Engine Block production date casting numbers
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WarWagon
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The later blocks '85 and up have a number sequence cast into the pad on lower drivers side near the 3.8 liter designation
The early blocks mid '75 to '84 have a number sequence on the top of the bell housing flange at the rear of the block.
I'm certain that those numbers will correspond to a date but no dates are actually cast on the blocks.
The early blocks mid '75 to '84 have a number sequence on the top of the bell housing flange at the rear of the block.
I'm certain that those numbers will correspond to a date but no dates are actually cast on the blocks.
Anthony P
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I'll add a few notes...
VIN PAD STAMPING ON ENGINE BLOCK:
On the lower, driver side rear part of the block is the VIN stamp block - a machined flat surface that is stamped with the last 8 digits of a VIN as well as a preceding number to represent what GM division. Buick is GM division #4. Think for #'s matching car, the engine VIN stamp, trans case VIN pad stamp, frame stamping and dash VIN plate would match.
In the pic below, the engine pad stamping shows 4 H P 4 4 9 0 2 0
4 = Buick Motor Division
H = 1987 production model year
P = Pontiac Assembly
then numerical last six digits of VIN.
If an engine was sourced from GM as a complete replacement engine, or as a long block assembly, or as a short block assembly, the VIN stamp pad is blank since the engine assembly was not installed into a car during factory assembly
BELL HOUSING FOUNDRY PRODUCTION DATE:
On the top of the bell housing area, near the provision for the knock sensor, the foundry cast the date the block was made. Also, the area shows whether the block was made on DAY or NIGHT shift. All the blocks have this provision.
The '89 SGI block based engine shown below has the foundry marking B039 => February 3, 1989 as well as the tick mark noting D for DAY production. This is a complete GM replacement engine so the VIN pad is not stamped.
The 109 blocks cast during the 1986 and 1987 model years have two foundry date locations. The bell housing area would be stamped accordingly. Also, the front of the block, passenger side, at the raised spot at the timing cover contains a stamping showing the month and day of the month.
Below is a 1987 production model year 109 block showing foundry mark A137 => January 13, 1987 and N for NIGHTSHIFT casting production.
The foundry date on the front of the block shows A13. See pics below.
The 1985 and earlier blocks will have the bell housing foundry casting date but not the front casting for month / day of month. The '89 109 SGI engine does not have the front casting date like the '86 - '87 model year 109 blocks did.
109 block based complete engines, long block assemblies and short blocks were available well into the early 1990's from GM.
The oil testing industry used the 3.8L engine as one of their long term test mules to 1998(?), I think. While a 109 bare block or engine assembly is some format was not available to the retail public after about 1992 or 1994, GM was still making 109 blocks and building 109 block based engines for the oil testing industry until about 1998.
There are other threads detailing some folks finds acquiring these 109 block test engines from oil test facilities.
VIN PAD STAMPING ON ENGINE BLOCK:
On the lower, driver side rear part of the block is the VIN stamp block - a machined flat surface that is stamped with the last 8 digits of a VIN as well as a preceding number to represent what GM division. Buick is GM division #4. Think for #'s matching car, the engine VIN stamp, trans case VIN pad stamp, frame stamping and dash VIN plate would match.
In the pic below, the engine pad stamping shows 4 H P 4 4 9 0 2 0
4 = Buick Motor Division
H = 1987 production model year
P = Pontiac Assembly
then numerical last six digits of VIN.
If an engine was sourced from GM as a complete replacement engine, or as a long block assembly, or as a short block assembly, the VIN stamp pad is blank since the engine assembly was not installed into a car during factory assembly
BELL HOUSING FOUNDRY PRODUCTION DATE:
On the top of the bell housing area, near the provision for the knock sensor, the foundry cast the date the block was made. Also, the area shows whether the block was made on DAY or NIGHT shift. All the blocks have this provision.
The '89 SGI block based engine shown below has the foundry marking B039 => February 3, 1989 as well as the tick mark noting D for DAY production. This is a complete GM replacement engine so the VIN pad is not stamped.
The 109 blocks cast during the 1986 and 1987 model years have two foundry date locations. The bell housing area would be stamped accordingly. Also, the front of the block, passenger side, at the raised spot at the timing cover contains a stamping showing the month and day of the month.
Below is a 1987 production model year 109 block showing foundry mark A137 => January 13, 1987 and N for NIGHTSHIFT casting production.
The foundry date on the front of the block shows A13. See pics below.
The 1985 and earlier blocks will have the bell housing foundry casting date but not the front casting for month / day of month. The '89 109 SGI engine does not have the front casting date like the '86 - '87 model year 109 blocks did.
109 block based complete engines, long block assemblies and short blocks were available well into the early 1990's from GM.
The oil testing industry used the 3.8L engine as one of their long term test mules to 1998(?), I think. While a 109 bare block or engine assembly is some format was not available to the retail public after about 1992 or 1994, GM was still making 109 blocks and building 109 block based engines for the oil testing industry until about 1998.
There are other threads detailing some folks finds acquiring these 109 block test engines from oil test facilities.
WarWagon
Caustic Cacophony
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That 4.1L span is 4 years, 1980-1984
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