Magnum blocks, grade of the cast iron?
#2273708
03/21/17 03:22 PM
03/21/17 03:22 PM
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gregsdart
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The title pretty much says it. I got into an argument, sort of, over what they are made of. I quaoted Shepards comments in How to hop up Magnum motors. Shepard says they are made of the same high nickel material as the Hemi blocks?
Last edited by gregsdart; 03/21/17 03:24 PM.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Magnum blocks, grade of the cast iron?
[Re: gregsdart]
#2273887
03/21/17 08:29 PM
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HotRodDave
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You can definatly tell when you hit em with a grinder back to back. I have built a few strokers that need clearance and the magnums are certainly tougher.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Magnum blocks, grade of the cast iron?
[Re: gregsdart]
#2273941
03/21/17 09:50 PM
03/21/17 09:50 PM
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dizuster
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I can't say for sure, but I would bet big bucks that there is NO WAY two blocks cast 25 years apart have the same metallurgy.
Technology just moves too fast... Granted we're talking now in 2017, but for comparison sake we're not even using the same plastic resins we were 2-3 years ago at Chrysler, let alone 25 years later.
I do agree the magnum stuff is much better. Not sure if it's quality control of the castings, material, or designs... but they seem to be able to hold better power then the early stuff.
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Re: Magnum blocks, grade of the cast iron?
[Re: gregsdart]
#2274101
03/22/17 07:00 AM
03/22/17 07:00 AM
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jyrki
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They also have at least thinner decks and are more prone to crack form the head bolt holes when producing power
Plynouth VIP '67 TT IC EFI
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Re: Magnum blocks, grade of the cast iron?
[Re: gregsdart]
#2274233
03/22/17 02:18 PM
03/22/17 02:18 PM
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Porter67
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I just picked up my 73 360 block and the first thing the machinist said, dam that block is hard as hell.
I asked if it was harder then a magnum block and he said it made the diamond hone sing like the industrial blocks do and pulled the motor just as hard.
So he said in his opinion my block was harder then any mag block hes bored/honed.
So... But really I dont care either way, im going to use what I can/have.
But I do have a couple mag blocks this makes me think about.
Last edited by EV2Bird; 03/22/17 02:43 PM.
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Re: Magnum blocks, grade of the cast iron?
[Re: Porter67]
#2274326
03/22/17 04:45 PM
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HotRodDave
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I just picked up my 73 360 block and the first thing the machinist said, dam that block is hard as hell.
I asked if it was harder then a magnum block and he said it made the diamond hone sing like the industrial blocks do and pulled the motor just as hard.
So he said in his opinion my block was harder then any mag block hes bored/honed.
So... But really I dont care either way, im going to use what I can/have.
But I do have a couple mag blocks this makes me think about. Do this then if you have both, take a carbide grinder go grind on an un important part on both and see for yourself witch one is harder. I wrote a big post pointing out all the differences in the two but no one seems to care to read it they just keep swearing the early 360 block is the best because their grandpa said so years before the magnum block ever came out. The magnum bock also had more meat in the pan rails and main sadles anchoring the mains, probably a good idea for the guys insisting on running 4 bolt mains.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Magnum blocks, grade of the cast iron?
[Re: gregsdart]
#2274422
03/22/17 08:02 PM
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slammedR/T
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Magnum blocks get a bad rep they are very tough, I jknow this from my own racing
2000 Dakota R/T, 408 magnum, 727, Indy heads 1000cfm 4150 carb, 93 octane fuel. motor; 10.258 @ 132.78 200 shot; 9.262 @ 144.69 racemagnum
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Re: Magnum blocks, grade of the cast iron?
[Re: slammedR/T]
#2274432
03/22/17 08:14 PM
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MR_P_BODY
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Has anyone tested the Brinell hardness on any of these blocks.. I know they did at Chrysler but I dont know the numbers for any one year.. I always thought they were in the 150 range.. or do a rockwell C on them
Last edited by MR_P_BODY; 03/22/17 08:15 PM.
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Re: Magnum blocks, grade of the cast iron?
[Re: MR_P_BODY]
#2274982
03/23/17 08:04 PM
03/23/17 08:04 PM
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mr_340
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Has anyone tested the Brinell hardness on any of these blocks.. I know they did at Chrysler but I dont know the numbers for any one year.. I always thought they were in the 150 range.. or do a rockwell C on them 150 Brinell sounds kind of soft to me. I assume that they use an SAE grade of cast iron. This would be a G1800, around 20ksi tensile strength. My Hemi block (older MP block) is 185 Brinell. https://en.wikipedia.org/wiki/Gray_iron
Floyd Lippencott IV
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Re: Magnum blocks, grade of the cast iron?
[Re: gregsdart]
#2275073
03/23/17 11:18 PM
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ozymaxwedge
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Don't see the bonus in having a hard block, we all know that hard stuff cracks. Id prefer a soft Aluminium block. Could someone school me on this ?
1963 Plymouth Max Wedge 1971 Barracuda
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Re: Magnum blocks, grade of the cast iron?
[Re: ozymaxwedge]
#2275141
03/24/17 01:09 AM
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mr_340
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Don't see the bonus in having a hard block, we all know that hard stuff cracks. Id prefer a soft Aluminium block. Could someone school me on this ? In most ferrous metals, the harder it is the higher the tensile strength, and also the more brittle it becomes. There is a trade off to be made. For the hardness of cast irons, the link above gives a ratio of tensile strength to hardness. "In the automotive industry, the SAE International (SAE) standard SAE J431 is used to designate grades instead of classes. These grades are a measure of the tensile strength-to-Brinell hardness ratio.[2] The variation of the tensile modulus of elasticity of the various grades is a reflection of the percentage of graphite in the material as such material has neither strength nor stiffness and the space occupied by graphite acts like a void, thereby creating a spongy material."
Floyd Lippencott IV
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Re: Magnum blocks, grade of the cast iron?
[Re: gregsdart]
#2275143
03/24/17 01:16 AM
03/24/17 01:16 AM
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70Cuda383
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You really don't care about harness at all if you want to get 'engineer' about it.
Material that fractures shortly after its yield point has a very small plastic region. This type of material, we often think of as being hard or brittle when we use common terms. Like ceramic or glass. Material that you can continue to stress beyond its yield point before it fractures has a large plastic region, and we often think of these materials as soft or malleable.
But the bottom line is both materials were stressed beyond their yield point and have received some sort of permanent damage that will never go away. Either a crack, or the material has deformed. Both are bad for an engine.
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Re: Magnum blocks, grade of the cast iron?
[Re: 70Cuda383]
#2275158
03/24/17 01:35 AM
03/24/17 01:35 AM
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MR_P_BODY
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You really don't care about harness at all if you want to get 'engineer' about it.
Material that fractures shortly after its yield point has a very small plastic region. This type of material, we often think of as being hard or brittle when we use common terms. Like ceramic or glass. Material that you can continue to stress beyond its yield point before it fractures has a large plastic region, and we often think of these materials as soft or malleable.
But the bottom line is both materials were stressed beyond their yield point and have received some sort of permanent damage that will never go away. Either a crack, or the material has deformed. Both are bad for an engine. True but you want it strong/stiff enough so it doesnt distort and stay/yield.. it has to have enough nickel for strength Like everything.. there is a balance to all this stuff.. even for making iron EDIT Look back 70 years.. a iron block was LUCKY to last 70K.. now days they go 250K on miles and still dont have a ridge
Last edited by MR_P_BODY; 03/24/17 01:41 AM.
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Re: Magnum blocks, grade of the cast iron?
[Re: Porter67]
#2275178
03/24/17 02:00 AM
03/24/17 02:00 AM
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Dave ive read and watched most of your stuff concerning the mags, even to the point of running out the the shop and looking at a 318 mag pan rail when you mentioned it vs others.
I dont doubt it a bit, it is hard for me to accept "newer" is better, esp in the mag. world when costs are so important to the company.
I will do that after bit just for kicks.
Ive never ported or ground on magnum heads, are they harder as well?
I am open to anything, my 318 mag is ready to build and is a per mag roller and ive a 360 pre mag builder.
Hmmm does this apply since they are pre mag blocks? I also read Dave's stuff on the Magnum blocks and my next sm blk build will probably be based on a Mag block.
Fastest 300
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