I was about 100 miles from home in my 78 242 when I made a stop at a rest area. Car would not restart when I was ready to get back the road. It was the 10 year old timing belt. I had a spare belt and tools to fix it. Unfortunately, I forgot the B21 belt could be changed without loosening the pulley bolt. I used a breaker bar and loosened the bolt by bumping the starter. It was dark when
I got around to putting the spare belt on, but I had my free Harbor Freight
led flashlight. Put everything back on and tightened the pulley bolt. The
car ran well enough to get home but something was wrong. The next day I could
see the pulley was wobbling. The belt sprocket had not been in alignment with
the crank key when I tightened it. The sprocket was jammed and wouldn't come off. Had to wedge a long chisel behind the sprocket and keep hammering until it came off. Fortunately, the sprocket is fairly soft and didn't crack, but there was damage from the misalignment and hammering. Had to do a lot of filing to get the sprocket cleaned up. Put it back together right and it's still running. B21s can take a lot of abuse.