What needs to be repaired on a crankshaft? In the field of classic car repair, the answer is almost always the same: because crankshafts wear out almost exclusively in the area of the bearing seats.
They are made of a similar, and to a large extent even identical, material to the camshaft. They have an elastic, flexible core and the surfaces are hardened. The hardened layer here is about 0.2 – 0.3 mm.
What we can do at TM Classic Cars:
We re-armour the highly stressed bearing seats with a wear-resistant material using a laser. To be 100% sure, we check our work afterwards by means of dye penetrant testing (non-destructive material testing, also called red-white testing). In this way we can make visible and close even the finest surface cracks, should they still exist. If desired, we can then restore the dimensional accuracy of the bearing seats by grinding.
Run-in bearing shells of a crankshaft
A metallurgically highly interesting repair:
In our classic car workshop, we have succeeded in developing a unique method of coating the bearing shells of the crankshaft with white metal.
Vintage Rolls Royce, 1927
Run-in crank pin of a crankshaft
Coating with specially adapted, abrasion-resistant material using the laser welding process. Without any distortion.
Oldtimer: Condition of our work before sanding.
Broken-in crankshaft lifting web
The sealing surface of the Simmerring had shrunk. Rebuild by laser by 0.2 mm.
Afterwards, it could be reground to 100ths and the sealing could be exactly restored.
Classic car BMW
Crack at a bearing point of the crankshaft
The crack on one bearing of the crankshaft was localised, the depth of the crack checked and ground out accordingly.
Subsequent filling with adapted additional material, renewed crack inspection (professional dye penetrant inspection) and final grinding.
Above: Vintage car, welding a crack on a bearing of a crankshaft
Below: Result of our professional dye penetration test (red/white test)