04-13-2021, 02:12 AM
I'm reading in the FSM about how the crank has different sized bores and journals.................
1. Ensure main bearing caps are numbered for location and arrow on cap points toward timing belt end of
crankshaft.
2. Cylinder block main bearing bore size is indicated by a letter "A", "B" or "C" stamped on cylinder
block. See Fig 9. Ensure main bearing bore is within specification. See MAIN BEARING BORE
SPECIFICATIONS table.
3. Crankshaft main bearing journal size is indicated by numerical size mark located on crankshaft
counterweight end. See Fig 10. Ensure main bearing journal is within specification. See MAIN
BEARING JOURNAL DIAMETER SPECIFICATIONS table.
4. If main bearing journal and main bearing bore are within specification, replace main bearings with
original size grade (color code). If color code on original bearing cannot be obtained, use size mark
letter on cylinder block and number on crankshaft to determine proper size main bearing to be used.
See MAIN BEARING SELECTION (STANDARD BEARINGS) table. Standard bearing thickness is
as listed. See BEARING THICKNESS SPECIFICATIONS table.
5. Main bearings are available in .010" (.25 mm) undersize. Undersize bearings are coded with 2 color
code marks. See Fig 11 and Fig 12 . Undersize bearings
If I'm reading all of this correctly it sounds similar to the "gang boring" done to the cylinders in that all of the crank journals are not necessarily the same size and each needs a bearing that matches whatever size the each of the journals actually are. Is this because the inside diameter of each of the cranks 5 bores in the block could be different? Were the blocks not line bored by the factory so that all 5 bores are in line and the same size?
Here's my question, if I have my machine shop grind and polish the crank .010 do I also need to get the block line bored so all of the bores are the same size and will work with aftermarket .010 undersized bearings or do I need to find these color coded bearings that are specific to each of the 3 possible crank bores?
1. Ensure main bearing caps are numbered for location and arrow on cap points toward timing belt end of
crankshaft.
2. Cylinder block main bearing bore size is indicated by a letter "A", "B" or "C" stamped on cylinder
block. See Fig 9. Ensure main bearing bore is within specification. See MAIN BEARING BORE
SPECIFICATIONS table.
3. Crankshaft main bearing journal size is indicated by numerical size mark located on crankshaft
counterweight end. See Fig 10. Ensure main bearing journal is within specification. See MAIN
BEARING JOURNAL DIAMETER SPECIFICATIONS table.
4. If main bearing journal and main bearing bore are within specification, replace main bearings with
original size grade (color code). If color code on original bearing cannot be obtained, use size mark
letter on cylinder block and number on crankshaft to determine proper size main bearing to be used.
See MAIN BEARING SELECTION (STANDARD BEARINGS) table. Standard bearing thickness is
as listed. See BEARING THICKNESS SPECIFICATIONS table.
5. Main bearings are available in .010" (.25 mm) undersize. Undersize bearings are coded with 2 color
code marks. See Fig 11 and Fig 12 . Undersize bearings
If I'm reading all of this correctly it sounds similar to the "gang boring" done to the cylinders in that all of the crank journals are not necessarily the same size and each needs a bearing that matches whatever size the each of the journals actually are. Is this because the inside diameter of each of the cranks 5 bores in the block could be different? Were the blocks not line bored by the factory so that all 5 bores are in line and the same size?
Here's my question, if I have my machine shop grind and polish the crank .010 do I also need to get the block line bored so all of the bores are the same size and will work with aftermarket .010 undersized bearings or do I need to find these color coded bearings that are specific to each of the 3 possible crank bores?