Saginaw Metal Casting plant turns 100

[Terry M.]

The place that made most iron Corvette Small Blocks and their associated parts:

http://gmauthority.com/blog/2019/08/gm-saginaw-metal-casting-plant-celebrating-100th-anniversary/

[Mark E.]

Re: Saginaw Metal Casting plant turns 100

So Saginaw is the foundry for small blocks? What about big blocks?

I assumed castings were done at the engine assembly plants (Flint, Tonawanda). If not, are there markings that identify the foundry for castings?

[Terry M.]

Re: Saginaw Metal Casting plant turns 100

So Saginaw is the foundry for small blocks? What about big blocks?

I assumed castings were done at the engine assembly plants (Flint, Tonawanda). If not, are there markings that identify the foundry for castings?

Those small blocks assembled at Flint were, for the most part, cast at Saginaw.* There were no casting facilities at Flint. It was strictly a machining and assembly Plant. (BTW: when they closed Flint Engine Assembly they had assembled something like 50Million small blocks from 1955 to 1999). The Saginaw Metal Casting Plant (that is the current name.) is a fairly short distance from Flint Assembly (IIRC about 40 miles, but the Michigan guys will correct me if I am wrong) and there was a constant stream of trucks providing raw (un-machined) iron castings to Flint (Saginaw cast cylinder heads, water pumps, exhaust manifolds, & oil pumps in addition to cylinder cases). Back in the day both plants were jumping places with multiple shifts. I was told the foundry (Saginaw) ran 27/7 because they couldn't let the furnaces cool down -- except for re-lining them.

Those engines assembled at Tonawanda (both BB & SB) were cast there. Tonawanda cast and assembled SB for passenger cars and trucks. Except for the note below SB Corvettes got Saginaw cast cylinder cases and all those Corvette engines were machined and assembled at Flint. As an aside Tonawanda also cast and assembled engines for Corvair and more recently Pontiac (the Iron Duke) and I am sure engines for other applications.

*We have found a small number of SB Cylinder Cases cast at Tonawanda and shipped to Flint for machining and assembly. We have established this in early C3s, but I suspect this happened in a wider range of years than we have so far established.

The cylinder cases cast at Tonawanda had a different casting number than those cast at Saginaw. In addition Tonawanda castings generally had a T cast into them someplace. The machining operations for cylinder cases at Flint were different than those machined at Tonawanda. One of these differences is easy to identify, and the judges look for it.

Nothing to do with Saginaw, but a good article by John Hinckely about Flint Engine Assembly:

http://www.camaros.org/pdf/flint_engine.pdf

This article will give you some idea of the scope of operations at these two plants in the old days. The number of engines produced is staggering.

[Joe L.]

Re: Saginaw Metal Casting plant turns 100

Those small blocks assembled at Flint were, for the most part, cast at Saginaw.* There were no casting facilities at Flint. It was strictly a machining and assembly Plant. (BTW: when they closed Flint Engine Assembly they had assembled something like 50Million small blocks from 1955 to 1999). The Saginaw Metal Casting Plant (that is the current name.) is a fairly short distance from Flint Assembly (IIRC about 40 miles, but the Michigan guys will correct me if I am wrong) and there was a constant stream of trucks providing raw (un-machined) iron castings to Flint (Saginaw cast cylinder heads, water pumps, exhaust manifolds, & oil pumps in addition to cylinder cases). Back in the day both plants were jumping places with multiple shifts. I was told the foundry (Saginaw) ran 27/7 because they couldn't let the furnaces cool down -- except for re-lining them.

Those engines assembled at Tonawanda (both BB & SB) were cast there. Tonawanda cast and assembled SB for passenger cars and trucks. Except for the note below Corvettes got Saginaw cast cylinder cases and all Corvette engines were machined and assembled at Flint. As an aside Tonawanda also cast and assembled engines for Corvair and more recently Pontiac (the Iron Duke) and I am sure engines for other applications.

*We have found a small number of SB Cylinder Cases cast at Tonawanda and shipped to Flint for machining and assembly. We have established this in early C3s, but I suspect this happened in a wider range of years than we have so far established.

The cylinder cases cast at Tonawanda had a different casting number than those cast at Saginaw. In addition Tonawanda castings generally had a T cast into them someplace. The machining operations for cylinder cases at Flint were different than those machined at Tonawanda. One of these differences is easy to identify, and the judges look for it.

Nothing to do with Saginaw, but a good article by John Hinckely about Flint Engine Assembly:

http://www.camaros.org/pdf/flint_engine.pdf

This article will give you some idea of the scope of operations at these two plants in the old days. The number of engines produced is staggering.

Terry------


Tonawanda produced big block castings until 1984. At that time the Tonawanda Foundry, co-located with the engine plant, was shut down permanently. After that time, big block engine engine blocks and cylinder heads were cast at the GM Defiance, OH gray iron foundry and machined/assembled at the Tonawanda engine plant. Obviously, all original Corvette big block engine blocks and cylinder heads were cast at Tonawanda.

Big block forged crankshafts and connecting rods were produced at the Tonawanda Forge which was located very near the engine plant. I don't know where big block cast cranks were produced. I suspect it was the Defiance, OH nodular iron foundry which is where small block cast cranks were cast.

Big block cast aluminum pistons were manufactured at the GM Bedford, IN aluminum foundry and machined at Tonawanda. Forged aluminum pistons were manufactured by TRW and machined at Tonawanda.

I do not think that Corvair engine blocks and heads were cast at Tonawanda although the Corvair engines were machined and assembled at Tonawanda. I believe the Corvair engine blocks and heads were cast at a GM aluminum foundry in Massena, NY.

As far as I know, the only cast iron foundries that GM still operates are the Defiance, OH gray iron foundry, the Defiance, OH nodular iron foundry, and the Toluca, Mexico foundry.

[Terry M.]

Re: Saginaw Metal Casting plant turns 100

As usual you are right Joe. I tried to gather in as much information as possible and in doing so made a mistake about the Corvqir engine casting. In those years Tonawanda Foundry did not have the capability to cast aluminum pieces.

Thank you for the additional information about the BB engine internal pieces. John Hinkley's article that I referenced mentions the source of Small Block internal pieces.

[Manuel M.]

Re: Saginaw Metal Casting plant turns 100

*We have found a small number of SB Cylinder Cases cast at Tonawanda and shipped to Flint for machining and assembly. We have established this in early C3s, but I suspect this happened in a wider range of years than we have so far established.

The cylinder cases cast at Tonawanda had a different casting number than those cast at Saginaw. In addition Tonawanda castings generally had a T cast into them someplace. The machining operations for cylinder cases at Flint were different than those machined at Tonawanda. One of these differences is easy to identify, and the judges look for it.

Nothing to do with Saginaw, but a good article by John Hinckely about Flint Engine Assembly:

http://www.camaros.org/pdf/flint_engine.pdf

This article will give you some idea of the scope of operations at these two plants in the old days. The number of engines produced is staggering.[/QUOTE]

Has anyone come across small blocks cast at Saginaw , then shipped to Tonawanda for machining and assembly ?? particularly around 1969 ??

[Terry M.]

Re: Saginaw Metal Casting plant turns 100

*We have found a small number of SB Cylinder Cases cast at Tonawanda and shipped to Flint for machining and assembly. We have established this in early C3s, but I suspect this happened in a wider range of years than we have so far established.

The cylinder cases cast at Tonawanda had a different casting number than those cast at Saginaw. In addition Tonawanda castings generally had a T cast into them someplace. The machining operations for cylinder cases at Flint were different than those machined at Tonawanda. One of these differences is easy to identify, and the judges look for it.

Nothing to do with Saginaw, but a good article by John Hinckely about Flint Engine Assembly:

http://www.camaros.org/pdf/flint_engine.pdf

This article will give you some idea of the scope of operations at these two plants in the old days. The number of engines produced is staggering.

Has anyone come across small blocks cast at Saginaw , then shipped to Tonawanda for machining and assembly ?? particularly around 1969 ??[/QUOTE]

I presume we can add to your question "originally installed in Corvettes" because that is where our expertise and experience is.

I am not aware of such in the 1968 to 1972 area, but your question is interesting.

[Manuel M.]

Re: Saginaw Metal Casting plant turns 100

Has anyone come across small blocks cast at Saginaw , then shipped to Tonawanda for machining and assembly ?? particularly around 1969 ??

I presume we can add to your question "originally installed in Corvettes" because that is where our expertise and experience is.

I am not aware of such in the 1968 to 1972 area, but your question is interesting.[/QUOTE]

The reason why i ask Terry ,
we had 350 Tonawanda motors fitted to Our Holden Monaros back in 1969 here in Australia , 575 made in total. For some strange reason a very small number of these motors featured Saginaw cast blocks but still machined and assembled at Tonawanda . we know of about 10 like this .
Very strange considering the inhouse foundry at Tonawanda

Manuel

[Terry M.]

Re: Saginaw Metal Casting plant turns 100

I presume we can add to your question "originally installed in Corvettes" because that is where our expertise and experience is.

I am not aware of such in the 1968 to 1972 area, but your question is interesting.

The reason why i ask Terry ,
we had 350 Tonawanda motors fitted to Our Holden Monaros back in 1969 here in Australia , 575 made in total. For some strange reason a very small number of these motors featured Saginaw cast blocks but still machined and assembled at Tonawanda . we know of about 10 like this .
Very strange considering the inhouse foundry at Tonawanda

Manuel[/QUOTE]

We were told the reason Tonawanda cylinder cases were sent to Flint for machining and assembly was to ensure that in the event Saginaw couldn't supply raw castings to Flint the Tonawanda castings would fit on the machining and assembly jigs at Flint.

Would Chevrolet have done the reverse? I suppose the response would be another question: Why not?

There are any number of reasons why either foundry would be unable to supply either engine assembly plant. Ensuring an alternate supply of raw castings is just good business sense. We just don't know what we don't know.