Regardless of which crank you choose to use during an engine reconditioning or crankshaft crack testing, it is obvious to take the time to check and inspect it in detail. If you are checking a previously used crankshaft, it is also necessary to check its crack testing. If you inspect it before installing, it will clarify its condition and allows to avoid problems.
Though many cracks may be clearly seen once parts have been disassembled and cleaned, other cracks are nearly invisible or may only be seen under special circumstances such as porosity leaks in heads and blocks.) Some cracks are also there which are totally invisible, and normally these kinds of cracks are inside casting.
It is suggested that never assume crankshaft is okay just because you can’t see any visible cracks. Always assume there may be cracks, then you will be able to figure out the crankshaft cracks.
Every work or process have some steps involved through its completion. Same is the case with crankshaft crack testing. In the first and the foremost step, especially when you are dealing with an old or used crankshaft, clean the crank thoroughly.
It is preferred to wash it in a hot tank or with a jet wash. Once it is done, check it for cracks. The crack testing is preferably perfectly done on a magnetic particle inspection station which is known as magnaflux machine. By doing this, the crack is mounted horizontally on the inspection bench and passes through a large diameter circular magnet and is inspected with an ultraviolet black light which is visible as whitish lines.
Crankshaft runout checking is also necessary to get the best testing outcomes of crankshaft crack testing. With the crankshaft mounted level on a pair of level v blocks, set up a dial indicator at the center main journal, also by setting the indicator probe a little bit offset just to avoid hitting the journal’s oil feed hole. If the crank shows less than 0.001 inch runout, it’s considered to be fine. But if the crank shows more than 0.001 inch runout, it need to be either straighten or replace.