Crankshaft replacement
A crankshaft is replaced when its journals are worn beyond repair size, it has cracks or scoring after a spun bearing, or the shaft is distorted.
Symptoms
- The crankshaft journals are worn beyond repair tolerance, or show cracks or scoring after a spun bearing shell.
What's included
- Before deciding, we measure the journals with a micrometer and check runout: in many cases the shaft is repairable and can be ground to a bearing repair size, which is considerably less expensive than replacement. If replacement is unavoidable, we select the shaft with dimensional checks and always flush the oil galleries; metal debris from the previous failure quickly damages new bearings. Assembly includes clearance checks with plastic clearance gauge material.
Additional checks
- Checking crankshaft runout with a micrometer
- Selecting the replacement shaft with dimensional checks
- Clearance checks with plastic gauge material during assembly
Why it matters
In many cases the shaft can be reground to a repair size, which is noticeably cheaper than replacement. Metal shavings left in the oil passages ruin new bearing shells within minutes of running.
More details
The crankshaft is replaced when the journals are worn beyond the repair size, there are cracks, scoring after a spun bearing, or the shaft is bent. Before deciding, we measure the journals with a micrometer and check runout: in many cases the shaft can be reground to the bearing repair size, which is noticeably cheaper than replacement. If replacement is unavoidable, we select a shaft with size checks and always flush the oil galleries — leftover debris from the previous failure kills new bearings within minutes of running. Assembly is done with clearances checked using plastigauge.
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Describe the vehicle and symptoms, and we will suggest which check to start with.
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