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Now that I’m pistons and crank away from having a bare block I’m interested in what all the “other” numbers and letters “tattooed” on my block everywhere mean.
The letters that appear to be hand stamped along the oil rail are particularly interesting to me. Anyone have some sort of “map” of where all the various numbers and letter of a 350 are stamped and how to interpret them?
Are they just to help the assembly technician at the plant to put the bearings in the right order?
ita either been rebuilt or has a secret Aztec Nazca code.
All kidding aside one from the last post in the above link seems plausible...
Bingo! That's awesome Jim!
The idea that it's a scheme that the QA folks used as effectively a shorthand for where the mains bearing clearances fell within the allowable tolerance range is an awesome one.
I talked to my dad about this last night and he said they ordered their 79 L82 pretty early at their VEEEEERY small local dealership and because of the insane number of people who ordered Corvettes that year that there was a long wait to get them and at one of my dad's MANY check-ins on when the car was going to come in they said that GM had actually sold all of the L82 blocks that they had been stockpiling and expecting to be ordered in 1979 and that they had to spin up extra production of more L82 blocks and they were trying to convince him to take some money back and switch his order to an L48 to get it faster. He obviously waited for the L82. But if I remember right this was really way towards the end of the St. Louis plant and they were getting ready to shut it down and move production fully to the new Bolling Green plant, right?
...they said that GM had actually sold all of the L82 blocks that they had been stockpiling...
An engine was ordered for each individual Corvette, in your Dad's case, an L-82. That engine would have been assembled at Flint, shipped to St. Louis, and would have been on hand at the plant before your Dad's car would have been scheduled for assembly. In a real sense, St. Louis was never short of engines.
...if I remember right this was really way towards the end of the St. Louis plant and they were getting ready to shut it down and move production fully to the new Bolling Green plant...
St. Louis remained in production through 8/1/81. Most 81s were assembled at St. Louis.
the stampings tell the production line engine builder which size piston to install to get the proper clearance. back then the machining tolerance were not as good as today so it was mix and match on the assy line
An engine was ordered for each individual Corvette, in your Dad's case, an L-82. That engine would have been assembled at Flint, shipped to St. Louis, and would have been on hand at the plant before your Dad's car would have been scheduled for assembly. In a real sense, St. Louis was never short of engines.
St. Louis remained in production through 8/1/81. Most 81s were assembled at St. Louis.
the stampings tell the production line engine builder which size piston to install to get the proper clearance. back then the machining tolerance were not as good as today so it was mix and match on the assy line
That makes SO much more sense. It's kinda terrifying, but makes way more sense.
-So they'd have multiple piles of pistons with letters stamped on them, based upon the size and then the oil pan rail outside of each piston hole would get a letter stamped on it based upon the same system by someone else, and then it was someone's job to just grab an "H" piston and make sure it goes in an "H" bore and a "K" piston in a "K" bore and so on and so on?
(Now I'm interested in seeing if the pistons have letters on them somewhere...)
Adam,
For a newbie Corvette guy, you have sharp eyes. Too often the archeological evidence is destroyed by the guy who has too much rip-it-apart enthusiasm and no real ideawhat to look at. Keep up the good work!
This is what I found on the oil pan rail and tops of pistons of my 76 L-48. Thanks everyone for clearing up the mystery. Number and letter Written with marker letters and numbers on pistons
10-15-2018, 08:54 AM
Letters along the oil pan rail of block?
