Engine Out of Balance?

[trevor'72]

It is possible that the balance has changed it's balance. I'd buy a new 28oz imbalance and put it on. See what happens. Sometimes the ruber peice that's between the two metal parts will shift causing the wieght to be moved in relation to the other balanced parts. This would cause a vibration, and if not repaired it could be very costly. Oil pumps crack and stop working, and cracks in the block form usually first allong the pan rail. A way to see if this is FOR SURE the problem is to check the timing. My stock balancer after rebuild was found to be 1degree retarded. To check put the engine at TDC #1 (top dead center for cylinder #1) and wee what the timing pointer is pointed at. It sound be zero. But remember that the crank makes 2 turns for every 1 turn of the cam, soo it must be on the compresion stroke. To make sure it is the compression stroke, hold a finger/thumb over the spark plug hole after removing the spark plug and coil wire. DO NOT PUT YOUR FINGER/THUMB IN THE SPARK PLUG HOLE!!!!! Simply hold it over the hole. Have someone bump the starter or turn the balancer (a braker bar and socket makes this easier). When the pressure from that cylinder making compresion pushes your finger away it will be close to TDC #1. Make minor adjustments to make sure it is as exact as possible to TDC. Now look at the pointer. If it points to 0 you're balancer is fine. Unless it made one complete ratation which is highly unlikely because the balancer would have split in half and fallen apart by now.

have fun.