Re: engine vibration
yes, but that is still my point- static balancing with all the parts still will cause a vibration. This is because it is balanced to provide no rotation if mouned on an axle and left to sit- the shaft/flywheel will not rotate about its axis. Thats fine in a situation where the setup isn't rotating.
When you start to rotate, vibration may occur if the balance weights are not located to produce a net zero moment about the centre of the shaft. It's like having a shaft with a blob on the top at one end and a blob on the bottom at the other. As soon as the shaft begins to rotate, it will twist the mount in the dirction the blobs point... have a look at the diagram below. The shaft with red arrows is statically balanced but not dynamically. The two other shafts show two ways of dynamically balancing the shaft. Each shaft rotates around its axis (AROT) but the unbalanced one also attempts to rotate about the x (XROT). during AROT, the weights move, so the direction of XROT changes continuously. This causes a vibration.
The vibration will be quite sever at some speeds indicating a resonance. This is why wheel imbalance is often only detected at some speeds, especially high speeds. Flywheel imbalance is particularly destructive as it can create very severe loadings on the crank bearings and possibly a thrust force on the rod big end bearings which is highly undesirable.
1987 Jaguar Sovereign - Metallic Green
3.6L DOHC 24 Valve