08-01-2018, 04:14 AM
I have no experience of Phoenix cranks but have been involved for decades with Javelins most of which are fitted with relatively reliable aftermarket cranks and many of these originally nitrided. Have followed the subject.
Nitriding greatly increases fatigue resistance and is presumably the reason original undamaged Phoenix cranks are reasonably reliable. The nitride layer is usually thin and more or less removed by grinding and its protective effect then largely lost. Special care is necessary or heat cracks are created. Cranks can be re nitrided but must be free of cracks in the nitride due being dropped, or from blow ups, unskilled grinding etc.. It is an expensive process, opinions differ about the extent and method of final finishing etc. The increase of diameter of main bearing journals a complication. For quality truck cranks etc a second light grind. Firms probably more familiar with now than in the past, when they often ruined.
Nitrided cranks are very hard and should not wear significantly, certainly not with white metal bearings.
I suspect all the crack testing and general mucking about could approach cost of a new one. Whether it can be made to run or not, put in an engine and sell as “Phoenix “ crank! Probably known to the sellers, I have been sold several dud ordinary Seven cranks in ages past.
Nitriding greatly increases fatigue resistance and is presumably the reason original undamaged Phoenix cranks are reasonably reliable. The nitride layer is usually thin and more or less removed by grinding and its protective effect then largely lost. Special care is necessary or heat cracks are created. Cranks can be re nitrided but must be free of cracks in the nitride due being dropped, or from blow ups, unskilled grinding etc.. It is an expensive process, opinions differ about the extent and method of final finishing etc. The increase of diameter of main bearing journals a complication. For quality truck cranks etc a second light grind. Firms probably more familiar with now than in the past, when they often ruined.
Nitrided cranks are very hard and should not wear significantly, certainly not with white metal bearings.
I suspect all the crack testing and general mucking about could approach cost of a new one. Whether it can be made to run or not, put in an engine and sell as “Phoenix “ crank! Probably known to the sellers, I have been sold several dud ordinary Seven cranks in ages past.