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Pistons alloy which one 4032 or 2618 for street with heay mods.

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Imh0TeP

20+ Year Contributor
35
2
Dec 26, 2002
Caguas, Puerto_Rico
After a failure of 2 JE pistons in my ride I decide to learn about "what was going on in there" the trust on Tuners is a big issue. But that is another history.

I decide to search and ask to the experience ones about pistons, but in a deep perspective about which alloy will be "the one" we must consider depending on our goals on the street or track. Money is not considered at this time because the range of cost between this 2 alloys. Horse Power/boost in range of 400hp or +15lb boost. Goal "Street Dary Driven punched gas several times a day"

Which one? Is logical always to look 2618 because its strength, But! if are bad bored or wrong cylinder/wall gapped will have more risk to fail premature, because the alloy expands a more and will be near or touching the cylinder wall on simple terms... the 4032 that one many said the cheaper is "more rigid" because the 11% more silicon alloy that avoids to expand, and many brands have it coated.

If a car is on dairy drive will heat-expand / contract-cooled so what choice? Virtues and risks. -What don't do-? Or what to do with witch one?

Forged pistons are generally made from one of several different aluminum alloys, with each offering different benefits depending on the application. The two most popular alloys are 4032 and 2618. Speed-Pro typically uses VMS-75, which is fairly close to 4032—both contain about 11 percent silicon, which helps with ring groove and skirt durability. These are the best choice for applications expected to have decent longevity, such as street vehicles and entry-level bracket racing and oval track combos. Although 2618 has better high-temperature characteristics, it contains virtually no silicon. This material expands and contracts more, so greater bore clearances are needed to prevent scuffing. Pistons using 2618 are best suited to nitrous, blowers, or higher end race applications where frequent inspection and replacement are not a problem
http://www.carcraft.com/techarticles...ng_technology/



The 2618 FORGED ALUMINIUM ALLOY (JE,ROSS,WISECO,CP,ARIAS)

Pistons using 2618 are best suited to nitrous, blowers, or higher end race applications where frequent inspection and replacement are not a problem.
(http://www.carcraft.com/techarticles...ng_technology/)

may wear a bit faster but provide better strength and durability. In the rare case of a crack in a 2618 piston, the crack will migrate to an area of lower stress and stop. 2618-alloy pistons keep their shape under extreme pressures and high RPM's.
(http://www.stealth316.com/2-pistonguide.htm)

The "2618" performance piston alloy has less than 2% Silicon and could be described as Hypo (under) eutectic. This alloy is capable of experiencing the most detonation and abuse while suffering the least amount of damage. Pistons made of this alloy are also typically made thicker and heavier because of their most common applications. Because of the higher than normal temperatures these pistons experience in their usual application, and also the low-Silicon content allowing the maximum possible Aluminum heat-expansion, these pistons have their cylinders bored to a very loose cold-fit. This leads to a condition known as "piston slap" which is when the piston rocks in the cylinder, and it causes an audible tapping noise that continues until the engine has warmed to operational temperatures. These engines should not be revved when cold, or excessive scuffing can occur
(http://en.wikipedia.org/wiki/Hypereutectic_piston)


The 4032 FORGED ALUMINIUM ALLOY (ARIAS,MAHLE,SRP)

These are the best choice for applications expected to have decent longevity, such as street vehicles and entry-level bracket racing and oval track combos.
(http://www.carcraft.com/techarticles...ng_technology/)

have great wear characteristics because the silicon particulate hardens the alloy and reduces the thermal coefficient of expansion. However, silicon-aluminum alloys can turn brittle and become prone to fracturing when subjected to extreme stress. With a piston made of a silicon alloy once a crack starts, it doesn't stop until the piston suffers a catastrophic failure
(http://www.stealth316.com/2-pistonguide.htm)

The "4032" performance piston alloy has an approximate Silicon content of 11%. This means that it expands from heat less than a piston with no Silicon, but since its eutectic level of Silicon is fully alloyed on a molecular level, this alloy is less brittle and more flexible than a stock Hypereutectic "smog" piston. These pistons can survive mild detonation with less damage than stock pistons.
(http://en.wikipedia.org/wiki/Hypereutectic_piston)

Another option for a daily driven vehicle that isn't going to see over 10 psi, is MAHLE. They are a well known german manufacturer that makes piston for Ferrari and F1 teams. Very well designed and quality made piston, but unfortunately they are made from 4032 alloy, which isn't as strong as the 2618 that the other brands are made from.
(http://www.svtperformance.com/forums...d.php?t=181225)

Here is Another Information about Piston Coatings, Gaps, Bores, and diferences on 2618 and 4032 alloys:
http://www.aa1car.com/library/2005/eb60522.htm
http://www.jepistons.com/dept/tech/d...instrc4032.pdf
http://www.jepistons.com/dept/tech/d...instrc2618.pdf

Thanks Guys For your time.
__________________
 
Last edited by a moderator:
what exactly caused your pistons to fail?
two different rebuilds? or two at a time?

I think a lot has to do with people tuning,
some of these logs have horrendous knock,
no wonder some people get damaged parts!


edit:
now that I see your piston/head, I agree way too lean(new injectors for sure)
 
I like Ross or wiesco pistons. Proven durable on the street and track. Just make sure your piston to wall clearances are not to loose.
 
I like Ross or wiesco pistons. Proven durable on the street and track. Just make sure your piston to wall clearances are not to loose.
Watch out for Wiseco's there have been issues with them cracking skirts. With no scuffing, wear, or improper clearance so dont get deffensive please :) Ross proven time and time again.
Bryan
 
These are some pictures of the JE.20 pistons (2618), and the link above shows car details and modifications,

Some ones said was too much timing , another's wrong cylinder wall clearance . Is a dairy drive car with aprox 6700 miles. Only 2 times was race on track. Was tuned on dyno 7 days before go to track. Run at 820C egt. 22lb boost 93 octanes. What goes wrong?

http://xiec.netsolpr.com/talon/status.htm

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whats dary or dairy drive?

Anyway, let me dig into this a little. I have always been a Manley piston fan, but never really dug this deep into it.
 
I am saying this as nicely as I can... But, those look pretty MELTED. The Greyish stuff on the top of #2 bore is melted/boiled piston. It looks very severe and seems to be in one cylinder. I am not standing there to look at it, but if it is only one cylinder... You probably have an injector or injector wiring fail.

Your quest should not be for pistons at this point. Put a set of Ross (I preffer) or other name brand in there and fix your lean/ detonation problem. This is not a defective piston problem. The melted piston is a side affect of your other problem.

Good luck to you,

Jake
 
You ran very LEAN in that cylinder. A good set of Wiseco's will do you good as long as you fix your lean problem.
 
Is So true, i never realize can be a faulty injector or injector conector. the injectors are RC, did can come defective? or --- (can be programed purposly to do the fail?)---
 
You might have an ecu problem as well, causing one injector to run lean (not common, but something to make sure of). Yes, I'm sure that you could have bought a bad injector also.
 
There's nothing you can do tuning-wise to lean out only one cylinder. It's highly unlikely that one injector driver circuit in the ecu would fail and nothing else. It's probably a defective injector, clogged injector, wrong flow rate injector, bad wiring, etc. You can have your injectors flow tested and rebuilt. In fact you should, even though it might cost as much as brand new injectors. Otherwise you won't know if your actual injectors are bad or something further up the line like wiring, resistor pack, who knows.

The spark plug in that cylinder would have told the story too.

Get a datalogger at the least, and monitor your knock. Something like that would have been off the scale.

Next step is custom chip, like Keydiver, set up to show knock on the stock boost gauge. That will keep you safe if this problem happens intermittently.

Better yet, dsmlink, which will give you all that and more.

Do NOT tune blind, especially if you can't listen for knock.


PS: We say "daily driven" (adjective) or "daily driver" (noun) or "DD". Dairy driver is a milk truck driver ;)
 
Thanks Guys,

I will check al the harness, the detail is when i disassemble i don’t mark the injector of that piston :mad: i need to check all but how? They are brand new RC 1000cc that ones form ebay. RC is a good brand.

on the injector sheet one injector have specified with 996*cc of flow the rest ones more than 1000cc mus be that one. on the sparks and ignition well is a issue with magnecores they do not click well on iridium sparks because i use before a bigger spark how i can explan... erm. There is 2 types of spark nuts the big one and the little one not sure if are 5/8 the big one ect. The detail is that one is taller and the sparks with the little nut like the iridiums are shorter. The magnecores was use first with the taller ones a (v8ev) some like that later i switch to iridium’s that are shorter and the magnecores do not click on them well.


Seems ill co with 2618 Arias, depending fo the time and cost ill coat the skirts and or top of piston
 
You wanna send your injectors to RC or another rebuilder for flow testing, cleaning and flow matching. A few cc's on the flow chart would not have caused your problem (assuming they actually sent you what's on the flow charts). More likely one injector got clogged.

Ignition issues are very unlikely to cause detonation. Misfire yes, but that's not dangerous.

As for pistons, I would just replace the melted one with the same type, or if it costs just as much, a new set of something that the majority of dsm'ers run, like Wiseco or Ross. If it works for everyone else, it should work for you. I know wisecos come with an anti-scuff skirt coating, if that's what you're looking for. To be safe you would need to re-check the piston to wall clearance when installing new pistons.
 
I dont imagine the discussion turn around why i melt the 2618, i only try to know if the alloy is not recomended for street and why. I realize then does not matter, docis of bad luck is involved in my case.

To do not get off the topic the conclusion can be: Does not matter the alloys? what is its use? they was created only for bussines reasons? to have a cheap alternative? the argument written on stone "both will melt, both will fail, is all about tunning and luck in your side" is a reasonable conclusion.
 
"both will melt, both will fail, is all about tunning and luck in your side" is a reasonable conclusion.

That would be fair to say. A good name replacement piston will melt either way. One or the other... They will melt. Get your motor back on track and FIND YOUR PROBLEM! I dont want to see you have this happen again.

Good luck to you! :thumb:

Jake
 
Right, they will both melt under those conditions.

The difference is 4032 has higher silicon content which gives it less thermal expansion. This makes it more street friendly since you can run slightly tighter piston to wall clearance and not have to worry about piston slap. Supposedly 4032 is more brittle than 2618, so when it's already driven to the edge and you add detonation, it might crack first.

I don't know how much power you're trying to make, but I wouldn't worry about it until you're well north of 500hp. Hell, people make more than that on stock pistons, which I believe are cast and have even higher silicone content than 4032 (don't quote me on that, but I'm ASSuming based on the tight piston to wall clearance they run at). Someone correct me if I'm wrong.
 
Once warmed up though, both types of material will have the same cylinder to piston clearance.
 
Your quest should not be for pistons at this point. Put a set of Ross (I preffer) or other name brand in there and fix your lean/ detonation problem. This is not a defective piston problem. The melted piston is a side affect of your other problem.

Good luck to you,

Jake
+1 and i like ross never had a problem with them
 
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