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Re: Hypereutectic Pistons
[Re: MoparMuscle]
#436312
08/13/09 12:07 AM
08/13/09 12:07 AM
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Joined: Jan 2003
Posts: 27,421
Balt. Md
383man
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,421
Balt. Md
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I have them in my 63's mild 440 and my sons 400. Both are street cars that get street driven much more then raced. The Dart's 400 has been together since 2004 and my 63's 440 has been on the road since Sept 2006. I drive my 63 alot and have raced it about 6 times in the last 3 years as I go to a T & T 2 or 3 times a year. But we run them hard and the KB Hyper pistons are holding up fine. My son shifts his short stroke 400 at 6700 to 6800 and I shift my .030 over 440 (446) at 6200. You just have to be sure and set the piston to wall clearance and the ring end gaps as they tell you. The top ring is very important to set it as they tell you. They can have some piston slap noise when cold but it goes right away as it warms up. My son and I are also on tight budgets and thats why we used them also. My 440 uses 906 heads and the MP .557 cam and has run 11.50's so far. My boys Dart has hit 11.40's in good air. Any way we have had great results with the Hyper pistons and my brother also uses them in some of his race cars and none have had any piston trouble. Ron
Last edited by 383man; 08/13/09 12:08 AM.
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Re: Hypereutectic Pistons
[Re: qwkmopardan]
#436317
08/13/09 07:18 AM
08/13/09 07:18 AM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 12,675
Columbia, CT
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The issue I see is the piston to wall clearance has to be tighter than the factory cast pistons. With any hyper this is so. So .001" wear already makes the bores too large IMO. Read the post about bulging up valley pans with regard to ring sealing. Hypers are installed tight because they dont expand. Put them in loose and they may be noisey, they will not allow the rings to seal as well, and they might end up rocking over time and hurting the skirts. If this is a "for the time being" I'd simply run what you have (stock, or upgrade and have it bored for proper fitting hypers... Then when you tear it down again, you can simply hone it to the proper clearance for the good forged units.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: Hypereutectic Pistons
[Re: moper]
#436320
08/13/09 08:12 AM
08/13/09 08:12 AM
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Joined: Jan 2003
Posts: 302
Northeast Texas
MoparMuscle
OP
enthusiast
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OP
enthusiast
Joined: Jan 2003
Posts: 302
Northeast Texas
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Quote:
The issue I see is the piston to wall clearance has to be tighter than the factory cast pistons. With any hyper this is so. So .001" wear already makes the bores too large IMO. Read the post about bulging up valley pans with regard to ring sealing. Hypers are installed tight because they dont expand. Put them in loose and they may be noisey, they will not allow the rings to seal as well, and they might end up rocking over time and hurting the skirts. If this is a "for the time being" I'd simply run what you have (stock, or upgrade and have it bored for proper fitting hypers... Then when you tear it down again, you can simply hone it to the proper clearance for the good forged units.
The clearance was one of my concerns but after looking at the chart on their site it states .0020" - .0045" for bores over 4.100 in an na drag application with a top ring gap factor of .0075. It should be no problem to set it up in the middle at .003. 
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Re: Hypereutectic Pistons
[Re: Crizila]
#436321
08/13/09 08:16 AM
08/13/09 08:16 AM
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Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Too Many Posts
Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
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buddy of mine in the AF had one explode inside his small block chevy, he blamed it on the machine shop for setting the ring gaps improperly.
whats funny is this is the same machine shop that told me "you don't want to build a big block mopar stroker for your first engine...go build a SBC. you CAN'T screw those up
**Photobucket sucks**
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Re: Hypereutectic Pistons
[Re: MoparMuscle]
#436322
08/13/09 08:50 AM
08/13/09 08:50 AM
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Joined: Jan 2003
Posts: 75,004
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,004
U.S.S.A.
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Quote:
Quote:
The issue I see is the piston to wall clearance has to be tighter than the factory cast pistons. With any hyper this is so. So .001" wear already makes the bores too large IMO. Read the post about bulging up valley pans with regard to ring sealing. Hypers are installed tight because they dont expand. Put them in loose and they may be noisey, they will not allow the rings to seal as well, and they might end up rocking over time and hurting the skirts. If this is a "for the time being" I'd simply run what you have (stock, or upgrade and have it bored for proper fitting hypers... Then when you tear it down again, you can simply hone it to the proper clearance for the good forged units.
The clearance was one of my concerns but after looking at the chart on their site it states .0020" - .0045" for bores over 4.100 in an na drag application with a top ring gap factor of .0075. It should be no problem to set it up in the middle at .003.
Are you are assuming the bore you have now is on the TIGHT side ?
I personally don't have any use for a Hyper piston other than an ASH TRAY and I don't SMOKE  ..
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Re: Hypereutectic Pistons
[Re: mayhem148]
#436323
08/13/09 08:51 AM
08/13/09 08:51 AM
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Joined: Jul 2007
Posts: 863
Pinelands , NJ
joelson6
super stock
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super stock
Joined: Jul 2007
Posts: 863
Pinelands , NJ
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Quote:
but as everything else in this world they have there ups and downs.
a piston that has it's ups and downs, now that's funny
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Re: Hypereutectic Pistons
[Re: JohnRR]
#436324
08/13/09 10:03 AM
08/13/09 10:03 AM
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Joined: Jan 2003
Posts: 302
Northeast Texas
MoparMuscle
OP
enthusiast
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OP
enthusiast
Joined: Jan 2003
Posts: 302
Northeast Texas
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Quote:
Quote:
Quote:
The issue I see is the piston to wall clearance has to be tighter than the factory cast pistons. With any hyper this is so. So .001" wear already makes the bores too large IMO. Read the post about bulging up valley pans with regard to ring sealing. Hypers are installed tight because they dont expand. Put them in loose and they may be noisey, they will not allow the rings to seal as well, and they might end up rocking over time and hurting the skirts. If this is a "for the time being" I'd simply run what you have (stock, or upgrade and have it bored for proper fitting hypers... Then when you tear it down again, you can simply hone it to the proper clearance for the good forged units.
The clearance was one of my concerns but after looking at the chart on their site it states .0020" - .0045" for bores over 4.100 in an na drag application with a top ring gap factor of .0075. It should be no problem to set it up in the middle at .003.
Are you are assuming the bore you have now is on the TIGHT side ?
I personally don't have any use for a Hyper piston other than an ASH TRAY and I don't SMOKE ..
Not assuming, machinist miked with a dial bore gauge and the worst measurement was at the top of one cylinder and it was 4.3215.
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Re: Hypereutectic Pistons
[Re: W2DODGE]
#436326
08/13/09 10:40 AM
08/13/09 10:40 AM
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Joined: Oct 2003
Posts: 7,506
Az
Crizila
master
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master
Joined: Oct 2003
Posts: 7,506
Az
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Two things you gotta watch out for with hyper pistons - ring end gap and detonation. You wanna be sure you have enough octane rating to support your compression ratio / compression pressure and a fuel system that will deliver enough fuel at all times.
Fastest 300
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Re: Hypereutectic Pistons
[Re: MoparMuscle]
#436327
08/13/09 01:10 PM
08/13/09 01:10 PM
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Joined: Jan 2003
Posts: 75,004
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,004
U.S.S.A.
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Quote:
Quote:
Quote:
Quote:
The issue I see is the piston to wall clearance has to be tighter than the factory cast pistons. With any hyper this is so. So .001" wear already makes the bores too large IMO. Read the post about bulging up valley pans with regard to ring sealing. Hypers are installed tight because they dont expand. Put them in loose and they may be noisey, they will not allow the rings to seal as well, and they might end up rocking over time and hurting the skirts. If this is a "for the time being" I'd simply run what you have (stock, or upgrade and have it bored for proper fitting hypers... Then when you tear it down again, you can simply hone it to the proper clearance for the good forged units.
The clearance was one of my concerns but after looking at the chart on their site it states .0020" - .0045" for bores over 4.100 in an na drag application with a top ring gap factor of .0075. It should be no problem to set it up in the middle at .003.
Are you are assuming the bore you have now is on the TIGHT side ?
I personally don't have any use for a Hyper piston other than an ASH TRAY and I don't SMOKE ..
Not assuming, machinist miked with a dial bore gauge and the worst measurement was at the top of one cylinder and it was 4.3215.
Did he do this with a torque plate installed ? How many miles on this block ?
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Re: Hypereutectic Pistons
[Re: JohnRR]
#436328
08/13/09 02:14 PM
08/13/09 02:14 PM
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Joined: Jan 2003
Posts: 302
Northeast Texas
MoparMuscle
OP
enthusiast
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OP
enthusiast
Joined: Jan 2003
Posts: 302
Northeast Texas
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Quote:
Quote:
Quote:
Quote:
Quote:
The issue I see is the piston to wall clearance has to be tighter than the factory cast pistons. With any hyper this is so. So .001" wear already makes the bores too large IMO. Read the post about bulging up valley pans with regard to ring sealing. Hypers are installed tight because they dont expand. Put them in loose and they may be noisey, they will not allow the rings to seal as well, and they might end up rocking over time and hurting the skirts. If this is a "for the time being" I'd simply run what you have (stock, or upgrade and have it bored for proper fitting hypers... Then when you tear it down again, you can simply hone it to the proper clearance for the good forged units.
The clearance was one of my concerns but after looking at the chart on their site it states .0020" - .0045" for bores over 4.100 in an na drag application with a top ring gap factor of .0075. It should be no problem to set it up in the middle at .003.
Are you are assuming the bore you have now is on the TIGHT side ?
I personally don't have any use for a Hyper piston other than an ASH TRAY and I don't SMOKE ..
Not assuming, machinist miked with a dial bore gauge and the worst measurement was at the top of one cylinder and it was 4.3215.
Did he do this with a torque plate installed ? How many miles on this block ?
Didn't use a torque plate to mike it but he will when honing. The motor came out of a small motorhome that only had 30000 miles on it. Bearings, cam lobes, pistons all looked immaculate very very clean inside. I was almost tempted to reuse the bearings they looked so good.
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Re: Hypereutectic Pistons
[Re: MoparMuscle]
#436329
08/13/09 05:28 PM
08/13/09 05:28 PM
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Joined: Jan 2005
Posts: 3,635
Oakland, MI
dizuster
master
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master
Joined: Jan 2005
Posts: 3,635
Oakland, MI
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I think the thing people often misunderstand about piston clearance, is that pistons are designed and machined undersized for a given bore. If you have a 4" bore. The piston doesn't come in at 4" and you bore/hone for .005 of clearance. The piston is designed and machined to come in at 3.995" to give you .005" of clearance in a 4" bore. So just because an old block used pistons with a ton of clearance, doesn't mean that you can't put a hypereutectic in it. If the bore is only over .001", it will only ad point .001" into the new piston clearance regardless of what brand/type of piston that was in the motor. Of course pistons need to be checked for size, but machining and quality is so good now, you don't really have to worry about it. I built a 340 with hypereutectic pistons in it a LONG time ago. It's got 500~600 passes, and God knows how many street miles on it. I'd use them again for a street/strip build in a heartbeat.
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with all the above. To be on the safe side, I run the ring end gap about .002" larger than recommended ( top ring ). Although they recommend a tight piston to wall clearance,.002 - .003" will be ok. Minor spray ( 125 shot ) will be ok also.
