Engine Building Fundamentals: Measuring Bearing Clearances
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Measuring Bearing Clearances
02.16
| 00:00 | - The process of measuring bearing clearances is to begin by measuring the journal on the crank shaft using a mic. |
| 00:06 | When we're measuring any journal like this with a micrometer we want to take several measurements to ensure that the journal is round as well as parallel. |
| 00:15 | To do this, I'll measure the journal at two points across the journal to check the taper. |
| 00:21 | And repeat this process at a couple of radial locations on the journal to check and make sure that the bearing journal is not out of round. |
| 00:30 | Once we have a measurement for the crank shaft journal, we can use the micrometer and transfer this measurement onto a bore gauge. |
| 00:38 | What we want to do is adjust the dial gauge so that it swings to zero as we sweep the bore gauge across the ends of the micrometer. |
| 00:47 | This is setting the minimum reading of the bore gauge to match the diameter of the crank shaft journal. |
| 00:54 | Next, we need to clean and instal the bearings and bearing caps or cradle. |
| 00:59 | And torque these to the correct specifications. |
| 01:03 | Now, we can use the bore gauge and place in in the bearing and use it to check the clearance. |
| 01:09 | We want to use the bore gauge perpendicular to the parting line in the bearing cap. |
| 01:14 | And gently rock the bore gauge through vertical inside the bearing shells. |
| 01:20 | We're using the same technique here that we use to zero the bore gauge and the micrometer, only this time we want to see what the reading on the bore gauge is when it's at its minimum. |
| 01:32 | As we rock the bore gauge back and forth through the vertical plane, the distance that it's measuring will increase as we move away from vertical and decrease as we move towards vertical. |
| 01:45 | Since when the bore gauge is truly vertical in the bearing shells, this is the shortest distance. |
| 01:51 | And this is what we want to measure. |
| 01:54 | Once we have taken note of the bore gauge reading, we now know what the bearing clearance is for that particular journal. |
| 02:03 | It's important to not make assumptions when we're making these measurements. |
| 02:07 | And each journal on the crank shaft, and then each bearing must be individually measured. |
