26-09-2019, 03:18 AM
(This post was last modified: 26-09-2019, 03:20 AM by Bob Culver.)
The common jigs utilise the gudgeon in the V block for basic alignment. Assumes the rod not seriously bent.
In my expereince of Seven and Javelin cranks the ring test means little unless very fractured. (Risky applied to Phoenix as if dropped on end likely to crack the protective nitride!)
The topic of crack testing has been covered on Forum, under both cranks and steering arms. Search should find most.
Commercial firms use powerful magnets, fluid and ultra violet lamp.
Forum users report success with home kits utilisng a magnet.
Based on camparisons, I am sceptical of the penetrant only without magnet ones. Many kits have a shelf life.
Start at the rear journal and work forward , checking esp the internal radii. If OK check the oil holes. If an original crank and still OK , check method!!
Others have reported propensity of rods to crack as an extension of the gudgeeon bolt slit. Gudgeon pin fit and bolt thread important.)
Failing big ends often show a sort of spangle pattern at an early stage as sections start to lift.
In my expereince of Seven and Javelin cranks the ring test means little unless very fractured. (Risky applied to Phoenix as if dropped on end likely to crack the protective nitride!)
The topic of crack testing has been covered on Forum, under both cranks and steering arms. Search should find most.
Commercial firms use powerful magnets, fluid and ultra violet lamp.
Forum users report success with home kits utilisng a magnet.
Based on camparisons, I am sceptical of the penetrant only without magnet ones. Many kits have a shelf life.
Start at the rear journal and work forward , checking esp the internal radii. If OK check the oil holes. If an original crank and still OK , check method!!
Others have reported propensity of rods to crack as an extension of the gudgeeon bolt slit. Gudgeon pin fit and bolt thread important.)
Failing big ends often show a sort of spangle pattern at an early stage as sections start to lift.