conrod tracking

[david.anderson]

I have a VH bigend bearing in which the conrod has tracked badly to one side. When I spin the flywheels after centering the conrod it tracks to the side within a few turns. I have checked the conrod and it is straight. The flywheels have a total runout of .001” with about .0005” runout per shaft. Does anyone have any idea what the problem is or is it simply in the bigend itself. The bigend was originally from AOMCC. Thanks
David

[Simon.Gardiner]

David
I can only refer to 'Tuning for Speed' (Chapter 1, 'A Preliminary Survey'):
'...another (point which needs to be watched closely) is whether the rod or cage shows any tendency to work over to one side and bear heavily against the flywheel. The latter state is a sign that the roller-cage slots are not absolutely parallel with the axis. If all the slots have been incorrectly machined at the same small angle the rollers will clearly tend to screw their way to one side, though if they are out of parallel in random directions the errors may all cancel out.'
It seems to fit your description of the problem.

SG

[nevhunter]

The rollers have to have some play. Min.0008". Too tight and they will wind to one side. Another possibility is conrod not on centre, or bent. Nev