Cylinder head date code

[Peter S.]

Re: Cylinder head date code

Cylinder head casting numbers and dates are not judged.

Why not? It can be seen perfectly under the oil cap. We ask owners to remove more complicated items than an oil fill cap.

[Michael W.]

Re: Cylinder head date code

Why not? It can be seen perfectly under the oil cap. We ask owners to remove more complicated items than an oil fill cap.

It can be seen on some cars, not all. A level playing field means that none are judged.

[Peter S.]

Re: Cylinder head date code

It can be seen on some cars, not all. A level playing field means that none are judged.

Since when is judging ever on a level playing field? Higher optioned cars receive more scrutiny than low optioned cars. '69 AC cars may have a dated fan, yet typical 5-blade fans are not dated. Are you saying if you saw a date code that was atypical on a 7-blade fan you would not deduct for it?

[Michael W.]

Re: Cylinder head date code

Peter-

possibly you should direct your concerns to the judging chairman.

[Mark D.]

Re: Cylinder head date code

It doesn't make any difference, in my opinion, whether it is judged or not, whether you can see it or not, or whether it is covered up or not. IF it is important to the owner that the numbers align with build, then they should. I expect when an owner closes his/her eyes, they can clearly see all the numbers, especially the ones that are incorrect.

The last digit in the pics is a 9.

[Steven B.]

Re: Cylinder head date code

I was referring to part number (backwards 9 or upside down 6). 'Didn't do math on date as last digit in PN was odd enough. I wonder how long it took QC to catch this? With cost of molds and production interruption may have let it run.

[John H.]

Re: Cylinder head date code

I was referring to part number (backwards 9 or upside down 6). 'Didn't do math on date as last digit in PN was odd enough. I wonder how long it took QC to catch this? With cost of molds and production interruption may have let it run.

Steve -

Those brass characters forming the casting number and date code were hand-soldered to their brass Tags1 [640x480].JPGbacking plate by Foundry Sevice Workers and then affixed to the pattern(s) manually; there would be a LOT of castings in process in the system before they hit the shake-out table and anyone downstream from there noticed an error. The error on the pattern would get corrected, and nothing would be done to the heads cast with the error with the foundry line running at 600 cylinder heads per hour (one every six seconds).

[Peter S.]

Re: Cylinder head date code

The 3927186 heads were produced for 1969 model year cars, but it would not be impossible for the first castings to have appeared in June of 68. However, your enlarged picture looks more like a 9 than an 8.


A potential problem may be that these are 3927188 heads rather then 3927186 heads. The 3927188 heads were for low compression 327's still in use in full size Chevys in 1969. They used a smaller intake valve (1.72 rather than 1.94) and also had a much larger chamber volume. They did not use the rounded double hump casting symbol on the end of the head like the 186 heads. (They used two vertical bars instead.) If these heads do not have the double hump casting symbol does not use them.

Hi Patrick,

They are 186 cylinder heads indeed.

Steve -

Those brass characters forming the casting number and date code were hand-soldered to their brass [ATTACH=CONFIG]52567[/ATTACH]backing plate by Foundry Sevice Workers and then affixed to the pattern(s) manually; there would be a LOT of castings in process in the system before they hit the shake-out table and anyone downstream from there noticed an error. The error on the pattern would get corrected, and nothing would be done to the heads cast with the error with the foundry line running at 600 cylinder heads per hour (one every six seconds).

John, great picture, I was curious how the casting info was added. How could the so obviously screw up a casting #? Or, did someone have a little fun?

[Steven B.]

Re: Cylinder head date code

Errors happened in manufacturing often. When I was in production management at Maremont Corp in Paulding, Ohio from '72-'74 we got some employees from the Defiance, Ohio GM "Central Foundry". One of the folks from the foundry told me of some PN casting number errors. I believe he told me the errors were ground out and then stamped. As I recall there were not hundreds involved. As a side note the Defiance foundry had a few thousand employees as I recall. The check pools got so large the security guards held the pot. We only had a few hundred employees and paid a lot less, therefore no such precautions were taken. We once received some D8 backing plates stamped incorrectly so we returned them to our supplier. Does anyone have any brake backing plates with PN ground out and restamped??? We had 8,000 drum linings labeled incorrectly and each had to be side ground and relabeled. All of our car linings used silver paint for labels, the heavy trucks used black paint, and clutches used silver paint. Too many errors and the rework got very costly. Steve

[Roger G.]

Re: Cylinder head date code

Cylinder head casting numbers and dates are not judged.

and that's a good thing - they are hard to read :0

Here's a Feb 12, 1969 casting number 3931063
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