kasperwhoo
New Member
- Joined
- Sep 17, 2009
- Messages
- 318
What Will Help Thrust Bearings Survive?
A simple modification to the upper thrust bearing may be beneficial in some engines. Install the upper thrust bearing in the block to determine which thrust face is toward the rear of the engine. Use a small, fine tooth, flat file to increase the chamfer on the inside edge of the bearing parting line to about 0.040" (1 mm).
Carefully file at the centrally located oil groove and stroke the file at an angle toward the rear thrust face only, as shown in the illustration. Avoid contacting the bearing surface with the end of the file. The enlarged chamfer will allow pressurized engine oil from the pre-existing groove to reach the loaded thrust face, without passing through the bearing clearance first (direct oiling).
Since there may be a load against the rear thrust face, oil flow should be restricted by that load, so there shouldn't be a noticeable loss of oil pressure. This modification is not a guaranteed cure-all, but it should help if all other conditions, such as surface finish, alignment, cleanliness and loading are within required limits.
Note: As with all modifications, it is important to find the original cause of the problem before making modifications. Failure to do so may result in a repeat failure.
A simple modification to the upper thrust bearing may be beneficial in some engines. Install the upper thrust bearing in the block to determine which thrust face is toward the rear of the engine. Use a small, fine tooth, flat file to increase the chamfer on the inside edge of the bearing parting line to about 0.040" (1 mm).
Carefully file at the centrally located oil groove and stroke the file at an angle toward the rear thrust face only, as shown in the illustration. Avoid contacting the bearing surface with the end of the file. The enlarged chamfer will allow pressurized engine oil from the pre-existing groove to reach the loaded thrust face, without passing through the bearing clearance first (direct oiling).
Since there may be a load against the rear thrust face, oil flow should be restricted by that load, so there shouldn't be a noticeable loss of oil pressure. This modification is not a guaranteed cure-all, but it should help if all other conditions, such as surface finish, alignment, cleanliness and loading are within required limits.
Note: As with all modifications, it is important to find the original cause of the problem before making modifications. Failure to do so may result in a repeat failure.
