Double Stamped Pad

[Scott P.]

IMG_9224(1).jpg

Gentlemen, this exercise to for you to decide what the last two numbers of this blocks VIN
are. The 64 300hp Corvette is long gone with the answer to this question so we need for
you to solve the mystery for us.
The engine will be rebuilt and ready for another 64 Corvette.
Thanks Scott

[Jimmy G.]

Re: Double Stamped Pad

this happened more often than you think I think 10 was changed to 09 Friend of mine had a c3 the same way

[Leif A.]

Re: Double Stamped Pad

I concur with Jimmy. My '67 has a double stamped VIN.

[Mike M.]

Re: Double Stamped Pad

big difference I Leif's pad( the double set of numerals are the same numerals, ie , its a bounce back stamping. the OP's pad stamping consists of a different set of numerals. its been y experience that an incorrect vin stamping in st Louis would have resulted in a grind out, which isn't the case with the OP'S PAD. MIKE

[Mark E.]

Re: Double Stamped Pad

big difference I Leif's pad( the double set of numerals are the same numerals, ie , its a bounce back stamping. the OP's pad stamping consists of a different set of numerals. its been y experience that an incorrect vin stamping in st Louis would have resulted in a grind out, which isn't the case with the OP'S PAD. MIKE

So a mistake by a factory worker who didn't grind first? Or maybe the mistake was found and corrected after the car shipped?

[Larry E.]

Re: Double Stamped Pad

Even though the below is not an engine block it shows a "bounce back" double stamp. I think this
is fairly common on GM components. I remember talking to the Late John Pirkle on this subject and
he indicated he did see many on these through out his rebuilding years. Picture Below>(Lower Left "6")

[Mark F.]

Re: Double Stamped Pad

Even though the below is not an engine block it shows a "bounce back" double stamp. I think this is fairly common on GM components. I remember talking to the Late John Pirkle on this subject and
he indicated he did see many on these through out his rebuilding years. Picture Below>(Lower Left "6")

Larry,

If I am not mistaken, I believe some of the round cast parts like that were "roll-stamped"...meaning they were place in a fixture and the "stamp" characters were rolled-in (pressed or crimped) into the round part being "stamped" (alternator; starter housing; etc.).

I don't believe they were hand stamped w/ a gang stamp like the PAD and trans were.

Anyhow, with wear and slight movement of the part or the character within its' holder could make the defect you show.
Others may have more info on that - I know I've seen that somewhere - dunno if it's here on TDB or somewhere else.

[Joe R.]

Re: Double Stamped Pad

Both of the above pads are missing something. Maybe it's just the light!

Then again?????

JR

[Leif A.]

Re: Double Stamped Pad

Both of the above pads are missing something. Maybe it's just the light!

Then again?????

JR

JR,
Does this one give you any more confidence? I've never had anyone question this stamp pad before.

[Owen L.]

Re: Double Stamped Pad

[ATTACH=CONFIG]118801[/ATTACH]

I'm no expert, but I play one on the internet...
I'm inclined to believe this is a factory anomaly. It looks to me like 4121010 was overstamped with 009. What are the odds that the owner of #009 needed a replacement block and found #010?!? And, knew the value of the VIN sequence on the block but didn't bother to hide the previous number before putting his own VIN on there? AND didn't think anyone down the road would notice? (The pad background looks very good too with no rotary machining marks that I can see.)

I think someone loading the gang holder jumped the gun on what number had just been used and what the next # should be.

[Jack M.]

Re: Double Stamped Pad

Because of the various stamp pad images and discussions, I thought this repeat contribution might be helpful.

Whatz the possibility that the double strike/ghost image/second stamp/rebound/bounce was actually performed FIRST... and on purpose? Visualize a line worker holding the gang stamp, placing it on the block, raising the hammer slightly and giving it a 'slight' tap (almost in a setting/adjusting/practice motion) before raising the hammer higher and firmly striking the final stamp. Could the stamp move slightly between the first and final blow? And if the LIGHTER stamp appears UNDER the final stamp... wouldn't that support a theory, that it occurred FIRST?

In this animation (NOT my engine), I isolated the date stamp and moved it over to show the exact correlation of the stamped characters.
Double_Strike-1b.gif

If the photos are taken at hi-resolution, and then zoomed in, you observe a few cases (certainly not all), what appears to be the faint/rebound/bounce stamp carried thru to the DEEPER stamp. It could be a shadow or illusion... I'm not certain. Neither am I a metallurgist, but I can't see how a light 'bounce' (or second stamp) could possibly penetrate to the BOTTOM of the deeper stamp (especially on cast iron). To me, I'd surmise it could occur if the engine pad was initially deformed FIRST by the light/setup tap. That slightly deformed metal, could then cast a different appearance at the base of the SECOND/DEEPER/FINAL stamp.
Double_Strike-1c.jpg

Double_Strike-1d.jpg

Just one additional suggestion... and for you older folks, remember back to the old 'Dragnet' TV series. When they hit the 'Mark VII Limited' logo, it was indeed a DOUBLE STRIKE of the hammer:

[James G.]

Re: Double Stamped Pad

FWIW
I can see the faint indent of a couple of charcters on a third impression at about the same interval and angle down as the very visible 2nd.

[Mark F.]

Re: Double Stamped Pad

...Just one additional suggestion... and for you older folks, remember back to the old 'Dragnet' TV series. When they hit the 'Mark VII Limited' logo, it was indeed a DOUBLE STRIKE of the hammer:

Mr. Morocco,
you have amazing talents !

[Jaime G.]

Re: Double Stamped Pad

Both of the above pads are missing something. Maybe it's just the light!

Then again?????

JR

Could it be that neither pad shows an original pad surface? The surface is always present before any stamping occurs.

[Jack M.]

Re: Double Stamped Pad

Mr. M,
you have amazing talents !

Naaa... just too much spare time (and a better alternative to doing laundry or cleaning the house). LOL

BTW- I can clearly see the broach marks in the top (1st) image... the other image is at an acute angle, with a little harsher lighting.
I seriously doubt that the pad surface was totally consistent... would new blades leave the same surface texture as worn blades?
Were all Corvettes stored in a hermetically sealed environment? Itz just one aspect of an evaluation... also called, a best guess.