Author Topic: DZ stamp  (Read 1637 times)

67 kemie ss

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DZ stamp
« on: June 17, 2014, 04:20:19 AM »
Stamp or re-stamp?  

Thanks

z28z11

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Re: DZ stamp
« Reply #1 on: June 17, 2014, 04:30:35 AM »
Difficult to tell for sure - stamping appears correct, but the block surface looks a little weird. No real obvious evidence of broaching lines - surface almost looks shot peened, or blasted, but it could be O.K. I don't think the Van Nuys VIN stampings ever made it to the block side as did Norwood's above-the-filter stampings, so at least that matches.

Without a larger view of the deck surface, it would be difficult to pronounce a verdict one way or the other. At least no decking lines visible -

Regards
1968 Z28 M21/U17 BRG/W
1969 Z28 X77/M20/VE3 LeMans/W
1969 L78 X66/N66 Cortez/BVT
1969 Z11 L48/M35/C60/C06

1968RSZ28

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Re: DZ stamp
« Reply #2 on: June 17, 2014, 07:30:31 AM »

69Z28-RS

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Re: DZ stamp
« Reply #3 on: June 17, 2014, 12:49:36 PM »
Due to the fact that the stamp appears OK, and the deck surface around it appears 'aged/old'..  doesn't appear to have been machined any time recently...  I'd lean towards it being correct...   if all other indicators were good re the engine...
Gary W / 09C 69Z28-RS, 72 B 720 cowl console rosewood tint
69 Corvette convertible, silver/black 350 hp,
60 Corvette white/red, 72 Corvette coupe, '70 Mach I 
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firstgenaddict

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Re: DZ stamp
« Reply #4 on: June 18, 2014, 03:40:09 PM »
The double tap on the Z also leads me to believe it is real.
I read a metallurgical engineer's statement recently that using a thermal imaging camera on a tripod, start the engine, allow to come to operating temp, then cut it off, take a pic of the pad every 15 minutes and the original stamp will appear. Said that you couldn't grind away enough of the pad to get rid of it and still have the block useable. I'd like to see if this works... anyone have a TI camera?
James
Collectin' Camaro's since "Only Rednecks drove them"
 
Check out the Black 69 RS/Z28 45k mile Survivor and the Lemans Blue 69 Z 10D frame off...
https://plus.google.com/photos/112392262205377424364/albums?banner=pwa

cook_dw

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Re: DZ stamp
« Reply #5 on: June 18, 2014, 03:54:15 PM »
I have a thermal imaging camera that I use at work.. I actually was using it this morning.  Its a Fluke Ti32.    Hmmm..  They only cost about $8K
Darrell Cook
1967 LeMans Blue SS/RS L35 clone
1968 Rallye Green SS L78 - unrestored original
1968 Matador Red Z28

cook_dw

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Re: DZ stamp
« Reply #6 on: June 18, 2014, 06:08:52 PM »
I have a decked bbc at home.  Ill take the "tic" home and see if the numbers show up when I apply heat from a propane torch.  Should be a good test.
Darrell Cook
1967 LeMans Blue SS/RS L35 clone
1968 Rallye Green SS L78 - unrestored original
1968 Matador Red Z28

cook_dw

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Re: DZ stamp
« Reply #7 on: June 18, 2014, 11:12:54 PM »
Ok I have attempted the TIC trick and I see nothing.  Maybe I am not getting it hot enough before letting it cool.  I should have grabbed the tripod but forgot it at work.  Also this is a bare block and it may need the entire engine brought to temp.  IDK  I plan on trying again later on when the temps in the garage drop below 90...









Darrell Cook
1967 LeMans Blue SS/RS L35 clone
1968 Rallye Green SS L78 - unrestored original
1968 Matador Red Z28

firstgenaddict

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Re: DZ stamp
« Reply #8 on: June 19, 2014, 02:59:19 AM »
Blue is coolest I expect, if so then there is no deep radiating heat and the pad itself is not 100 deg, correct?
I think there are faints of some characters the way it was described to me was the engine needed to be brought up to temp then the pic every 10 or 15 min through cool down. The heat cycle will be completely different and hold longer vs heating the pad directly, maybe a rosebud on an oxyacetylene torch working in large circles under the pad.
If you had a industrial parts washer for cleaning engine parts it may work since the block is completely heated, hell leaving it outside one afternoon around here would get it 120.
James
Collectin' Camaro's since "Only Rednecks drove them"
 
Check out the Black 69 RS/Z28 45k mile Survivor and the Lemans Blue 69 Z 10D frame off...
https://plus.google.com/photos/112392262205377424364/albums?banner=pwa

cook_dw

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Re: DZ stamp
« Reply #9 on: June 19, 2014, 11:37:32 AM »
On the right you will see the color scales vs temp.  Black and then purple is the coolest.  This scale will change once it sees temps above or below its calculated range and will recal for that.  I tried this again later on last night and got the pad extremely warm (around 200*F) and I allowed it to cool and took a few shots of it and still could not see anything materializing.  I need to try this with an engine that is running and use the tripod and do the 15 min photo cycles.  I believe it will work I just need to nail down the process.
Darrell Cook
1967 LeMans Blue SS/RS L35 clone
1968 Rallye Green SS L78 - unrestored original
1968 Matador Red Z28

Mike S

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Re: DZ stamp
« Reply #10 on: June 19, 2014, 09:34:59 PM »
 I have seen people try this method before and never once seen it work.
I suspect a lot has to do with the original impact of the characters and the depth of the milling.

Mike
67 LOS SS/RS L35 Hardtop - Original w/UOIT
67 NOR SS/RS L35 Convertible - Restored

KurtS

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Re: DZ stamp
« Reply #11 on: June 20, 2014, 03:03:02 AM »
Restamp.
Kurt S
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firstgenaddict

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Re: DZ stamp
« Reply #12 on: June 20, 2014, 04:28:30 PM »
I have seen people try this method before and never once seen it work.
I suspect a lot has to do with the original impact of the characters and the depth of the milling.

Mike
Take this with a grain of salt as I haven't ever seen it done, however the engineer stated that "you couldn't grind enough metal away to get rid it without ruining the block".
James
Collectin' Camaro's since "Only Rednecks drove them"
 
Check out the Black 69 RS/Z28 45k mile Survivor and the Lemans Blue 69 Z 10D frame off...
https://plus.google.com/photos/112392262205377424364/albums?banner=pwa