Back in June, we attended a Caterpillar 3516 gas engine for a straightforward job – changing the rear main oil seal.
In the end, it wasn’t quite so straightforward – during the investigation, our engineers found something they’d never seen before:
If you missed it, the full story is here: https://bartechmarine.com/blog/unseen-catastrophic-failure/
The engine is now at Bartech HQ in Colchester, we’ve completed the full inspection and dismantle, and sent the crankshaft to have the main bearing surfaces re-ground, taking it to 0.63mm undersize – the first repair stage.
We also had the crankcase main bearing bores checked using laser measuring equipment to ensure the bores were still in line with each other.
When we have it back, we’ll rebuild it with new main bearings, which are suitable for an undersized crankshaft.
We suspect the cause of this damage was a misalignment between the engine and alternator, but as the alternator had already been uncoupled from the engine when we arrived, we were unable to check it at the time.
Once the engine is rebuilt and connected to the alternator, the crankshaft deflections will be measured in our workshop to ensure everything is aligned correctly.
These deflections will be checked once again when the engine has been reinstalled on site.
If crankshaft deflections are not taken during an engine install the whole engine could be out of alignment, leading to issues such as these and, eventually, possible crankshaft failure.
