Posted By: funnycar65
Hypereutectic Pistons,yes or no - 11/09/14 04:42 PM
Whats everyones thoughts in a street/strip 4.15 stroke 440.I've heard some horror stories about them being prone to cracking.
Hypereutectic Pistons,yes or no
Posted By: Anonymous
Re: Hypereutectic Pistons,yes or no - 11/09/14 04:55 PM
There has never been a failure when correct installation and all that goes with that is followed.
Lots of KB"S --failed--but then all of those builders failed to follow correct ring gapping instructions, ran the engines with incorrect timing and experienced detonation etc
I have built over one hundred engines with all brands of Hyper pistons--they are great!! The KB's are DIFFERENT and are hard to machine valve pockets in etc and are of a more brittle alloy than any other brand but....forget the "key Jockey" fears--gap top ring exactly as they say--run the piston to wall on the fat side NOT the tight side and FEAR NOT. You show me a failure and I will show you an engine builder that said he knew better than the maker.
I think that in the world of 440 pistons it is just plain stupid to pay the going rate of around $450 for cheap cast pistons hyper or otherwise--You are much better off with a forged piston--the lighter the better--I mean skip the Speed Pro boat anchors unless....you are doing a simple street engine then it really makes little difference. Pistons are the one part that has climbed in price to the level of crazy but there is no way around it if you do a nice unit--you want a plain hyd cam street engine go with whatever--you want a 500 HP plus go with forged like Ross, JE, Diamond etc
Do Not fear the hypers--just follow the directions.
Lots of KB"S --failed--but then all of those builders failed to follow correct ring gapping instructions, ran the engines with incorrect timing and experienced detonation etc
I have built over one hundred engines with all brands of Hyper pistons--they are great!! The KB's are DIFFERENT and are hard to machine valve pockets in etc and are of a more brittle alloy than any other brand but....forget the "key Jockey" fears--gap top ring exactly as they say--run the piston to wall on the fat side NOT the tight side and FEAR NOT. You show me a failure and I will show you an engine builder that said he knew better than the maker.
I think that in the world of 440 pistons it is just plain stupid to pay the going rate of around $450 for cheap cast pistons hyper or otherwise--You are much better off with a forged piston--the lighter the better--I mean skip the Speed Pro boat anchors unless....you are doing a simple street engine then it really makes little difference. Pistons are the one part that has climbed in price to the level of crazy but there is no way around it if you do a nice unit--you want a plain hyd cam street engine go with whatever--you want a 500 HP plus go with forged like Ross, JE, Diamond etc
Do Not fear the hypers--just follow the directions.
Posted By: Challenger 1
Re: Hypereutectic Pistons,yes or no - 11/09/14 06:00 PM
I built a 340 with KB 243 hyper pistons in 2007. I used a stock bore block and honed it myself. I have driven the motor 26K miles so far and have driven the motor hard and long in Bonneville at 120 mph for miles at a time more than a dozen times. Driven it in 114° temps in Vegas and Reno several times and the motor has the same cranking compression today as when it was new. Nothing wrong with hyper pistons for the street. I wouldn't use them for nitrous or boost.
Posted By: Oyvind Mopar
Re: Hypereutectic Pistons,yes or no - 11/09/14 06:52 PM
I have had mixed experience. I will avoid the KB 280 pistons, as there is too little material between the top ring and the exhaust notch where the piston is at the hottest. I have had failure in an engine taking out the ring lands in the 4 center pistons. Tried to evaluate the issue and compared different KB hypers, and the 280 is unfortunately nothing I would recommend. I also see there are different designs on these within the same part number for the valve notches. The ones that are milled through have this issue. If all conditions are correct, they might survive. If something overheats or detonates, they can fail, and they do much faster than forged pistons. I did follow all installation instructions, but it did not matter much.
No such bad experiences with the KB LA hypers, they are also designed differently and have more metal above the top ring.
But, I have measured the skirts after some run time, and they seem to deflect in the bottom and give more piston slap. Look at them, there is almost no support there.
So, as an engine builder I cannot recommend them, especially as they have been way overpriced lately.
My
No such bad experiences with the KB LA hypers, they are also designed differently and have more metal above the top ring.
But, I have measured the skirts after some run time, and they seem to deflect in the bottom and give more piston slap. Look at them, there is almost no support there.
So, as an engine builder I cannot recommend them, especially as they have been way overpriced lately.
My
Posted By: lewtot184
Re: Hypereutectic Pistons,yes or no - 11/09/14 06:55 PM
Quote:having used kb184's twice and looking to do another build with them, i agree with this with one exception. these pistons don't expand like forged and don't need the extra clearance. i think the bad hype about them is directly related to the idiots who refuse to read the instructions and follow them and the engine machinist/builders who's sanctimonious egos don't know their rectum from a whole in the ground.
There has never been a failure when correct installation and all that goes with that is followed.
Lots of KB"S --failed--but then all of those builders failed to follow correct ring gapping instructions, ran the engines with incorrect timing and experienced detonation etc
I have built over one hundred engines with all brands of Hyper pistons--they are great!! The KB's are DIFFERENT and are hard to machine valve pockets in etc and are of a more brittle alloy than any other brand but....forget the "key Jockey" fears--gap top ring exactly as they say--run the piston to wall on the fat side NOT the tight side and FEAR NOT. You show me a failure and I will show you an engine builder that said he knew better than the maker.
I think that in the world of 440 pistons it is just plain stupid to pay the going rate of around $450 for cheap cast pistons hyper or otherwise--You are much better off with a forged piston--the lighter the better--I mean skip the Speed Pro boat anchors unless....you are doing a simple street engine then it really makes little difference. Pistons are the one part that has climbed in price to the level of crazy but there is no way around it if you do a nice unit--you want a plain hyd cam street engine go with whatever--you want a 500 HP plus go with forged like Ross, JE, Diamond etc
Do Not fear the hypers--just follow the directions.
Posted By: Bad340fish
Re: Hypereutectic Pistons,yes or no - 11/09/14 07:39 PM
I put lots of miles and lots of passes on some kb243s before one of the cracked all the way across the top down to the pin. They had been ridden hard though, I used to hold a grudge about it but they got abused day in and day out.
I currently run some kb107s in my 360. When the air is good it makes close to 500hp. It's been on 3 drag weeks as well. I paid $245 for the pistons and rings from summit! kind of hard to complain.
I currently run some kb107s in my 360. When the air is good it makes close to 500hp. It's been on 3 drag weeks as well. I paid $245 for the pistons and rings from summit! kind of hard to complain.
Posted By: ahy
Re: Hypereutectic Pistons,yes or no - 11/09/14 08:01 PM
I wouldn't be concerned about them in warm stock stroke engine... installed as advised and not on the ragged edge with high compression.
In a stroker, you have more power which makes more heat, shorter compression height, and most folks push the compression ratio. Forged can handle the stroker demands better.
In a stroker, you have more power which makes more heat, shorter compression height, and most folks push the compression ratio. Forged can handle the stroker demands better.
Posted By: Crizila
Re: Hypereutectic Pistons,yes or no - 11/09/14 08:03 PM
Quote:
There has never been a failure when correct installation and all that goes with that is followed.
Lots of KB"S --failed--but then all of those builders failed to follow correct ring gapping instructions, ran the engines with incorrect timing and experienced detonation etc
I have built over one hundred engines with all brands of Hyper pistons--they are great!! The KB's are DIFFERENT and are hard to machine valve pockets in etc and are of a more brittle alloy than any other brand but....forget the "key Jockey" fears--gap top ring exactly as they say--run the piston to wall on the fat side NOT the tight side and FEAR NOT. You show me a failure and I will show you an engine builder that said he knew better than the maker.
I think that in the world of 440 pistons it is just plain stupid to pay the going rate of around $450 for cheap cast pistons hyper or otherwise--You are much better off with a forged piston--the lighter the better--I mean skip the Speed Pro boat anchors unless....you are doing a simple street engine then it really makes little difference. Pistons are the one part that has climbed in price to the level of crazy but there is no way around it if you do a nice unit--you want a plain hyd cam street engine go with whatever--you want a 500 HP plus go with forged like Ross, JE, Diamond etc
Do Not fear the hypers--just follow the directions.
Posted By: Hot 340
Re: Hypereutectic Pistons,yes or no - 11/09/14 08:35 PM
Quote:
You show me a failure and I will show you an engine builder that said he knew better than the maker.
Worthy to be a sig quote.
Posted By: 383man
Re: Hypereutectic Pistons,yes or no - 11/09/14 10:44 PM
I have KB hypers in my old 440 that I built in 2005. It went on the road in 2006 and I pulled it in 2011 to put my stroker in and the 440 is still going strong in a Duster. I raced it and put alot of street miles on it and never a problem. Course I made sure I set the ring gaps as per instructions. Ron
Posted By: Anonymous
Re: Hypereutectic Pistons,yes or no - 11/10/14 04:27 AM
Quote:Quote:having used kb184's twice and looking to do another build with them, i agree with this with one exception. these pistons don't expand like forged and don't need the extra clearance. i think the bad hype about them is directly related to the idiots who refuse to read the instructions and follow them and the engine machinist/builders who's sanctimonious egos don't know their rectum from a whole in the ground.
There has never been a failure when correct installation and all that goes with that is followed.
Lots of KB"S --failed--but then all of those builders failed to follow correct ring gapping instructions, ran the engines with incorrect timing and experienced detonation etc
I have built over one hundred engines with all brands of Hyper pistons--they are great!! The KB's are DIFFERENT and are hard to machine valve pockets in etc and are of a more brittle alloy than any other brand but....forget the "key Jockey" fears--gap top ring exactly as they say--run the piston to wall on the fat side NOT the tight side and FEAR NOT. You show me a failure and I will show you an engine builder that said he knew better than the maker.
I think that in the world of 440 pistons it is just plain stupid to pay the going rate of around $450 for cheap cast pistons hyper or otherwise--You are much better off with a forged piston--the lighter the better--I mean skip the Speed Pro boat anchors unless....you are doing a simple street engine then it really makes little difference. Pistons are the one part that has climbed in price to the level of crazy but there is no way around it if you do a nice unit--you want a plain hyd cam street engine go with whatever--you want a 500 HP plus go with forged like Ross, JE, Diamond etc
Do Not fear the hypers--just follow the directions.
I see that KB usually says tight like couple thou--I usually add another thou or two nothing excess--they are not supposed to expand any but ...
And remember KB is the only brand of hyper that you do the bigger gap for due to the alloy they use--
Posted By: Bad340fish
Re: Hypereutectic Pistons,yes or no - 11/10/14 04:30 AM
Quote:
I see that KB usually says tight like couple thou--I usually add another thou or two nothing excess--they are not supposed to expand any but ...
And remember KB is the only brand of hyper that you do the bigger gap for due to the alloy they use--
I thought they moved the ring up some as well causing it to run hotter, thus needing the extra gap.
Posted By: NTOLERANCE
Re: Hypereutectic Pistons,yes or no - 11/10/14 05:56 AM
What's special about the ring gap procedure?
Posted By: Sport440
Re: Hypereutectic Pistons,yes or no - 11/10/14 06:19 AM
Quote:
What's special about the ring gap procedure?
The top ring gap is wider then other type pistons. They have a formula ring gap factor based on piston diameter vs engine useage, NA/Turbo/Nitrous ETC
Posted By: Cab_Burge
Re: Hypereutectic Pistons,yes or no - 11/10/14 09:43 AM
A cast piston will grenade into many small peices in the crankcase with small abuse, FOD or detonation, that a forged piston will survive 
Been there done that if your a excellent tuner and builder do what you want, if not take the safe route and go forged
Been there done that if your a excellent tuner and builder do what you want, if not take the safe route and go forged
Posted By: Oyvind Mopar
Re: Hypereutectic Pistons,yes or no - 11/10/14 10:16 AM
Quote:
A cast piston will grenade into many small peices in the crankcase with small abuse, FOD or detonation, that a forged piston will survive
I agree! Those 80 grams lighter than stock come at a price....Although I have built many engines using them as stock replacements. Great for the smallblocks, but the price increase on the others -> go forged
Posted By: slantzilla
Re: Hypereutectic Pistons,yes or no - 11/10/14 01:17 PM
I have sprayed a boatload of nitrous on KB pistons and have dameged a few when the tune-up was wrong. However, the same tune-up would have killed forged pistons too. I have never shattered one, but I did split one in half.
Posted By: RAMM
Re: Hypereutectic Pistons,yes or no - 11/10/14 02:58 PM
Quote:Quote:having used kb184's twice and looking to do another build with them, i agree with this with one exception. these pistons don't expand like forged and don't need the extra clearance. i think the bad hype about them is directly related to the idiots who refuse to read the instructions and follow them and the engine machinist/builders who's sanctimonious egos don't know their rectum from a whole in the ground.
There has never been a failure when correct installation and all that goes with that is followed.
Lots of KB"S --failed--but then all of those builders failed to follow correct ring gapping instructions, ran the engines with incorrect timing and experienced detonation etc
I have built over one hundred engines with all brands of Hyper pistons--they are great!! The KB's are DIFFERENT and are hard to machine valve pockets in etc and are of a more brittle alloy than any other brand but....forget the "key Jockey" fears--gap top ring exactly as they say--run the piston to wall on the fat side NOT the tight side and FEAR NOT. You show me a failure and I will show you an engine builder that said he knew better than the maker.
I think that in the world of 440 pistons it is just plain stupid to pay the going rate of around $450 for cheap cast pistons hyper or otherwise--You are much better off with a forged piston--the lighter the better--I mean skip the Speed Pro boat anchors unless....you are doing a simple street engine then it really makes little difference. Pistons are the one part that has climbed in price to the level of crazy but there is no way around it if you do a nice unit--you want a plain hyd cam street engine go with whatever--you want a 500 HP plus go with forged like Ross, JE, Diamond etc
Do Not fear the hypers--just follow the directions.
This ^^^^^^^ Run the extra clearance if you wish-but it will sound like a Volks diesel. J.Rob