Hypereutectic Pistons

[jasonjb75]

I am starting to get the 383 out of the Charger (thanks to the bad head gasket and piston with missing pieces )  I started to compile a list of parts I want to get, especially with Carlisle coming up so soon.  A friend of mine told me to stay away from hypereutectic piston.  Anyone else have any reasons for this or suggest a piston I should be leaning too.  It is going to be built for street use, nothing crazy about the rebuild.

Thanks,

Jason

[no318]

There are 3 primary "types" of piston material  1-Stock cast 2-cast hypereutectic alloy 3-Forged.  There strength increases with each step.  So does cost and typically weight.  I personally like Hypereutectic pistons for street motors (if no forced induction, nitrous or extreme compression ratio).  The only down side is that they don't like detonation.  Detonation is hard on any engine.  Avoid it and you will be fine.  Typically they are cheaper and lighter weight than forged.  Also, there are more options out there.   

[jasonjb75]

I am guessing that the detonation is what did my current piston in or maybe in addition to the head gasket.  The head gasket was cooked between the #6 and #4 cylinder and the #6 cylinder is the piston that has the damage.  It has missing pieces of the skirt and a crap up the side if it to the wrist pin.  No matter what I did with the timing I couldn't get it to stop.

Thanks for the info on the pistons.  I needed the help to make sure I got something that would work well for my rebuild.

Jason

[my73charger]

I have a friend that had them in his 440 and he had one come apart on him while racing.  It destroyed his block when it came apart.  I would personally spend a little more and buy a forged piston.

[Cooter]

While the Hypereutectic pistons have gotten a bad rep with users, the main thing to remember when running them is to set the proper ring gaps...They now include a Big Red warning inside the box ..There is a ring gap for Nitrous, Alcohol, blower, etc...


I don't run them, but have a friend that has beaten the hell outta a set and had no problems. i would also reccomend the forged slug as well..

[b5blue]

I'm running Speed Pro Hyper's (9.5 to 1) in my 440 for the last 2 years with no issues on a daily driver. I don't beat the beans out of my engine though. I was going to go forged but they need to be looser in the bore's and with a daily driver's stop and go I figured the tighter build would be better as I'm not racing.

[bull]

You aren't going to find anyone who stocks a forged 383 piston. Everyone lists them but nobody actually sells them, especially the SpeedPros (ask Tufcat). If you want a forged piston -- which I also recommend you use instead of hypereutectic -- you'll probably have to get them from a custom builder like Diamond Racing.

[maxwellwedge]

I always go with forged - they are tougher and I can spell it! 

[no318]

I agree that forged is best for racing engines, nitrous, high compression, or forced induction.  I am just saying that they are not necessary for most street car builds on limited use vehicles. 

[Runner]

5 years on this set and i havent been nice to them.   set them up right and use them for thier intended purpose and you will be fine.    yup forged would be better but i couldnt find a shelfed forged piston that fit what i needed when i built mine. plus cost was afactor for me. 

http://www.youtube.com/watch?v=Imva1OaTUjY

[b5blue]

Ether Mopar Action or Mopar Muscle did a Tech. article on pistons that covered the pros and cons. 

[bull]

Ether Mopar Action or Mopar Muscle did a Tech. article on pistons that covered the pros and cons. 

And?

[b5blue]

Sorry.....basically we all know stock pistons held up fairly well for all the beatings they took for years but they were a compromise between cost, service life and general use. Forged were purpose built for being flogged like a red headed stepchild with no consideration for stop and go manners as they need a looser bore due to the rate they expand is greater. That translated into issues on cold start and temp extremes (like when it's really really cold and you jump in run to the store for a wile jump back in and go home) the piston is spending all that time expanding and contracting and very little at it's optimum fit in the bore. So forged like to be warmed up and then run best. Hyper's are a mix of the 2 due to a bunch of metallurgic mumbo jumbo I can't quote or claim to fully explain, they are manufactured in a way that forces more (the "hyper") of the whatever (the "eutectic") into the aluminum alloy to produce a piston that is stronger than stock but more expansion stable than forged. Being "harder" then both they are coated with a layer of "something" (bla bla bla) and yes exact boring of cylinder walls for maximum life and performance is different and critical. (to us it is no matter what we use I'm sure) The story was clear in that if your gonna beat the crap out of you engine 24/7, use ANY NOS or blower, Go FORGED! Live with the little puff of smoke and rattle you may get from cold start's loose bore. If your just putting around driving like a sane normal person (yea right) just go stock and save big $$$. In between the 2 extremes is a 3rd choice that was not available 40 years ago. Hooray for science (and beer!) Test on Friday...so study...I was hoping someone could dig up a link for you guys! (Keep in mind I'm paraphrasing something I read 3 years ago, not debating anyone's choice.)   

[RD]

i put a set of KB's in my 400 in 2004.  The engine still runs great to this day.  I have beat the hell out of it, but it works great still (though with a new owner now).

I had my rings fitted to pistons, so no gap issues.  They are good pistons and somewhat affordable in relation to everything.  Are they the best piston? Nope.  But, for those on a limited budget who need a street driver, they will work just fine without any issues (all being equal that is).

[RallyeMike]

i put a set of KB's in my 400 in 2004.  The engine still runs great to this day.  I have beat the hell out of it, but it works great still (though with a new owner now).

I had my rings fitted to pistons, so no gap issues.  They are good pistons and somewhat affordable in relation to everything.  Are they the best piston? Nope.  But, for those on a limited budget who need a street driver, they will work just fine without any issues (all being equal that is).

I'll 2nd that. Everything cannot always be the absolute best - most of us have to make choices where quality & toughness cross with cost and availability. Piston choices are very limited for 383 unless you want to pay for custom stuff. I run the KB hyper's in my race car and they have been fine. They happen to have the features I wanted and are reasonably priced, and if you want to talk about being tested for durability, what I am doing to them is probably about as extreme as anyone.

[RD]

i put a set of KB's in my 400 in 2004.  The engine still runs great to this day.  I have beat the hell out of it, but it works great still (though with a new owner now).

I had my rings fitted to pistons, so no gap issues.  They are good pistons and somewhat affordable in relation to everything.  Are they the best piston? Nope.  But, for those on a limited budget who need a street driver, they will work just fine without any issues (all being equal that is).

I'll 2nd that. Everything cannot always be the absolute best - most of us have to make choices where quality & toughness cross with cost and availability. Piston choices are very limited for 383 unless you want to pay for custom stuff. I run the KB hyper's in my race car and they have been fine. They happen to have the features I wanted and are reasonably priced, and if you want to talk about being tested for durability, what I am doing to them is probably about as extreme as anyone.

2ND THAT!!! And I thought I beat the crap out of mine hehehe!