Good day- I've noticed an issue with my engine that I hoped some of you good folks might be able to shed some light on. I am in the US, and have a 4JB1T in a Jeep CJ-7. I noticed a rattling sound coming from the front of the engine. Most of the issues stemmed from a bad bearing in the Chinese water pump I have on there. However, I also noticed that the v-belt accessory drive pulley appeared to be loose. I remove the 4 bolts and pulled the pulley off the crank. The center bolt on the crank appears to be tight, however the spacer behind it seems to be loose. (red arrow in image)
The 'toothed' timing belt pulley seems to be tight, but the spacer that the v-belt pulley bolts to has probably ~1-2mm of rotational play. Like a keyway or something is worn...
Question- What would cause this to loosen, and would there be any harm in removing the main bolt and putting a shim behind it to stop the pulley spacer from moving (yellow line in image)? I realize this would probably mean setting the timing, or at least putting the bolts in place to prevent timing from changing while i work on it.
I read some other posts alluding to a harmonic balancer 'slipping' causing the timing marks to be off, but I think what I have here is a separate issue.
Or should I just leave it be and not worry about it?
Thank you very much!!