I'm sure a competent machine shop can fix that.

Well sadly, I don't know how long the fresh pulley was loose.  I only noticed that the pulley was wobbly a year after the rebuild.  When I put a new pulley on, it wobbled as well.  I ran the DTI on the crank and it was out by 0.001.  I have been advised that the crank should be out of true no more than 0.0005.  Likely time for a new crank... ugh.

I have to say this sounds odd.

Thanks. I appreciate your suggestions.  I ran a DTI on the end of the crank and likely the crank is the issue.  The old pulley likely screwed up my crank, so looks like I'll be doing a teardown... ugh!

Thanks for the info. Take the pulley off and spin . Try to put something there like a dial indicator to see if your crank is wobbling. If that is true , look at the pulley.

Thanks for your note.  It was a complete rebuild.  Balanced crank, new bearings, etc.  I hardly have over 400 miles on it, so there's not been any real wear.

Yesterday I disassembled it all, and then check the measure on the crank and there was no wear.  I put on the pulley, and tapped it gently on before putting the crank bolt on, and spun the motor over a couple times and it was all looking perfectly true.  Then I torqued down the pulley and it went a bit wobbly.  Could it be the crank pulley bolt is slightly too long?  It's all quite strange.

Best,

Shawn

You say that you have a 66 Cooper S.. Cooper S crankshafts are kinda rare, were new bearings installed when you replaced the crankshaft? Balanced everything?