10 replies to this topic

[kudu]

Hi All,

I was just wanting some information on the cast numbers on an engine block, as its something I've never learnt. And yes I did use the search function for cast numbers, and still didn't find the answer, So here I am. In particular I was wanting to decipher the markings in the photo below. So what do they tell you and how do you read them.

Thanks Scott

 

 

Attached Files

•  Cast Number.jpg   138.61K   7 downloads

[yel327]

Looks like 11D4 which is 11th April 1974, 1984 or 1994. This is the date the pattern was used to make a green sand casting mould to pour the block iron into. The number is on a metal tag held onto the timber pattern with 2 x screws which you can see the heads of either side of the code. The clock face is the time of day the pattern was made/used which is 7am or 7pm. SBC blocks have an A, D or N on them for the shift as well.

[kudu]

Looks like 11D4 which is 11th April 1974, 1984 or 1994. This is the date the pattern was used to make a green sand casting mould to pour the block iron into. The number is on a metal tag held onto the timber pattern with 2 x screws which you can see the heads of either side of the code. The clock face is the time of day the pattern was made/used which is 7am or 7pm. SBC blocks have an A, D or N on them for the shift as well.

 

Thanks for that.

My SLR is an October 74 build with quite an early engine number. So that fits. I've always wondered about that clock face.. Now you explain it, it is obvious.

Cheers.

Edited by kudu, 25 July 2024 - 04:47 PM.

[Bruiser]

Good to know
I have wondered about all this a little bit too
Is there a way of picking which decade from the numbers?
Why would they bother putting a clock on there as if the
Hour of casting was important, but not indicate am or pm?

Are those round flatblade screwhead castings outies, or innies?
I always thought outies

Edited by Bruiser, 25 July 2024 - 06:12 PM.

[yel327]

Good to know
I have wondered about all this a little bit too
Is there a way of picking which decade from the numbers?
Why would they bother putting a clock on there as if the
Hour of casting was important, but not indicate am or pm?

Are those round flatblade screwhead castings outies, or innies?
I always thought outies

You can pick by other telltales:

1974 will have 308 on one side.
1984 will have 308 on both sides.
1994 will probably have 5.0L on both sides but if post introduction of the 350ci (5.7L) engines it will be blank on both sides.

I can’t remember if Holden V8 had a D or N or A somewhere else for the shift. Or maybe they only prepared the patterns in the morning at Fishermans Bend so they are always AM.

They are screw heads, where the screws held to metal plate to the timber pattern. The green sand gave you the reverse of the pattern and then the iron replicated the timber pattern with metal plate screwed on.

[yel327]

Basics shown here:
https://www.generalk...g/sand-casting/

[claysummers]

In addition, the engine number stamping, assuming it is present and honest, will generally confirm the decade by simple sequencing by comparison.


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[yel327]

As Clay says too. Plus any patterned/cast in 1969-1972/3 (can't remember the exact time it changed) will use the US date format so the subject block above would be in the form D114 not 11D4. I think the V8 hang on longer than 6cyl with the US date form. 

[Bruiser]

Cheers, chaps

[Shiney005]

As Clay says too. Plus any patterned/cast in 1969-1972/3 (can't remember the exact time it changed) will use the US date format so the subject block above would be in the form D114 not 11D4. I think the V8 hang on longer than 6cyl with the US date form. 

I've got E 18 3.  11QT (308)

            7 F 3.     11QT (308)

 

            D 19 3.   QR (253)

            10 G 3.   QR (253)

 

            A 21 1.    3100X (186)

            7 G 1.      2250H (138)   There is also a G 19 1  CK186, but this one seems to be an anomaly.

[yel327]

I've got E 18 3.  11QT (308)

            7 F 3.     11QT (308)

 

            D 19 3.   QR (253)

            10 G 3.   QR (253)

 

            A 21 1.    3100X (186)

            7 G 1.      2250H (138)   There is also a G 19 1  CK186, but this one seems to be an anomaly.

 

There could be crossover too Laurie, remember they were making engines not history! People may have come back from holidays and used the wrong brass tags. That aligns with what I though too, V8 stayed with the US coding longer. It looks like the 6cyl change might go close to aligning with HQ engine introduction.