Harmonic Balancer Shakes - Should I not drive the car

[Peabody]

Hi - I am the original owner of my 1990 S13 with 180,000 miles. For the last 5000 miles I have heard the timing chain rattle on start up and plan to fix that.The other day I did a tune up and I was setting my timing and I could not find the marks. My friend came over and told me that all the pullys, Harmonic balancer had a bad shake or wobble to them. When I have it gas they seem to turn fine but he said it was my mind playing with me and they were still shaking. He said the balancer moved 180 degrees and that is why the timing marks are not lighting up where they should and I can see the marks if I shine the timing light from under the car at the marks. At this time I cannot afford someone to fix the timing chain and the balancer and want to know if I am at risk of damaging the motor if I still drive the car in it's condition maybe 100 miles a week? I know when I have the chain replaced all the pullys come off so to replace the balancer at that time should not increase the labor. I am going to check for prices and want to know a ballpark on the repairs needed. And also more important if I should not drive the car or maybe if I just baby it. I have lived with the chain rattle for years so I am more worried if the balancer can do damage.

THANKS