Re: Hypereutectic Pistons,yes or no
[Re: funnycar65]
#1696477
11/09/14 12:55 PM
11/09/14 12:55 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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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. 
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Re: Hypereutectic Pistons,yes or no
[Re: ]
#1696479
11/09/14 02:52 PM
11/09/14 02:52 PM
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Joined: Jul 2009
Posts: 413
Norway (old world)
Oyvind Mopar
mopar
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mopar
Joined: Jul 2009
Posts: 413
Norway (old world)
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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
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Re: Hypereutectic Pistons,yes or no
[Re: ]
#1696480
11/09/14 02:55 PM
11/09/14 02:55 PM
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Joined: Jun 2008
Posts: 3,916
usa
lewtot184
master
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master
Joined: Jun 2008
Posts: 3,916
usa
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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.
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.
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Re: Hypereutectic Pistons,yes or no
[Re: lewtot184]
#1696481
11/09/14 03:39 PM
11/09/14 03:39 PM
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Joined: Jan 2003
Posts: 8,027
Tulsa OK
Bad340fish
master
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master
Joined: Jan 2003
Posts: 8,027
Tulsa OK
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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.
68 Barracuda Formula S 340
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Re: Hypereutectic Pistons,yes or no
[Re: ]
#1696484
11/09/14 04:35 PM
11/09/14 04:35 PM
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Joined: Dec 2006
Posts: 3,395
Pa
Hot 340
master
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master
Joined: Dec 2006
Posts: 3,395
Pa
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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. 
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Re: Hypereutectic Pistons,yes or no
[Re: lewtot184]
#1696486
11/10/14 12:27 AM
11/10/14 12:27 AM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
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.
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.
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--
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Re: Hypereutectic Pistons,yes or no
[Re: Bad340fish]
#1696488
11/10/14 01:56 AM
11/10/14 01:56 AM
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Joined: Aug 2003
Posts: 4,384
Madison Wi
NTOLERANCE
master
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master
Joined: Aug 2003
Posts: 4,384
Madison Wi
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What's special about the ring gap procedure?
I used to care but....... things have changed
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Re: Hypereutectic Pistons,yes or no
[Re: NTOLERANCE]
#1696489
11/10/14 02:19 AM
11/10/14 02:19 AM
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Joined: Jan 2003
Posts: 6,591
Canton, Ohio
Sport440
master
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master
Joined: Jan 2003
Posts: 6,591
Canton, Ohio
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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
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Re: Hypereutectic Pistons,yes or no
[Re: Cab_Burge]
#1696491
11/10/14 06:16 AM
11/10/14 06:16 AM
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Joined: Jul 2009
Posts: 413
Norway (old world)
Oyvind Mopar
mopar
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mopar
Joined: Jul 2009
Posts: 413
Norway (old world)
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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   Been there done that if your a excellent tuner and builder do what you want, if not take the safe route and go forged
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
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Re: Hypereutectic Pistons,yes or no
[Re: Oyvind Mopar]
#1696492
11/10/14 09:17 AM
11/10/14 09:17 AM
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Joined: Jan 2003
Posts: 20,179
Park Forest, IL
slantzilla
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 20,179
Park Forest, IL
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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.
"Everybody funny, now you funny too."
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