| Measuring Crank Journal Run Out and Endplay |
When assembly a new bottom end with new bearings its a good idea to measure the endplay on the crank to ensure that it is within spec. Otherwise new thrust washers will be required. At the same time, measure the crank journals to ensure that they are also true and round.
To perform these measurements, you will need a dial indicator and mounting hardware.
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First thing is to put the new crank bearings into the block and caps and install the crank and main caps. Make sure you also install the thrust washers. Then find a suitable mouting point for the dial indicator and position it like so. Zero out the gauge and then using a large slot head screwdriver, pry on the crank between the #3 main cap and counter weight in both directions. Make sure that it is within spec - replace the thrust washers if necessary. |
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Next, remove one main cap at a time and position the dial indicator to measure the crank journal. Zero out the gauge and then rotate the crank slowly and watch the gauge to make sure that the crank journal is true and round. Do the same for all the crank journals. If they are out of spec, then a new crank is required. |
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