1965 Buick Skylark Knock

[esetony]

have a 1965 skylark i just picked up and was told had a rod knock, before taking the engine out i want to be sure it is a rod knock. that being said it does sound like a knock except that looking at the crank pulley while engine is running it is incredibly wobbly. Is it possible that the harmonic balancer is bad, i am fairly convinced its a knock but just want to rule everything out since i have never encountered a crank pulley flapping around like this. thanks in advance for any help

[raycow]

The rubber-to-metal bond on the balancer can fail. To check, grab the outer ring and try to move it. In the case of a total bond failure, the ring can come completely off the hub.

However, a bad rod bearing is just as easy to check for. Disconnect the plug wires one at a time. When you reach the bad cylinder, if there is one, the knock will usually go away.

Way

[esetony]

would it cause the crank pulley to wobble if it was a knock

[raycow]

Well a bad rod bearing wouldn't cause the crank pulley to wobble, but right now you don't know for sure where the noise is coming from. That's why I suggested how to check the rod. You might not want to replace the balancer first and then find out that the bearing is bad too.

It all depends on how much work/money you want to put into the car. For example, if the bearing spun in the rod, you could have to replace the rod and get the crank ground. At that point, it might be cheaper to install a used engine than to do all the necessary repair work.

Ray