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Formulation of AMC cast iron |
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farna
Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19676 |
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Modern carbide tools cut through any metal easily. It's the older tool steel bits that don't last as long on AMC blocks. Guys, I'm not digging through my paperwork right now, though I know you want to see something in writing. Somewhere I've got a statement that AMC used about 0.05% more nickel in their blocks. That's not much, but just enough to make it a bit tougher and harder. They did use the same mix in all the blocks and heads. It was this slightly tougher mix that allowed them to induction harden their heads instead of installing stellite seats when unleaded fuel became the norm. Otherwise the hardening would have made the seats too brittle. As someone pointed out to me -- it's just a case hardening that is only a few thousandths of an inch thick, so after maybe one valve seat grind it's pretty much gone (assuming the seats weren't damaged on that one grind!). I've had several old time machinists say they had to slow their boring down a bit to bore AMC blocks -- even old 196s (the first one who mentioned it was boring a 196 L-head for me back in 1980).
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Frank Swygert
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billd
Moderator Group Forum Administrator Joined: Jun/27/2007 Location: Iowa Status: Offline Points: 30894 |
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I worked with 2 machine shops here as well as a machine shop in my home town (the fellow son happened to be my HS metal shop teacher!)
I have asked - especially the one local shop that did my last 2 AMC blocks. I asked them as they have a wall full photos of vehicles with AMC engines they have done, they have a long history with Jeeps. They got this look like what the heck was I talking about....... no, they said they could never tell any difference. You can find reference on the web to Ford racing engines and some here and there about Chevy racing engines. Apparently it's confirmed that certain Ford engines did up the nickle content, but not across the board for all production engines. I have yet to find any shop that will even say "we think so" on AMC engines being "different" or harder. Even the shop that cut the 390 for me to install sleeves..... "not a problem, it's just like any other block we do" (I asked as at that time I, too, was questioning the content of those blocks.) And I'm talking about the old-timers my age or older, not youngsters in newer shops with modern equipment and tools. Some of their tooling is as old as I am. I've bored a few AMC 6s myself back in the 70s, using the Kent-Moore tools we had from when it was a dealership. I never noted any differences or difficulties. These tools I refer to came out of the late 50s. I have piston pin reamers and other dealer tools and equipment for working on those old engines - never a problem. I've run ridge-reamers through over the decades, including "cheap" ones and they cut the AMC block material just like any other block. (gotta be careful with those things or you can screw up a block as easily as saving it) |
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WARBED
Supporter of TheAMCForum Joined: Feb/12/2011 Location: Edinburg TX Status: Offline Points: 1683 |
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Whatever there made of they do hold up well.
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59 American 2dr S/W. 70 390 AMX. 70 232 javelin. Kelvinator fridge ice cold beer storage.
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Aljav
AMC Addicted Joined: Jul/18/2007 Location: Wisconsin Status: Offline Points: 1037 |
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We need to find someone who has other motors information. It be a good start for comparison and then we need to find someone who can tell us how to accurately compare the info.
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69 AMX 9.86 132 mph 71 JAV/AMX and 69 Javelin, .. NAMDRA member #1106
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centash
AMC Apprentice Joined: Oct/28/2012 Location: SW Ontario Status: Offline Points: 47 |
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could one apply Archemedies principle and immerse/weigh various blocks or heads to determine their density? Different densities of a Gm block vs. an AMC block would seem to infer different composition of the casting metals used. Anyone got a big tub....?
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Boris Badanov
AMC Addicted Joined: Dec/14/2013 Location: NH USA Status: Offline Points: 4209 |
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Cool idea, but the subtle differences from differing metalurgy and heat treat
anneal and use of chill blocks would be impossible to pick up by measuring volume/density in a tub of water More likely addition of different metal alloys and silica have to do with cracking/loss of castings at the foundry and initial machining operations. Maganese in tiny ammounts make the material tough, nickle seems to have been added primarily reducing cracking loss. If you want a hard surface in a casting iron, it's easy, just cool the area faster than the rest of the casting. In the bad old days they used "chill blocks" to harden the ways when manufacturing machienery. Boris Badanov
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Gremlin Dreams
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centash
AMC Apprentice Joined: Oct/28/2012 Location: SW Ontario Status: Offline Points: 47 |
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Guess I was just having an "Eureka!" moment....lol
Ben
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flyamerican
Supporter of TheAMCForum Joined: Nov/18/2009 Location: Sparks, Nevada Status: Offline Points: 28 |
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What you're doing is just the kind of data I'd like to see. I've heard that different castings of the same block can vary in hardness/tensile strength due to many factors. The only way to get solid info would be to send samples from many blocks to be tested, but I'm not suggesting you or anyone do this. Even checking one will maybe give you a real-life representation of the differences. Thanks!
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1970 Javelin SST 360
1985 Eagle wagon, 5-speed |
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White70JavelinSST
Supporter of TheAMCForum Joined: Aug/08/2012 Location: Minnesota Status: Offline Points: 4867 |
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Bringing this one back to the forefront too.
At 90 some thousand miles, the engine in the White70JavelinSST began to have a strange intermittent HUFF sound at the tail pipe. We decided it had ingested a bit of something or a chunk of carbon came loose and damaged at least one exhaust valve face and seat. Upon tear down, the cross hatch pattern was clearly visible in all the cylinder bores. I cannot explain why this was so except that the block was harder than the typical SBC which at about 90,000 the cylinders were pretty hogged out by the rings. Extra nickel in the cast iron? Who's to say? But this engine is harder than SBC material for sure. BTW we did this with the engine still in the car. blankin heads and intake are very heavy and a bear cat to lift out from the engine compartment. Armand |
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70 Javelin SST, second owner, purchased 1972
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WARBED
Supporter of TheAMCForum Joined: Feb/12/2011 Location: Edinburg TX Status: Offline Points: 1683 |
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I've had many engines machined and have used the same machinist on all my engines. He mentioned to me years ago that AMC, International and some chevy performance blocks were harder on his boring bar bits then other engines. he did mention nickle and the grade of iron in the blocks. It doesn't take much nickle to make a better formula for casting, too much and then you have concerns with heat dissapation and other concerns. oh and it gets real expensive.
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59 American 2dr S/W. 70 390 AMX. 70 232 javelin. Kelvinator fridge ice cold beer storage.
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