ENGINE ID/SERIAL NUMBERS

[gp]

YIKES!!!
I need HELP! Just noticed that when the machine shop decked my block they decked the ID stamps right off the pad! I took "before" photo's of the stamps for reference, but now what?? How can I get my block authenticly ID'd and retain original value?

[Mike M.]

Re: ENGINE ID/SERIAL NUMBERS

Damage is irreversible. sorry, mike

[Joe L.]

Re: ENGINE ID/SERIAL NUMBERS

gp------

Like Mike says, there's no way to restore it. Also, don't start thinking in terms of forensic techniques to "raise" the numbers using an acid process. This technique is used to determine original stampings on certain metal pieces (like ground off numbers on firearms). It can be used on block deck surfaces, too. However, and this is where the misunderstanding comes in, the process does NOT permanently restore the numbers. It's just a technique used to determine what the numbers were. You already know that so this technique is useless. After "raising" the numbers using this process, the numbers usually fade quickly. Like I say, it's a FORENSIC technique and is NOT a RESTORATION technique, at least not in the context of how we all view the term "restoration".

[Mike M.]

Re: ENGINE ID/SERIAL NUMBERS

GP; by the way, what year and horsepower is your vette? MIKE

[Kurt B.]

Re: ENGINE ID/SERIAL NUMBERS

Would stamping over the old numbers with the correct tool be an option?
I thought I saw such a tool in Hemmings once. Since he already knows the numbers and they are the original /correct numbers for that block, would it still be considered a "restamp" in forgery context?
kurt 26406

[Joe L.]

Re: ENGINE ID/SERIAL NUMBERS

Kurt-----

Basically, I think that it falls into the exact same category as someone who obtains a correct casting number and casting date block. Once the stamped numbers are removed from the block, the block is a correctly dated and correct casting number block----that's all. If the re-stamping can be done in such a way as to be undetectable (broach marks, font size, characteristics, etc.), then the engine will "pass". If not, then it will "fail". I don't see any way that consideration could be given for it being an original block.

But, I'm certainly not the expert on these engine block "numbers". Usually, I try to avoid the subject because I think that it gives too much importance to something that, in my opinion, is WAY, WAY too over-valued and over-discussed.

[Dick W.]

Re: ENGINE ID/SERIAL NUMBERS

Unfortunately you are out of luck. Just stamping the block will not cure your ills. There are good "stampers" out there, but the broach marks are another thing (and another whole thread of about 300 posts). There is no one that can do a 100% set of broachs.

[Rob M.]

Re: ENGINE ID/SERIAL NUMBERS

All,

I can't find out what broach marks are (since I'm Dutch speaking). Can someone explain to me what these marks are ? The dictonairy doesn't help me on this one either...

thanks,
Rob.




the 1959 restauration project

[Mike M.]

Re: ENGINE ID/SERIAL NUMBERS

Rob: when the raw casted engine case was machined, a broaching machine was used to true it up. The upper faces of the case, where the head gasket is positioned, is where an ncrs judge looks for the horizontially located broach marks on the pad of the engine case. these marks are very superficial scratches in the cast iron of the pad . They run front to back . they are impossible to duplicate once removed. mike

[Chuck S.]

Re: ENGINE ID/SERIAL NUMBERS

Rob, imagine that the engine block is a big piece of cheese...now we know what a cheese knife does, only the knife used on the old GM blocks was huge and moved across the "deck" (the surface where the heads bolt) from one end of the engine to the other, making a shaving cut as it moved.

With use, the blades normally develop extremely small nicks and irregularities that left straight line "tracks" in the deck surface as they were machined. Typically, when the blades had just been replaced, there are next to no visible "broach marks", but as the blades were used, the marks become more pronounced. Original engines can have from almost no marks to clearly visible marks.

[Rob M.]

Re: ENGINE ID/SERIAL NUMBERS

As Dutchie the cheese related example was very well choosen ;-)

Thanks both for explaining this mistery !

greetings,
Rob.