Block Hardness Testing

[mbrunson427]

I watched a deal today where a guy was doing an "engine block shootout", testing a bunch of different variations of Nissan engine blocks to show which one of the factory blocks was probably best to scoop up if preparing for a performance build. He was using a sonic tester, but also a hardness tester. Sonic testing is fairly common but I had never seen hardness testing done in this fashion before.

It got me wondering if anyone has done such a thing with FE blocks. I'm sure someone has, I just haven't run into it yet. Makes me curious if there is a significant variation of hardness in FE castings or if there are any patterns that develop year to rear, plant to plant, by engine size, etc.

Another curiosity of mine is whether or not more hardness is really better. In the video I watched, the guy basically made a blanket conclusion that the larger the cylinder wall thickness and the harder the block, the better. Harder materials are often more brittle though......

This is the video I'm referring to. In case anybody nerds out (like me) hard enough to watch a video about Nissan inline 6 engines.
https://www.youtube.com/watch?v=KF1iTh-2u3E

[machoneman]

"Makes me curious if there is a significant variation of hardness in FE castings or if there are any patterns that develop year to rear, plant to plant, by engine size, etc."

I would be very surprised to see any large variation even across various foundries and time (FE's years of production). Having some knowledge of GM's old Central Foundry Division's operations (sorry, no FoMoCo background) they did carefully choose their iron used to be melted and poured. Even with some variations in the mix of metals used, I'm not sure that hardness varied much of at all.   

I do know that casting irregularities were a major issue (short shots, shifted molds, damaged core boxes, unexpected pinholes and a raft of other issue) for all the plants. Oddly, I was told that bad runs were simply crushed and thrown back into the pile for re-melting. Q.C. back then was badly missing and all the casting operations were terrible places to work in, hence poor operations lead to lots of rejects.   

[Falcon67]

The harder the material, the harder it would be to machine. 

https://www.azahner.com/resources/metal-hardness

[fekbmax]

Ahh, brings back memories of all the tails of there being a high nickel FE block.
Not sure if this has ever been proven one way or the other.

[e philpott]

I know people that check hardness of Sleeves but never anybody check a iron block though probably not a bad idea

[RJP]

I know people that check hardness of Sleeves but never anybody check a iron block though probably not a bad idea

Not true, Several years ago I witnessed a Rockwell hardness testing on a pair of Dodge Pro Stock blocks at a machine shop in the central valley, Ca. for Panella Racing. Each block was tested on several locations of each block checking for casting uniformity and hardness consistency. Each probe was done on various non machined areas of the castings. This was done to confirm that the castings were exactly what they were paying for correct CGI material. Panella had done the sonic testing prior to hardness testing. And given the competitive nature of Pro Stock racing if one is doing it then most likely all of them are doing it.   

[Falcon67]

Having been a QA guy in the past, I'd assume Ford QA would have test sampled block as part of the determination that the iron was being formulated to engineering specs.  Other than that, probably not. 

Adding nickel to the casting would just make them harder to machine, require more expensive tooling and such.  Not likely a common thing that would be introduced on a production line, more like one off special runs handled elsewhere.  If I had a nickel for every time I'v read about high nickle blocks on the web...

[thatdarncat]

Ahh, brings back memories of all the tails of there being a high nickel FE block.
Not sure if this has ever been proven one way or the other.

The subject continually comes up on the FE Facebook page, thankfully with the help of Dennis K. who worked at Ford and has researched the subject and checked the engineering specs it’s been proven to be false in the case of FE production blocks, including 427’s. This includes all the old stories of the “X” on certain blocks signifying high nickel, etc. And yet probably a week doesn’t go by where someone doesn’t chime in with some convoluted story of how they know it’s true. Here’s this weeks answer from Dennis regarding the question:

[mbrunson427]

Most of the above responses are citing the material composition. I have no doubt that Ford had a pretty tight hold on that. The variable I wonder about is faster/slower cooling after leaving the mold or longer time being set in the mold. Just makes you wonder is all. Not that many of us, or any at all, would change our opinion of an FE block that we had because a hardness test showed that it was less than the average FE block.

[e philpott]

I know people that check hardness of Sleeves but never anybody check a iron block though probably not a bad idea

Not true, Several years ago I witnessed a Rockwell hardness testing on a pair of Dodge Pro Stock blocks at a machine shop in the central valley, Ca. for Panella Racing. Each block was tested on several locations of each block checking for casting uniformity and hardness consistency. Each probe was done on various non machined areas of the castings. This was done to confirm that the castings were exactly what they were paying for correct CGI material. Panella had done the sonic testing prior to hardness testing. And given the competitive nature of Pro Stock racing if one is doing it then most likely all of them are doing it.   

I believe it for sure for sure , someone has to know block hardness from the factory , I just don't know of anybody personally that tested a block but know several people that has tested sleeves

[Machspeed]

I haven't watched the video yet but we use these in our shop to quickly check hardness depending on the application.

https://www.mscdirect.com/browse/tnpla/06534309?cid=ppc-google-New+-+Measuring+%26+Inspecting+-+PLA_sMqjfrUFc___164110844328_c_S&mkwid=sMqjfrUFc|dc&pcrid=164110844328&rd=k&product_id=06534309&gclid=EAIaIQobChMI1u34oZKJ3wIViFYNCh1kxgOqEAQYASABEgLX8fD_BwE


I've never thought about checking a factory block.

[6667fan]

I could not view Dennis’s response. I thought that the final iteration of 427s after early May ‘72 included more phosphorus in the blocks. Perhaps that would increase hardness and I assume the reason for the “P” on the rear bulkhead.
JB

[cammerfe]

I know people that check hardness of Sleeves but never anybody check a iron block though probably not a bad idea

Not true, Several years ago I witnessed a Rockwell hardness testing on a pair of Dodge Pro Stock blocks at a machine shop in the central valley, Ca. for Panella Racing. Each block was tested on several locations of each block checking for casting uniformity and hardness consistency. Each probe was done on various non machined areas of the castings. This was done to confirm that the castings were exactly what they were paying for correct CGI material. Panella had done the sonic testing prior to hardness testing. And given the competitive nature of Pro Stock racing if one is doing it then most likely all of them are doing it.   

Cast iron is usually tested using a Brinnell protocol instead of Rockwell. Rockwell uses a a point, in most cases, and Brinnell uses a much greater diameter ball. Both ways measure the resistance to penetration of the tested material. In a non-machined area it's necessary to create a smooth spot for the test in such a way that the spot is at a right angle to the penetrator, and completely uniform.

KS

[RJP]

I know people that check hardness of Sleeves but never anybody check a iron block though probably not a bad idea

Not true, Several years ago I witnessed a Rockwell hardness testing on a pair of Dodge Pro Stock blocks at a machine shop in the central valley, Ca. for Panella Racing. Each block was tested on several locations of each block checking for casting uniformity and hardness consistency. Each probe was done on various non machined areas of the castings. This was done to confirm that the castings were exactly what they were paying for correct CGI material. Panella had done the sonic testing prior to hardness testing. And given the competitive nature of Pro Stock racing if one is doing it then most likely all of them are doing it.   

Cast iron is usually tested using a Brinnell protocol instead of Rockwell. Rockwell uses a a point, in most cases, and Brinnell uses a much greater diameter ball. Both ways measure the resistance to penetration of the tested material. In a non-machined area it's necessary to create a smooth spot for the test in such a way that the spot is at a right angle to the penetrator, and completely uniform.

KS

Keeping in mind this was 8-10 years ago and I was nothing more than a casual observer they did indicate they were testing using the Rockwell "C" scale. These were 2 CGI blocks from MOPAR being built by Panella for a unidentified customer, with that said perhaps the testing was unofficial and was done just to satisfy the curiosity of the builder and provide another bit of info for the end user.

[Heo]

I have worked with Rockwell testing you press a pointy diamond in to
the test subject and meassure the width of the indent in a microscope