Block Numbers

mudjnky · #1 08-13-2007, 10:09 PM

Regarding blocks that have been decked or stamps that are not clearly visible. There is a method that is used to read the serial numbers on guns that have had the numbers ground off. Apparently the metal bruises and with this process you can still read the numbers. Kind of like an X-Ray. Not sure what the process is, just remember seeing it on one of those forensics shows. Anyway, do you think it would work on engine blocks? I'm sure if it would work it would definitely pay off for someone with a high dollar car that needed it. Also, along those lines, would it show a restamp due to different "bruising"? I'm not working on anything, and would no way be able to afford anything where it would matter, I was just curious and thought I would toss it out there and see what everyone thought.

**PeteLeathersac** · #2 08-13-2007, 10:29 PM

I recall reading years back of Corvette guys doing this type of thing...not sure what the process was but I think was used to 'show' the original stampings on restamped engines?.
Similar to what your saying, the castings still retain the imprint of the original stampings deeper down and although decked, still shows when magnafluxed or something similar?.
Haven't heard anything of it in recent years...perhaps since restamps are allowed w/ the 'Vette crowd?.

~ Pete

**Mr70** · #3 08-13-2007, 10:35 PM

You better have a camera on,aimed & focused as this process will indeed raise the stampings,but they disappear in seconds and makes them unable to be lifted successfully again.

**PeteLeathersac** · #4 08-13-2007, 11:19 PM

Wow Rick...if the one-time thing is indeed the case, does that indicate there's a chemical process involved?.
Whatever the process is and if economicaly feasible to do so, wouldn't you think someone involved in altering a block or other items would apply this process before letting whatever it is out the door so no previous stampings could ever show?.

~ Pete

**njsteve** · #5 08-14-2007, 12:45 AM

There are indeed several processes used by law enforcement for viewing milled over/previously stamped serial numbers. Both principles work to provide an image of the stressed metal area that has a more densely concentrated molecular signature (the stamped numbers) than the rest of the engine pad (the unstamped area). One involves heat, which is a one-time-only process that requires photos to be taken of the area in a very time sensitive manner as the image fades rapidly and is gone forever as the molecules in the metal move back to their prestressed (prior to stamped) condition. The other method involves chemicals that can make the prvious stamping visible to the naked eye. Consult with your local forensic evidence person for more details. If you have a large county sheriff or prosecutor's office in the area you may want to broach the subject (no pun intended) with them. Many times they are actively looking for items of non-evidentiary value that they can practice their procedures on without risking blowing a criminal case if the process doesn't provide the desired result.

Sincerely,
Cliff Clavin, resident expert on useless trivia.

**PeteLeathersac** · #6 08-14-2007, 02:01 AM

It's all good info 'Cliff' and far from useless!.
Here's a link below to one process and how it works..poor grammar and all!.
Hopefully nobody here has any knots in their stomachs reading this thread?.

http://myforensiclab.blogspot.com/20...ehicle-id.html

~ Pete

**SuperNovaSS** · #7 08-14-2007, 03:13 AM

There is a multiple page discussion on this in the archives of this site.

Jason

**njsteve** · #8 08-14-2007, 03:26 AM

Do you have the link?

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