[jamaca85]

how do these pistons hold up vs forged and cast stock pistons? What brand is better if any?

[steve25]

How much hp are you looking to make?

[jamaca85]

not much around 500....no NOS I had a one fall apart on me years ago and just wondering if they gotten any better since then

[steve25]

They have not gotten any better so if your going to use them again your tuning skills need to improve and or apply less power to them.

Since you failed a motor with them I would assume you now see that once that costly misfortune takes place that in hindsight it’s better to go with forged pistons.

[mgarblik]

I don't like them and only use them if nothing else is available. They are so extremely brittle, just a small amount of trace detonation can crack them, break the ring lands and cause other engine damage. Think of them as pistons made of glass. Lower end 4032 forged pistons are a giant step up from hypereutectic pistons. 2618 forgings are the best of course but might make a little noise in a quiet street car. In the overall cost of building a new engine, a couple hundred bucks for forged pistons gives you a much larger tuning window, room to grow your power, and lets you sleep at night.
On a typical V-8, if 400-450 HP is the goal, I would use stock cast pistons vs hypereutectic if saving money was the goal. They are not an upgrade IMO.

I should mention piston to wall clearance if your going to try a set. Make sure your machinist pays close attention to the instructions with the hypereutectic pistons. They run very tight in the bores compared to forgings. Typically, .0025" is the absolute max for a 4.150 bore. They generally prefer .0015"-.002". If the machinist sets them up at the typical .004-.005 like a low end forging, they WILL crack or fail in some way. Running so tight in the bore, an excellent hone job is required, torque plates highly recommended. Max taper .0003". Max out of round .0003". An awful lot of precision, time and effort for little to no benefit.

[PAUL K]

Great pistons if you don't detonate the engine and pay attention to the ring gap instructions.

[jamaca85]

thanks guys I got my answer.. thanks for the input

[Iggy]

Chevrolet started using hypereutectic pistons in 1991 in the Gen V Big Block and followed in 1996 in the Vortec Small Blocks. I have used them in several mild Chevy builds with no issues. I followed the advice of a group of dirt track racers that use only hypereutectic pistons in their Claimer engines - follow the manufactures installation instructions, it the ring gap is too close the piston will break (they found out the hard way).

I will say that since I am now working on a Pontiac, for a few dollars more I can run a low grade forged in a mild build, that is the route I will go. What works in the Chevy world may not be the best in a Pontiac. But I am pretty sure if you followed the instruction on the ring gap it would be fine, but the additional cost to move up in minimal.

[mgarblik]

Originally Posted by Iggy

Chevrolet started using hypereutectic pistons in 1991 in the Gen V Big Block and followed in 1996 in the Vortec Small Blocks. I have used them in several mild Chevy builds with no issues. I followed the advice of a group of dirt track racers that use only hypereutectic pistons in their Claimer engines - follow the manufactures installation instructions, it the ring gap is too close the piston will break (they found out the hard way).

I will say that since I am now working on a Pontiac, for a few dollars more I can run a low grade forged in a mild build, that is the route I will go. What works in the Chevy world may not be the best in a Pontiac. But I am pretty sure if you followed the instruction on the ring gap it would be fine, but the additional cost to move up in minimal.

I have built several claimer SBC engines for friends running those classes. It's just incredible how cheap you can still buy pistons for. $100.00 will buy a set of 8 pistons and pins for those engines! You can't buy a set of dead, used Pontiac cast pistons for $100.00.

[Goatracer1]

I am not going to disagree with you guys because you are probably more knowledgeable than me. I just want to say that I have been running the same set of KB hypereutectic pistons in my supercharged 428 since 2001. I have made sure since the beginning that the engine does not run lean. I also have found that timing means very little to the engine. It always runs good and gets decent mileage so something must be right.