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5.9 Magnum Pistons
#823808
10/06/10 10:47 PM
10/06/10 10:47 PM
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Joined: Aug 2007
Posts: 2,356
Kentucky
dfsmopars
OP
top fuel
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OP
top fuel
Joined: Aug 2007
Posts: 2,356
Kentucky
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I am finding out that finding pistons for the 5.9 Magnum I am building is more difficult than I intially thought. I talked to a tech. rep. at KB today who told me since I am truing up the deck and the heads (~0.020" total) this would cause me problems with the piston being above the deck and not enough quench area. He said their pistons are designed to be zero deck and that I'd end up spending a bunch of money on custom head gaskets.
Please help me out here I know this can't be this difficult.
‘72 Charger, 5.9 Magnum, Tremec 5 spd., Pro-Touring
‘14 Big Horn, Quad Cab, 4x4, 1500
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Re: 5.9 Magnum Pistons
[Re: dfsmopars]
#823809
10/06/10 10:52 PM
10/06/10 10:52 PM
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Joined: Apr 2010
Posts: 142
Maryland
Sick 660r
member
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member
Joined: Apr 2010
Posts: 142
Maryland
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My block was decked twice puting my pistons .015" out of the hole. Ended up going with thicker cometics.
Last edited by Sick 660r; 10/06/10 10:53 PM.
2000 dakota
418 magnum
paxton novi 2k
T56
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Re: 5.9 Magnum Pistons
[Re: dfsmopars]
#823811
10/06/10 11:18 PM
10/06/10 11:18 PM
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Joined: Apr 2010
Posts: 142
Maryland
Sick 660r
member
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member
Joined: Apr 2010
Posts: 142
Maryland
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4.040 bore and .060" thickness cost me 250 shipped.
2000 dakota
418 magnum
paxton novi 2k
T56
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Re: 5.9 Magnum Pistons
[Re: Sick 660r]
#823812
10/06/10 11:26 PM
10/06/10 11:26 PM
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Joined: Aug 2007
Posts: 2,356
Kentucky
dfsmopars
OP
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OP
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Joined: Aug 2007
Posts: 2,356
Kentucky
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That is crazy.  That is exactly what the KB guy told me to expect, or more. The 0.060" gasket is what he said I'd probably have to go with but he highly recommended mocking it up first with the pistons and crank assembled. Did you explore any other possibilities or were there none?
‘72 Charger, 5.9 Magnum, Tremec 5 spd., Pro-Touring
‘14 Big Horn, Quad Cab, 4x4, 1500
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Re: 5.9 Magnum Pistons
[Re: dfsmopars]
#823813
10/07/10 12:25 AM
10/07/10 12:25 AM
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Joined: Jan 2003
Posts: 7,131
Amarillo, Texas
BBR
master
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master
Joined: Jan 2003
Posts: 7,131
Amarillo, Texas
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What height is he decking the block to?
Drag Week 2011 - 77th place - DD
Drag Week 2012 - 2nd place SRBB N/A
Drag Week 2014 - Kapooya
RMRW 2018
RMRW 2020
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Re: 5.9 Magnum Pistons
[Re: dfsmopars]
#823815
10/07/10 12:40 AM
10/07/10 12:40 AM
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Joined: Jul 2010
Posts: 2,091
Delray beach, Florida
Performance Only
top fuel
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top fuel
Joined: Jul 2010
Posts: 2,091
Delray beach, Florida
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realistically, if your going to do the job right, your probably either going to spend a little more for a better piston that has the correct deck height or your going to pay for the gaskets to get the piston to head clearance you need. sometimes there's just no way around it.
personally i'd rather use the better piston. looking on the upside, at least the cometics are reuseable if the need ever arises.
machine shop owner and engine builder
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Re: 5.9 Magnum Pistons
[Re: dfsmopars]
#823818
10/07/10 09:01 AM
10/07/10 09:01 AM
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Joined: Aug 2007
Posts: 2,356
Kentucky
dfsmopars
OP
top fuel
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OP
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Joined: Aug 2007
Posts: 2,356
Kentucky
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Alright then. I appreciate all the great information. You know what they say, "It is what it is." I am looking at the KB362 piston which will be somewhere around 9.6:1 compression with the block decked somewhere around 0.010" This means the piston will be somewhere around 0.019" above deck.
‘72 Charger, 5.9 Magnum, Tremec 5 spd., Pro-Touring
‘14 Big Horn, Quad Cab, 4x4, 1500
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Re: 5.9 Magnum Pistons
[Re: TheOtherDodge]
#823820
10/07/10 01:14 PM
10/07/10 01:14 PM
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Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
HotRodDave
I Live Here
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I Live Here
Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
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I am building a motor right now with KB 107s and with no block milling or squareing at all are all between .008 and .009 above deck to start with. I ran them in a stock 360 LA block and they were about the same amount under the deck and very un even. Fel pro makes a .051 gasket and I am going to use those and some aluminum closed chamber heads for a nice quench distance. I think the number is 8553 and should work good till pistons are about .015 out the hole, depending on how tight you want your quench.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: 5.9 Magnum Pistons
[Re: HotRodDave]
#823821
10/07/10 05:26 PM
10/07/10 05:26 PM
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Joined: Aug 2007
Posts: 2,356
Kentucky
dfsmopars
OP
top fuel
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OP
top fuel
Joined: Aug 2007
Posts: 2,356
Kentucky
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Quote:
I am building a motor right now with KB 107s and with no block milling or squareing at all are all between .008 and .009 above deck to start with. I ran them in a stock 360 LA block and they were about the same amount under the deck and very un even. Fel pro makes a .051 gasket and I am going to use those and some aluminum closed chamber heads for a nice quench distance. I think the number is 8553 and should work good till pistons are about .015 out the hole, depending on how tight you want your quench.
That all sounds right to me. I will certainly not do anything until I mock up the pistons. With a factory piston at 9.1:1 compression ratio what would be wrong with going with a stock piston, .01 off the deck and .01 off the head? This I think would be in the ball park of 9.5:1 which for my application would be good. Am I off base here?
‘72 Charger, 5.9 Magnum, Tremec 5 spd., Pro-Touring
‘14 Big Horn, Quad Cab, 4x4, 1500
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Re: 5.9 Magnum Pistons
[Re: dfsmopars]
#823822
10/07/10 06:37 PM
10/07/10 06:37 PM
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Joined: Jan 2003
Posts: 7,131
Amarillo, Texas
BBR
master
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master
Joined: Jan 2003
Posts: 7,131
Amarillo, Texas
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SCE has thicker head gaskets. Not cheap, but not quite as spendy as a Cometic. http://www.scegaskets.com/
Drag Week 2011 - 77th place - DD
Drag Week 2012 - 2nd place SRBB N/A
Drag Week 2014 - Kapooya
RMRW 2018
RMRW 2020
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Re: 5.9 Magnum Pistons
[Re: dizuster]
#823824
10/07/10 08:54 PM
10/07/10 08:54 PM
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Joined: Dec 2009
Posts: 1,074
detroit, mi
POS Dakota
super stock
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super stock
Joined: Dec 2009
Posts: 1,074
detroit, mi
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Quote:
Depends on thickness, but the SCE's are still pretty pricy. Only the high end SCE Titans have fire rings in them. Everything else needs o-rings.
And they are NOT cheap.
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Re: 5.9 Magnum Pistons
[Re: dfsmopars]
#823826
10/07/10 10:05 PM
10/07/10 10:05 PM
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Joined: May 2004
Posts: 1,522
Ste-Sophie, Quebec, Canada
Wedgeman
pro stock
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pro stock
Joined: May 2004
Posts: 1,522
Ste-Sophie, Quebec, Canada
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Of course it will !!!
I am using a Magnum block with the 745 KB/Ic pistons, may be .15 out of the hole,....don't settle for anything less than cometic, you'll be saving money since they are re usable ...mine are .050 thick, 10.1:1 cr engine and using a 250/250* @.050 solid lifter cam, RHS iron heads
KB 745 for 408
KB 362 for 360
Grreat performance !
Dan
Last edited by Wedgeman; 10/07/10 10:09 PM.
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Re: 5.9 Magnum Pistons
[Re: dfsmopars]
#823827
10/07/10 10:13 PM
10/07/10 10:13 PM
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Joined: Feb 2005
Posts: 5,221
Branson, Mo.
joedust451
super gas
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super gas
Joined: Feb 2005
Posts: 5,221
Branson, Mo.
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Quote:
Somebody please tell me I am going to be really glad I built the Magnum instead of building my 318! Tell me that when I get this Magnum in my Charger I am going to be like a woman giving birth that soon all the pain will be erased by the joy!! 
You will be VERY happy with it, me & a buddy are running "stock" bottom end 360 magnums in are darts with nothing wild by any means, I'm running 12.5s, he just went 11.79, he got his engine from a junkyard, mine was from a rolled 95 truck, factory pistons/rings/bearings ect. He runs alittle more comp (thinner head gaskets & i think his heads are 62cc)/gear/cam/stall then me, both of us run small carbs, his car has the factory interior & bench seat.
You should have no problem getting 9.5.1 with a stock dished piston without decking, just run a thinner head gasket & mill .020" off the heads, if you do deck the block, i'd say 10.1 shouldn't be hard to acheive, but i'd go with 9.5.1 so it will be pump gas friendly, i run on 87 octane.
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