1970 LT1 assembly stamp, an odd one

[Edward B.]

Re: 1970 LT1 assembly stamp, an odd one

I think the first digit is a 3 not a 5, making the number reasonable.

Ok, that makes more sense. So we now know the car is a 1970 COPO Nova. Can't explain the monkey with a hammer stamping, but at least this part is cleared up!

Ed

[Michael W.]

Re: 1970 LT1 assembly stamp, an odd one

Heavy Repair

The pad surface appears to have typical broaching marks but no signs of a grind out. The presence of a VIN stamp suggests that the engine made it to the car assembly plant and was installed in the vehicle in which it was recently found.

Would not an engine that required heavy repair have one/both sets of stamps ground out and reapplied?

[Terry M.]

Re: 1970 LT1 assembly stamp, an odd one

Terry, could you explain how such a situation may have progressed? I know very little about this subject.

Thanks,
Steve

It would be better, much better, if the folks who have the car in their possession, or the owner of the car, posted ALL the data -- rather than have us, and readers of the Yenko board, speculate without all the information. If they want to keep all that data to themselves, then it ALL should be to themselves. I think Mike W had a point, although you are free to think I also have an attitude if you wish. This late at night I tend to get one -- an attitude that is.

Casting numbers and dates from the cylinder case and the heads is the least they could do. How many grams the crank is out of balance seems trivial compared to the questions about the cylinder case stamp. Maybe I missed it, but no one over there seems too concerned about the engine stamp. Perhaps we shouldn't be either. After all, we (except perhaps you Steve) don't have a dog in that race. Oh, and I see no sign of the exhaust manifolds or the AIR pump or brackets. I can guess what happened there, but no mention of it either on the Yenko site. It seems to me those with a dog in the race are less concerned than we are about these details. I am almost of the mind that we should butt out where we don't belong.

[Terry M.]

Re: 1970 LT1 assembly stamp, an odd one

The pad surface appears to have typical broaching marks but no signs of a grind out. The presence of a VIN stamp suggests that the engine made it to the car assembly plant and was installed in the vehicle in which it was recently found.

Would not an engine that required heavy repair have one/both sets of stamps ground out and reapplied?

I was thinking heavy repair at the engine plant, not assembly plant. I don't think assembly plants had facilities or personnel to do engine heavy repair. And yes, I would expect evidence of a previous engine assembly stamp to be obliterated somehow -- usually by a grind out. Photos, particularly those on the Internet, do not allow one close enough examination of the object shown to make the kinds of assessments we are being asked to make here.

This is the first time I have ever commented on a stamp pad image, and I did so in spite of my firm resolve to never make such a comment. Using internet images to make a determination of an engine pad is in my opinion very much like urinating into the wind. And now that I have done so just sit back and watch all the yellow liquid drop all around.

[Steven S.]

Re: 1970 LT1 assembly stamp, an odd one

It would be better, much better, if the folks who have the car in their possession, or the owner of the car, posted ALL the data -- rather than have us, and readers of the Yenko board, speculate without all the information. If they want to keep all that data to themselves, then it ALL should be to themselves. I think Mike W had a point, although you are free to think I also have an attitude if you wish. This late at night I tend to get one -- an attitude that is.

Casting numbers and dates from the cylinder case and the heads is the least they could do. How many grams the crank is out of balance seems trivial compared to the questions about the cylinder case stamp. Maybe I missed it, but no one over there seems too concerned about the engine stamp. Perhaps we shouldn't be either. After all, we (except perhaps you Steve) don't have a dog in that race. Oh, and I see no sign of the exhaust manifolds or the AIR pump or brackets. I can guess what happened there, but no mention of it either on the Yenko site. It seems to me those with a dog in the race are less concerned than we are about these details. I am almost of the mind that we should butt out where we don't belong.

Wow... just wow. No sir I have nothing to do with this car, just wanted to discuss an odd pad stamp which I THOUGHT some of the NCRS guys would appreciate, which I can see now was a terrible idea.

My apologies.

Steve

[Philip A.]

Re: 1970 LT1 assembly stamp, an odd one

Heavy repair got me thinking. If there was a failure of the block, How would that be handled at assembly?

[Michael W.]

Re: 1970 LT1 assembly stamp, an odd one

This was detailed by John H. in a post last week. An engine that failed at the car assembly plant would be returned to the relevant engine assembly plant for repair. Both sets of characters would need to be ground out since the information was no longer correct. A new assembly stamp would be applied at the engine plant with the updated information. The car assembly plant would apply the partial VIN as per normal procedure.

Cars with a double grind out are not that rare and have been documented here before.

This engine is unusual. There is no sign of any grind outs suggesting that a return-and-repair had occured and no known explanation for the hand stamped engine ass'y code or the other clumsy upside down characters.

If you're curious, why not ask the owner of the car for the rest of the info and his possible explanation of what might have happened.

[Steven S.]

Re: 1970 LT1 assembly stamp, an odd one

Michael I posted this question here because the NCRS is in general light years ahead in regards to the detailed knowledge on this type of thing. When I first seen the pad picture I thought this would be a great topic of conversation here, and that's the only reason. I have no part of the car in question, or any other motives other than learning about these cars and how they were built. I appreciate the positive comments I have received here and in private, and am equally disappointed in some of the others.

Getting back on topic I did have the same thought as you about a heavy repair situation resulting in a grind out, so I'm glad you brought it up. This certainly is an odd one.

Steve

[Patrick B.]

Re: 1970 LT1 assembly stamp, an odd one

The pad surface appears to have typical broaching marks but no signs of a grind out. The presence of a VIN stamp suggests that the engine made it to the car assembly plant and was installed in the vehicle in which it was recently found.

Would not an engine that required heavy repair have one/both sets of stamps ground out and reapplied?

I think this was a fine topic for our discussion board because there is a lot of interest in block stamping practices at the Flint and Tonawanda engine plants even if the unusual stamping occurs on a Chevy other than a Corvette. Whatever these plants did with any Chevy engine could just as likely have occured on a Corvette engine. A trip to heavy repair is the favorite reason for oddball stampings. I would like to present an example of an engine that undoubtedly went to heavy repair.


The photo below is of a rubbing I took off a 351 427 block with a casting date of November 18, 1966. Forgive the photo of a rubbing, this was from a time when digital photograghy of blocks was uncommon. This block was first assembled with a stamping of T1208II which was a 67 big Chevy with a 427/385 manual trans with A.I.R. However, it must have been disassembled for parts in heavy repair. The block appears again over 6 months later with an engine stamped T0615JL. The previous stamp was not ground out, merely stamped over. This engine made into a car with a VIN derivative 7U170297. This was a 67 big Chevy built in the Lordstown, Ohio plant. The code JL cannot be found in listings of 67 BB codes, but it must be a late 67 code introduced after the parts books and other literature were published. Note the absence of grind outs.

[Jim D.]

Re: 1970 LT1 assembly stamp, an odd one

I appreciate the positive comments I have received here and in private, and am equally disappointed in some of the others.
Steve

Steve, You have to take some of the replies with a grain of salt. Consider the age of many members and the fact the some should greatly increase their fiber intake.

[Steven S.]

Re: 1970 LT1 assembly stamp, an odd one

Thank you both, and Jim you put a smile on my face.

Pat that is quite interesting, really reinforces the fact that there are many scenarios we have likely never seen before. If some poor individual had that situation in a corvette they would probably have it decked off and restamped in a typical fashion. It would be a nightmare trying to defend it constantly.

Back to the LT1 pad, it does appear most if not all of those characters were stamped with a heavy lean to the right, not sure if that has any significance in trying to understand what may have happened. Also, knowing the type of stamp used in those gang stamp holders makes me wonder how one would be able to use one effectively with the cylinder head in the way, but I suppose it's not impossible.

Thanks,
Steve

[Edward M.]

Re: 1970 LT1 assembly stamp, an odd one

So help educate us on "heavy repair". I understand the concept, but not the process.

What would happen if the engine had an issue before being stamped at the engine plant?
What would happen is the engine had an issue after being stamped at the engine plant?

What would happen if the engine got to the vehicle assembly plant without having been stamped at the engine plant?

[Edward M.]

Re: 1970 LT1 assembly stamp, an odd one

The first picture of just the Flint code looked like a joke. But the vin is a perfectly authentic Wilmington plant Nova vin. A replacement block would not have had a vin stamped like that by even the most diligent dealer. It certainly seems like the engine arrived at Wilmington with a crude hand stamped Flint code. But why was not even part of the Flint code gang stamped? I've never seen anything like it.

Does the "V" character look like two separate hits with a straight line (like perhaps a chisel)?

[Patrick B.]

Re: 1970 LT1 assembly stamp, an odd one

Does the "V" character look like two separate hits with a straight line (like perhaps a chisel)?

No. I think it is just a "V" single hand stamp hit with an off-center blow (like the 0 and 5 ) giving one side of the V a much different appearance than the other. Understanding that 2 of the indistinct characters in the VIN are actually 3's and that the W stands for Willow Run rather than Wilmington, I think the VIN was definitely stamped at the Nova plant and that this engine is a rare example of the Flint plant stamping an engine with individual hand stamps rather than a gang stamp. Why is the subject of our speculation.

[Terry M.]

Re: 1970 LT1 assembly stamp, an odd one

So help educate us on "heavy repair". I understand the concept, but not the process.

What would happen if the engine had an issue before being stamped at the engine plant?

What kind of issue did you have in mind? Each part was inspected, and if it failed inspection would not be used. There was another identical part nearby -- so I'll ask again; what issues would the "engine" have before being stamped?
Just for the edification of everyone:For all V8 engines: Flint stamped the engines with the heads on, and Tonawanda stamped the engines before the heads were installed.

What would happen is(if?) the engine had an issue after being stamped at the engine plant?

The engine assembly was inspected for oil pressure, coolant passage pressure, rotational balance and timing set at the "hot fire" stand. Most failures would take place at this station. The failed engine assembly (that is the entire engine) was tagged and sent to the Heavy Repair area. Engines might accumulate for weeks or months until a critical number was reached, at which point workers would be assigned to tear down the assemblies and make them into functioning units. Sometimes enough salvageable pieces were among those engine assemblies waiting for repair and sometimes additional specific parts had to be brought into the heavy repair area. What they were made into was determined by the assembly plant orders waiting to be filled at that time. The original assembly stamp would be obliterated (how is a whole thread in itself) and a new assembly stamp applied (again how and what form those took is a whole other thread).

What would happen if the engine got to the vehicle assembly plant without having been stamped at the engine plant?

I really don't know, but as far as I know the vehicle assembly plants only had stamps for the VIN derivative and had no stamps for the engine assembly. Based on that knowledge, I would think the answer to your question is: "Nothing." John Hinckley would be able to provide a more informed answer, however.