Nickel in blocks???

[MarcDant]

Got no pup in this litter,I know this sounds extreme but as mentioned earlier have a metal composition analysis done between blocks in question (2 small samples of material off each block & compare) at NSL ANALYTICS CLEVELAND OHIO, my former employer & their affiliates used to use $300 - $500. There’s also infinita lab in California I will chip in, not trying to be smart SSA. Thanks Marc

[Steve Shauger]

Lets be respectful to one and other. It's a slippery slope when a theory is purported as fact. I don't want to squelch debate, but facts need to be introduced to support them or mis-information turns into myth and later fact.

I do believe the casting #'s represent running changes for strengthening, manufacturability and various improvements, which are documented with examples. Regarding block material being identified by casting identifiers... well this is completely unproven. We have two notable authorities (John Z. & Bergy) who have firsthand intimate knowledge and have debunked the nickel and tin content variants based on application theories as it relates to Chevrolet built engines.

[70 copo]

Originally Posted by Steve Shauger

Lets be respectful to one and other. It's a slippery slope when a theory is purported as fact.

Steve,

I am curious to ask .. Are the images I posted both real and authentic small blocks?

What is your take on this specifically?

Are these images and what they show a "theory"?

[camarojoe]

Let me start by saying i don't know anything about this topic, nor am I taking sides on the matter...but from what i can tell the images simply show changes to the outward appearances of the blocks over the years, small casting details, etc... How do any of the photos show the actual composition of the iron the blocks were cast from was ever changed? From what I can see, they don't. It would be like posting pics of 67 and 68 camaro fenders and saying because there are outward visible differences, the composition of steel itself must have changed.

[turbo69bird]

We have this same debate w Pontiacs the c118 RAII block is the only as cast 2506 block the rest were 9790071 and they ground off and stamped the rest of that 2506 number. this has led to a debate about that being a high nickel block. Some RAII race cars had that block moved to the next seasons car as they were both considered 2506 blocks NHRA allowed it. Speculation was that it must be Because it was high nickel . (The story the driver gives is it was already balanced and blueprinted and was considered the same block ) saved money.
A few months back I posted a few outward anomalies in the blocks even as cast on the same day . It was explained (by someone from a foundry) as the blocking in the molds for the dipstick tube was differnt and they had just grabbed 2 or 3 of those used on some blocks where others maybe used 1 of them . It is a very similar debate to what you have here w these blocks and around the same time period . M
Interesting coming from a segment of Gm and seeing the same basic debate .

This may help explain why some of the outward differences may have popped up over time with your blocks as well . Rember these differences can be on the same day of casting w the Pontiac block

[70 copo]

Originally Posted by camarojoe

Let me start by saying i don't know anything about this topic, nor am I taking sides on the matter...but from what i can tell the images simply show changes to the outward appearances of the blocks over the years, small casting details, etc... How do any of the photos show the actual composition of the iron the blocks were cast from was ever changed? From what I can see, they don't. It would be like posting pics of 67 and 68 camaro fenders and saying because there are outward visible differences, the composition of steel itself must have changed.

Thank you Joe,

Have a look on the 1969 .20 block under and to the left of the cam gallery and leading to the top of the crank gallery. this is a defined bulge with a crease.

Next look at the 1969 .20 block this time at the more pronounced bulge present above the cam gallery to the right and up to the head deck.

Why is that significantly structurally different from the 1973 block with the same casting number?

So the question Joe is; do you think that the differences in the image are just the the composition of steel that has been "changed"?

[cook_dw]

This could just be a situation where an intelligent mind struggles over the simple truth. The flow path of the castings being changed could result in the cure speed which could result in hardness changing due to cool down of the molten iron. Just because the hardness is different from one block to another doesn't mean the composition changed. Take water for instance. You still have 2 parts hydrogen and 1 part oxygen. Different temperatures give you different results in hardness. I really thing you are making this more complicated than it needs to be.

[70 copo]

Darrell,

Post #66 above.

Same question. Care to offer an opinion?

[70 copo]

Originally Posted by cook_dw

The flow path of the castings being changed could result in the cure speed which could result in hardness changing due to cool down of the molten iron. Just because the hardness is different from one block to another doesn't mean the composition changed. .

Good. Yes the truth is that some blocks ARE harder than others.

Excellent. I wonder if our expert Bergy would agree with you on the remainder of your informed opinion?

[bergy]

I think I'll leave this discussion with an apology to Phil for offending him. I should not have done that. Maybe we can make "lemonade out of lemons" here. The discussion about nickel and tin alloying is put to bed in my mind, since I actually lived the production and know what the processes were.

The discussion about physical changes in casting profiles might be interesting to the group however - I'll start a new thread and contribute what I can.