ZR-1 Net Registry Forums - View Single Post - Noticed something interesting on my LT5...

bdw18_123 · 02-18-2010

I was in the garage tonight looking at the numbers on my '90 LT5 that I have on an engine stand and noticed something interesting.

The Mercury Marine numbers stamped on the oil-pan flange, driver's side look like the last part of the "10ZSH..." number was ground out and redone. Mercury Marine stamped the "10ZSH..." number, right?

Apparently, they didn't completely grind out the mistake, you can see very faintly that the end part of the previous number said "X0052299". They must have accidentally stamped the last 4 digits of the VIN instead of the "0001" that was supposed to be there. So Mercury Marine knew the VIN's of the cars that each engine was going in?

Here a picture of the driver's side oilpan flange showing the number:

Then I noticed that the VIN stamp that GM puts on was also re-done (what a coincidence, GM & Mercury Marine both screwed up their stamps on the same engine!). The passenger side transmission-mount flange of the LT5 where the VIN stamp usually is, is stamped out with "X"-type things.

Here is a picture of it:

Reading this from the ZR-1 Net Registry site explained that one:

"GM NEVER re-stamps an engine except for one reason which we will mention below. First, let's discuss the stamping process:

VIN numbers are put into a handle, then stamped on the right rear of the engine, where there is an upright portion. This stamping was done at the third station on the transmission line when the trans was attached to the LT5. Both the trans and the engine were stamped with the same stamp. As this was done manually, there is a chance that a mistake could be made. Sometimes the stamp wasn't changed after a previous stamp was made, maybe the L98 engine stamp was used mistakenly on a LT5. After all, they were both coming down the same line, a ZR-1 no closer than one every three units (there had to be 2 vehicles between each ZR-1 for assembly time purposes).

After the stamping process, the next station performed a quality control inspection, verifying the VIN stamped matched the build sheet. If a problem is discovered, there were alternate locations for a re-stamp. After the wrong VIN was XXXX'd out, the correct stamp was made on the opposite side of the engine, near the same place. Same with the trans."

The correct VIN was then re-stamped on the driver's side flange (the "9's" are hard to see, but they are there):

The transmission VIN stamp is the correct "1L5802299" though and is not "X'd" out so the LT5 must have gotten stamped before the transmission.

Just thought that that was interesting, so I thought I'd post it up. Anyone else find re-stamps on their LT5's?

02-18-2010	#1
bdw18_123 Join Date: Apr 2009 Location: Prather, CA Posts: 804	Noticed something interesting on my LT5... I was in the garage tonight looking at the numbers on my '90 LT5 that I have on an engine stand and noticed something interesting. The Mercury Marine numbers stamped on the oil-pan flange, driver's side look like the last part of the "10ZSH..." number was ground out and redone. Mercury Marine stamped the "10ZSH..." number, right? Apparently, they didn't completely grind out the mistake, you can see very faintly that the end part of the previous number said "X0052299". They must have accidentally stamped the last 4 digits of the VIN instead of the "0001" that was supposed to be there. So Mercury Marine knew the VIN's of the cars that each engine was going in? Here a picture of the driver's side oilpan flange showing the number: Then I noticed that the VIN stamp that GM puts on was also re-done (what a coincidence, GM & Mercury Marine both screwed up their stamps on the same engine!). The passenger side transmission-mount flange of the LT5 where the VIN stamp usually is, is stamped out with "X"-type things. Here is a picture of it: Reading this from the ZR-1 Net Registry site explained that one: "GM NEVER re-stamps an engine except for one reason which we will mention below. First, let's discuss the stamping process: VIN numbers are put into a handle, then stamped on the right rear of the engine, where there is an upright portion. This stamping was done at the third station on the transmission line when the trans was attached to the LT5. Both the trans and the engine were stamped with the same stamp. As this was done manually, there is a chance that a mistake could be made. Sometimes the stamp wasn't changed after a previous stamp was made, maybe the L98 engine stamp was used mistakenly on a LT5. After all, they were both coming down the same line, a ZR-1 no closer than one every three units (there had to be 2 vehicles between each ZR-1 for assembly time purposes). After the stamping process, the next station performed a quality control inspection, verifying the VIN stamped matched the build sheet. If a problem is discovered, there were alternate locations for a re-stamp. After the wrong VIN was XXXX'd out, the correct stamp was made on the opposite side of the engine, near the same place. Same with the trans." The correct VIN was then re-stamped on the driver's side flange (the "9's" are hard to see, but they are there): The transmission VIN stamp is the correct "1L5802299" though and is not "X'd" out so the LT5 must have gotten stamped before the transmission. Just thought that that was interesting, so I thought I'd post it up. Anyone else find re-stamps on their LT5's? Last edited by bdw18_123; 02-18-2010 at 11:38 PM.