Had an RRS recovered in on Monday morning, with a broken engine.
Cue body off:







Bottom end was seized solid, could not turn the engine to remove the torque convertor, so the bottom of the engine was stripped, and this is what greeted me:








Still, a nice low mile 2nd hand engine waiting patiently to be fitted, and be back to its rightful owner by the end of the week

Any idea of the cause Mike? Seems to be a few sports cropping up with broken cranks lately.
What was the mileage/service history ?

The pics are a bit hard to see but I assume it is the old spun bearing then seize issue. Is it the main bearings that are seizing or the big end bearings seizing. Also is there any particular bearing (which position) where the failure occurs and does the crankshaft snap in the same place.

Thanks

Garry 07MY RRS TDV6
Arctic Frost
Aspen Interior

Looking at the pictures and admittedly its a bit hard to see, but the patterns in the broken section look like a classic case of brittle fracture.

Brittle fracture can occur in steels without plastic deformation and without ever reaching the ultimate tensile strength of the material. It is usually initiated by a 'hard spot' ie a section of the material that has become harder than the surrounding material, for whatever reason, usually overheating.

There have been recorded cases of tailshafts on ships snapping that have been traced back to a hard spot caused by weld spatter falling on the shaft. It causes a hard spot, which becomes brittle and microscopic cracks start to form in the surface of the material. A the number of stress cycles increase ( no of rotations ) the cracks get bigger and bigger until eventually bang.

When it goes the cracks move through the steel at supersonic speeds. 2017 3.0 SDV6 Autobiography Santorini Black
2015 3.0 SDV6 HSE Dynamic Indus Silver.
2013 3.0 SDV6 HSE Black Edition, Orkney Grey, 5 Spoke Diamond Turned Alloys, Ebony Premium Oxford Leather, Privacy Glass

67k mlies. No service book in the car

garrycol wrote:

The pics are a bit hard to see but I assume it is the old spun bearing then seize issue. Is it the main bearings that are seizing or the big end bearings seizing. Also is there any particular bearing (which position) where the failure occurs and does the crankshaft snap in the same place.

Well that is interesting - structural defect - that is a worry.

Thanks

Garry 07MY RRS TDV6
Arctic Frost
Aspen Interior