Crank pulley wobbling

[zboi]

Is it normal to have wobble in the crank pulley on these engines? There is maybe a 1/4" difference in the the space between the crank pulley and the timing indicator as I rotate the engine. I also see a slight wobble in the water pump pulley, it's probably closer to 1/16" though.

[NewZed]

Both of those are not right, but the damper is most wrong.  Damper rubber failure is not uncommon on these old engines.  The crank pulley is mounted on the damper, aka harmonic balancer.

 

https://www.rockauto.com/en/catalog/nissan,1976,280z,2.8l+l6,1209226,engine,harmonic+balancer,5512

 

[JMortensen]

Pull it off, check the end of the crank and the slot for the woodruff key. Pretty common for the slot to break. Happened to me.

[zboi]

I had pulled it off with a puller to do a timing chain job. Woodruff key fits very snug. I put a dial indicator on the pulley, it is perfectly centered, just 10 thousandths of pulley runout. Not trying to spend $300 on a new balancer. I guess I'll see if it's a problem when I get the engine running.

[NewZed]

If you pulled on the rim of the pulley you pulled on the rubber.  Might have damaged it.

 

10 thousandths is not 250 thousandths.  Not clear what your first post meant, with the 1/4 inch..  Anyway, if your timing marks seem off that's a sign of a failing damper also.  Good luck.

 

 

[zboi]

10 thousandth out of round, 1/4" deviation fore and aft 

[A to Z]

Better safe than sorry.

 

[NewZed]

On 9/10/2023 at 2:52 PM, zboi said:

1/4" difference in the the space between the crank pulley and the timing indicator as I rotate the engine.

 

Beside the fact that it's a sign that the damper rubber has been damaged and/or is failing, 1/4" will almost certainly throw belts at higher RPM.  I damaged a damper pulley on an old muscle car and it used to throw the power steering pump belt when doing typical high school kid stuff in the rain.  Pretty exciting, but it was a good arm workout when it happened.