specific rate.
But it is all aluminum manufactured secrects.
A newer technique is spray forming process which give you high density Si-Al. It can incorperate upto about 50% Si. but the piston will cost more than an engine you can get now.

This is the one of the reasons ( secret of casting) we will never realiese and ( as I noticed-you are pretty familiar with airmodeling) you will know what Russian piston material is.
About poweder Al alloy with 35 % Si, I can supply you by tons, with realy good dispersed Si in alloy, but it is not going to work as material we use on our engines and P/S sets.

ok. I'll bite, so why would the newest engines use this technology? There has to be some advantages to it.

First of all, we tryed about 20 years ago and since we found different way to make what we want to, we never went back to that type of metalurgy. Second, why just this year Novarossi makes AAC, and AAc very well known for last 25 years?
Why would I make my own engine and don't buy Novarossi ( it is much easier, just pay $300+ and be happy for while)?
They probably developed something new, I guess.
Everybody choose their own way.
:D ;)

Ok, we are not really interested in knowing why you don't use this technology in your engines. What I would like to know is what if any are the advantages in the engines that are made with this technology. This seems to be the newest trend from Novarossi and it seems that no one knows just excatly what the deal is other than it's New.

:sneaky:
I am very interesting in everything, specialy if it is realed to metalurgy.
I didn't have chance yet to work with any of those pistons, but all development in piston materials is to improve expantion rate, reduce friction, improve stability of piston geometry under temeprature, reduce wear and make naterial more durable.
To achive all this points ( except durability) in one shot, nees to increase Silicon content in Alloy. Novarossi using this way to do so.
I think it is pretty simple.
Oh, forgot to mention big part of it-marketing;)

From my understanding/discussions with local importers here the main advantage being touted is that these types of pistons can take more heat before they get out of the usable range. These engines can supposedly take up to 150 celcius before damage starts occurring.

Any Al alloy can take way more then 150C before they start damaging. 150 C isn't critical temperature.
On tether cars, when they come from race, temperature some times reach up to 420 F.

I dont race my R40 on a tether.

My buddy pointed me in this direction which talks about Hypereutectic pistons in full size engines, is this what Microcasting is all about?

Contains 12.5 percent_or more silicon content. Special melting processes are necessary to ‘super-saturate’ the aluminum with additional silicon content. Special molds, casting and cooling techniques are required to obtain finely and uniformly dispersed silicon particles throughout the material. Our hyper-eutectic material is also being used in light and medium diesel engines to replace some of the eutectic pistons with iron groove inserts used for additional heat and wear resistance of the ring groove. Heat and wear in the ring groove contribute to groove ‘pound-out. In the Sealed Power hypereutectic pistons, the hard, finely dispersed silicon particles serve as ‘micro-inserts’ at the surfaces of the piston, especially in the surfaces of the precision-machined ring grooves. The increased strength, heat and wear resistance provided by the high-silicon content hypereutectic piston material allows for elimination of the groove inserts in several piston applications.

Hypereutectic
 

Resuming what has been posted, and talking with some people in the business, and explaining it with simple words.
These "new" MCP pistons used by Novarossi or others, can sustain better the higher temperatures posed by the high rpm's at which they operate, without loosing performance. Of course they bennefit from it for marketing purposes, Am I right???

AFM

afm:


I think that's what we are truly trying to find out.

Are they really better or is it just marketing hype?

I have been talking with a friend who races SCCA and knows a great deal about building real engines.

From what I have told him about the high Silicon content, he believes it is a variation of the hypereutectic form of making pistons for real engines.

Best to worse in this order for real engine pistons.

Machined
hypereutectic
cast


We also discussed what it really buys us in the RC world since our engines work off of taper. We kinda concluded that yes, the piston may be better than a typical cast one but the sleeve is still the same so you might not gain that much of an advantage.


Who knows, we could be way off base. maybe someone can confirm or discredit it.

From our expirience, piston material is one of the most important element in engine performance. Yes, sleeve material is important too, but I personaly preferd to put in front of everything Piston material.
I am sure you saw already that most of the latest engines ( in RC cars) are used Brass sleeves and only one thing is realy changing is Piston material ( I am not talking about latest work from Novas and Sirio on AAC).
From thousands experiments in Former Soviet Union was found, much better result (performance and reliabilty) are comming from not brass, but from BRB and AAC. As I explaned in some other thread, there are some realy "hot" disadvantages of AAC on particular engine' arhitecture.
So to stay on low cost of manufacturing, the best way is regular brass for sleeves, but the best results been done on BRB so far.
I am not familiar with real engine manufacturing, but I am sure it is realy different aplication and not everything may be just small things can be apply to our engines.
No words about technology of casting pistons;)

I have tried the difference....
 

I had Novarossi NS12S3 (CLASSIC PISTON) AND THEN NSR12S3 (MICROCASTED).
A lot of friend of mine raced this last months with these two engines...... and we all have THE SAME "IMPRESSION" (
It is difficult to say :( :( :(
....but the microcasted piston .... that is presented from novarossi as more durable:lol: :lol: :lol:
It last much less that the classic tipe of piston:mad: :mad: :mad: :mad:
Maybe Novarossi had something to correct in the microcasting process.... but this is the reality.
Novarossi .12 microcasted worn more quicker than the classic type NS12S3!!!

:flaming: :flaming: :cry: :cry:

Re: I have tried the difference....
 

:nod:

Re: I have tried the difference....
 

Putting aside the durability issue, did you noticed any performance difference between the two types???? Or they perform similarly.

AFM

Putting all this into a single list plus some

Novarossi's Microcast we believe is a Powdered Metal technology. yes it is common to use alumunium with higher silicon content than can be conventionally casted with a molten alloy. PM provides better dispersal in most cases of the silicon component therefor making the piston harder and more stable.

Hypereutetic and eutetic alloys are similar to what has been used for years as a high silicon content 5/6/7 series type alumunium and silicon dispersal becomes difficult above 23%. Remember SI makes it growth stable and wear resistant but reduces ductility.

Duralcan or Duralumunium is what I believe was being used prior to novarossi's microcasting but I cant be 100% sure.

so all that being said is one better than the rest?? that depends.

yes and no.

you will also notice if you study alot of engines that tapers on the liners change from time to time as does the hone finish on the liners depending on what is trying to be accompolished. You would be suprised how much minor measurements change within runs of one engine. This is the little stuff most people don't know to look for and the difference is a rocket or a turd.

The bottom line to all of this for anyone involved in production engine development is.

Will the engine maintain compression at temp with minimal piston to liner drag, minimal piston mass and survive a reasonable lifespan without exploding.

All that being said
Bottom line is this how good is your engines compression cold after the piston to liner pinch has faded, then how good is it after it is shut down at 250 degrees. If its as good hot as it is cold then the thermal expansion of the piston liner and case is a well balanced combination. The trick is to make it last that way the life of the engine. This will allow the engine to rev hard and have maximum pop off the corners with a stable Idle. That is the bottom line no BS answer to the question you asked and what all the engine manufacturers are looking to achieve

A hard structural bronze with berullium added as a structural stabilizer with a high SI content piston is desirable as TG 777 is producing. The only downside is Berullium is expensive and it is toxic if you were to inhale the dust when grinding on it. Kinda like asbestos (Model boaters know this as we use Berullium copper propellers and take appropriate cautions when preparing them)
I personally had never considered using berullium as a liner material before but it does make sense due to its structural properties (TG nice work) However don't expect to see it in high volume production soon as it is quite cost prohibitive.

I personally have been considering some piston coatings recently in leiu of high Si content. (vapor deposition technology has drastically improved in recent years)

On a sleeve type engine I would not even consider AAC as there are to many draw backs with an alumunium sleeve on an alumunium case particularly aluminum fretting and brinelling causing glow plug contamination.

TAW
an interesting technology we developed to reduce ring pound out even with Hypereutetic pistons was groove welding and remachining. It is used extensively now in the auto industry.

Motorman: Thanks for the info, that helps explain the technology.

now......

I feel like I have jumped off the diving board on the deep end and can't get back to the top.

Bottom line:

Is this microcasting a bunch of crap of does it have merit?

Can anyone answer that?

I don't want to spend $250 for an engine for it to be a dude. Nor do I want to sacrifice longevity for that extra little 2% performance gain.

Rodney,

the engine that I sold to Troy is the fastest .12 I ever laid my hands on and a LOT of people came to me after the race I ran it in and asked me where they could get one.
This motor was faster than any modified .12 I have ever seen, maybe except Swauger's at Ft.Myers.

What makes you think it could be a dud?

No matter what the pro's opinions are here, the microcast piston seems to work very well in this particular set up and all the theory you are asking for won't change a thing.

Hey Stefan.

good to hear from you.

I agree, Troy's motor you sold him is very strong. My definition of a "dud" was if it won't last very long then that's not good for me.

Some folks are already saying that they don't even last as long as the normal P/S.


Just wanting to get all the info I can before buying my next engine.

l

Coments
 

Hi Dennis. I agree with you 100% on everything. Actualy yuo finalize what I was putting in different treads around.
In our opinion, that microcasting alloys will not add a lot of power.
As I mentioned before there is techology to cast AL alloy with desirable properties and in combination with right leaner material and right tapering it will improove performance tramnedosly.
Yes BRB is very expencive material. but so far we are manged to have at reasonble level. I am not planning to flood with BRB sets, it is my hobby, I love speed and performance and it is so much difference in performance between brass and BRB, hard to belive.
About AAC-in conventional design engines it is totaly nonsence to use it ( it has been prooven years ago) and I have mentioned in the past the reason for it. We discover this interuption back in 1990's.
This is why we came to design Palmaris PS12. I don't have parts which are vibrating and creating AL debry and light up in combastion chamber raise temp, burnglow plugs etc).
I am sure pretty soon more brands will come up to the same schematic ( ones they will find the way how to cast cilinder).

Well on this question, will be very dificult to answer.
Novarossi very popular brand and to stay on the top, they have to make improovments preety often or they will loos their positions.
I am sure you saw JP's flying and screaming, but also I am sure you saw ( I saw many times) when JP was slow as HPI.
On other hand, I will not sugest to compare team engines to regular poduction engines. Ths is why they are team egines-drivers will show you how fast they are, but pretty often it is driver, not an engine.
Bary Bekker won Speed Line in Las Vegas on Sirio ( I belive this info was correct in other tread) and he was running against Newest team X12 JP ( Mike Swager) and other guys who used newest engines.
So who can answer you this question?
I personaly don't belive in Microcasting, but I might be wrong.
We never were able to get out of powder Alloy results ( not in performance , not in life)which we got from our casting pistons. And it was spent years of trials.
BTW, I am changing conrods after at list 3 gallons of fuel first time

to prove what i said, picture of piston with traditional casting and other advanced process.

sorry how do you post pictures

in the post reply window(the windows after you hit post reply), there is a attached file boxed at the bottom. Scroll down and you should see it.

Re: Re: I have tried the difference....
 

Well, I will be sincere:rolleyes: :rolleyes: :rolleyes:
It seems to me that there isn't much difference of power between them.
It seems to me that , after one hour of use, the microcast is more "powerful":confused: but i think more probably is my impression beacuse I bought a new engine after some months of use of the precedent (ns12s3 not microcasted).
TO BE CLEAR:
Now I have purchased the set piston + sleeve NOT MICROCASTED.
BECAUSE :
IT IS CHEAPER (20EUR LESS)
i THINK IS MORE DURABLE......

:batman:

Ciao Mario.

That's just what I've been thinking, I have a NSR12S3, that I bought in Dec. after about 2 1/2 gallons it lost performance. I put the Rex counterpart microcast piston and "fanged" sleeve, mine ,ust've been an early model because the sleeve looked like a MR12's sleeve. It's taken awhile to break in, but it's really coming around now after about 10-15 tanks:nod: .

The best thing I've found about this P/S combination,( the micro cast piston and whatever y'all say the sleeve is made out of), is that if you die in a race, when that muther's hot, it fires RIGHT back up and runs well.

Totally agree, speed is a combo of car/engine/driver. The Nova team engine does has better piston and liner fit. Then it also wears out quicker. The internal crank case is polished as weel. I doubt that will yeild noticeable difference in real life.

A top of the line Max today is not much difference to a team Nova. We can buy the horsepower. Making use of it is a different thing!

Serpent says their MCP engines run better in the long race configuration, that they handle the heat better, blah, blah ,blah.

What temperature is too hot for these?

:cool: I'm getting ready to race in sunny Florida and don't want to burn it up.:tire:

The Red,

We were temping them at just over 200 last weekend after a 5min run. We had one of those weird unusual days were it was just as hot as Florida.

Hope this helps.

:weird: :weird:
can you explain me better what you have "discovered"?
do u say that microcast piston and classic sleeve suffer the hot temperatures less ..... or are more powerful in high temperature...???

What is the best piston+ sleeve couple for this hot summer???:flaming: :flaming: :flaming:

I would say the best piston / sleeve /conrod for the NR based engines is Edward's (Palmaris) BRB set.

Guess what guys... Nova is reworking the AAC engine now. The 8 ports is not working for them. They are going to switch the 421 back to ABC in the mean time!

Sorry, but it is very old news. :nod:
One more time-expirience of trials and mistakes. They didn't learn it from 20 years ago.:D ;)

Hi Stefan. How is going?
Did you try last one?;)

I just meant that it was easier to re-start when hot than other non MCP engines.

Last weekend, like I said, on about the 10th tank, in near 90 deg F, air temp, it was running 260. Blowing good smoke, and starting to get fast.

About right?:blush: