Don Terrill’s Speed-Talk

i heard once it was the main cap with nickel ,,,

Waiting for CNC BLOCKS to chime in

It might be coincedence, but the 4 or 5 high nickel blocks (10 20) I have, both 350 and 400, have significantly less bore wear.

The 010 blocks are different casting in the main webbing area compared to the 010/020 blocks. The 010/020 block most of the time are drilled and taped above the timing cover.

Over the years I have seen alot of both blocks and in High HP applications on the 010 blocks I do put on splayed caps because of the weaker webbing.

I have seen no differance in cylinder wear between the 2 castings.

The blocks with the 2482 main caps were all 010/020 blocks from what I have seen.

wanakena56 wrote:Small block Chevy high nickel myth busted! I work in a materials lab for an aerospace company. I removed a chip from a casting seam line and performed an SEM/EDS analysis on my 74 350 block casting # 3970010. Numbers under the timing cover are 010, 020, and 509, and discovered that it contains no measureable nickel or tin. This entire high nickel block legend is a hoax. My instrumentation is capable of detecting element concentrations as low as 0.1%. Grey metal cast iron contains carbon, silicon, and iron. If you add as little as 0.2% nickel it would no longer meet the ASTM requirements for cast iron and you would have to call the alloy something other than cast iron.

Thank you for that. I questioned this for years as I never saw/felt/heard a difference while machining or honing. And yes, most of us, shall we say experienced gents (don't believe in the term Old) can hear/see/feel (vibes) the difference between a soft block and a harder one.

wanakena56 wrote:Small block Chevy high nickel myth busted! I work in a materials lab for an aerospace company. I removed a chip from a casting seam line and performed an SEM/EDS analysis on my 74 350 block casting # 3970010. Numbers under the timing cover are 010, 020, and 509, and discovered that it contains no measureable nickel or tin. This entire high nickel block legend is a hoax. My instrumentation is capable of detecting element concentrations as low as 0.1%. Grey metal cast iron contains carbon, silicon, and iron. If you add as little as 0.2% nickel it would no longer meet the ASTM requirements for cast iron and you would have to call the alloy something other than cast iron.

Thanks. I've always thought the the whole - '010' / '020' under the timing cover - thing had absolutely nothing to do with material composition. This myth has been printed so many times everyone just accepts it as truth. For a large-scale foundry operation making thosands of blocks, it just never made sense that they would have different materials for castings that ultimately ended up in the exact same application. Carl's explanation kind-of makes sense, as I can see where the numbers might correlate to various patterns used for cores.

Just to add some more controversy; the 66-67 327 Nova blocks w/high oil filter location were supposed to have a higher nickel content and until the 80's gm aftermarket blocks came out,this was the only small block that could make this claim. Any takers on this?

wanakena56
Got any info on what is contained in nodular iron...and what makes it nodular?
Also
These days the cheap crank pushers like to call a cast crank "cast steel" . What's up with that other than lipstick on a pig marketing?

FDIcrasto. Sounds like the sameo,same-o. Claimed by who?

Dave Koehler wrote:wanakena56
Got any info on what is contained in nodular iron...and what makes it nodular?
Also
These days the cheap crank pushers like to call a cast crank "cast steel" . What's up with that other than lipstick on a pig marketing?

FDIcrasto. Sounds like the sameo,same-o. Claimed by who?

The Scat 80-60-6 is just ductile iron, AFAIK. I guess "cast steel" sounds more impressive than "iron"?

I did a pair of old blocks from the mid to late 60's recently and I could see a visible difference in the material when finish machined as well as a noticable amount of hone load required for a 525 stine and needed to use a softer stone to do the job.

The appearance of the finished block had a surface appearance that was brighter/ shined more then the opther block of the same era. Both these blocks had the 101/202 identifier in the timing gear area.

The block in question also had a loader ring to it then the other block when bored and the chips were different in size and brighter as well.


Any further o[pinions as to why. Like everyone else I thought ni9ckel content in the casting accounted for this
Dave

Why are some blocks harder then others then?

I've heard a lot of the 010/020 2482 cap blocks were used in heavy trucks, industrial, and military applications.

I have always just lurked here, sponging info from all the rest of you, so this is my first post. I work for a foundry that casts ductile iron, so I finally have something intelligent to add.

The hardness of the iron can be controlled by the amount of carbides formed during cooling. Faster cooling = more carbides = harder, but more brittle iron. If you cool it too fast, you can get white iron. Tin or copper can be added to help regain the yield and tensile strength lost. The difference between grey iron and ductile (nodular) iron is the addition of magnesium. Magnesium is what creates round graphite nodules instead of flakes (grey iron). The round nodules are what gives ductile iron it's superior strength. Porosity is controlled through the gating and risering system. Most castings contain some amount of porosity. The trick is to keep it out of machined and/or safety-critical areas.

There should be no difference in alloy content between parting line and thick section material. The parting line flash may contain a slightly higher level of carbides, but since that area is usually ground off, and superficial only, it's metallurgy is not important to the casting as a whole.

Those are the basics, if you want to get down to what % of what alloy does what, that is what the guys in the lab are for, lol.

Hardness comes from composition and heat treating. Carbon content determines iron or steel, among other things. GM foundry is in Defiance Ohio and Mexico. EPA nightmare. Last I was told, the race blocks are done outside of GM. Think Caterpillar. Nodular iron (crankshafts & center sections) is pretty good (heavy) stuff. Production castings are not and never do recall them being special. If it increased costs, it didn't happen. Production parameters are not based on anything to do with racing. Bill Travato at BTR might be able to chime in with some data from Tonawanda. Flint did all the small block stuff. I wouldn't be looking for anything special from production sources. Casting today is much more a science and less crude from back in the 60s-70s. Richard GM, retired.

wanakena56 wrote:Small block Chevy high nickel myth busted! I work in a materials lab for an aerospace company. I removed a chip from a casting seam line and performed an SEM/EDS analysis on my 74 350 block casting # 3970010. Numbers under the timing cover are 010, 020, and 509, and discovered that it contains no measureable nickel or tin. This entire high nickel block legend is a hoax. My instrumentation is capable of detecting element concentrations as low as 0.1%. Grey metal cast iron contains carbon, silicon, and iron. If you add as little as 0.2% nickel it would no longer meet the ASTM requirements for cast iron and you would have to call the alloy something other than cast iron.

I don't doubt your results but you're drawing a very unscientific conclusion. Testing one sample from one location on one block does not produce nearly enough data to prove or disprove your hoax claim. If you want to get serious about it do the analysis with a lot more data. I'm sure there are enough interested in this that many would send you samples along with the corresponding casting numbers.