Threads on this type of subject are becoming interesting again. With diesel now at $4/gal and talk of it going to $5-6 by mid summer. If nothing else, it will probably be time for me to re-install my waste oil shop heater for next winter, as Nat gas is getting pricey too.

Glad to hear it! Actually diesels are meant to be loaded all the time, and glazing can occur at any time when they are
run lightly loaded or idled excessively. Your rig sounds mighty fine!

I added a generous amount of silver solder around the bung to strengthen that area. A coat of paint, and it's looking much better. It runs well and starts up easily now, I think the lucas treatment and ATF I put in the fuel helped a lot. Took the ST head partly apart and ordered new bearings and brushes as the bearings are growly and the brushes are stuck in their holders. I'll probably have to bash them out.

A short video...
https://www.youtube.com/watch?v=rOgIELxKVUo

 

Never ordered from Aliexpress, skeptical. I've seen some things on there of interest, (more of a wholesale industrial nature) but when I've sent an inquiry I've never heard anything back.

WOW !! 

Lucky that you stripped it down.
After a good cleanup and re-assembly it should be a good runner.
As mobileBob noted, parts are available easily for these engines.
AliExpress has lots of parts at good prices.

Now for the good news.  I don't think the slip rings will need to be investigated after you see these pics Bob.
Super lucky the sand apparently didn't make it into the oil passages and thru the bearings.....yet.
I am so glad I took the pan off! A bit of silver solder will repair the crack.

I don't know what the cam lobes and rod inserts might look like with 'hours' run time on them, but these don't seem to have much time at all.

Some rust in the cylinder below the ring travel........

Revolting developments and a sign from.......someplace?

Yesterday I ran the engine a bit as I said, and it started much easier. Run time maybe 10 minutes total.
I noticed a drip from under the oil pan the day before, and now again after just a bit of temp build up, it's dripping slowly again. Luckily, I'm able to pick it up high with the forklift and check the underside. I suspected the seal on the drain plug, so took it off. The rubber O ring (such as it is) was mashed flat and cracked. I installed a new one, and snugged the drain plug. Re-installed the oil.  More dripping.......!  So once again, I hoisted it up and got underneath for a really up close look. It was then I noticed the dent on the corner of the oil pan. And separately, nothing to do with the dent, I discovered a tiny crack in the pan under the drain plug. Crap!  But.....it gets better!

I drained the oil again last night. And I spent a lot of time thinking (when I should have been sleeping) about an approach to the problem. I did consider JB weld, but I wouldn't feel right about that. Today I picked it up from the handle above so no  forks interfering below. And I see the pan is not obstructed by the frame work. So I removed the pan bolts......

And here is where the horror show begins. But with a silver lining!
I half expected to see some.....SOME...... sludge in the pan, but nothing like this!  Not only was there about 1" of sludge, there was also a generous heaping helping of Foundry Sand. And the pick up screen was in-bedded in it and it seems about completely plugged. I have no idea how the oil pressure indicator was showing pressure.
It's hard for me to believe with this amount of sand, that this was anything other than deliberate. And this is a Changfa not a Listeroid.
As you can see from the pics, I was very relieved to see the important parts undamaged from sand and lack of oil. Somehow, it seems the tiny crack and annoying oil leak was a blatant cry (cry, dripping oil, crying tears, pun intended)  from the engine to implore me to remove the pan and rescue it from certain death.

+ to the slip ring closest to the windings..........got it.
Thanks.

This wiring diagram should work.

https://www.utterpower.com/wp-content/uploads/2010/07/Figure1.gif

The rings need to seat....if that's what is causing the smoke. Warm it up again, then apply a 50% load to it for  15 minutes.
Then go to 70% load for 30-45 minutes and see if the smoke diminishes. Let it cool down cold, and do another 30 minute run at 70%. Might take longer but running new rings on new cylinder wall unloaded is asking for glazed cylinder that may always smoke. 

Of course there are other questions:
Is the piston/cylinder clearance correct?
Ring gap right and gaps staggered?
Cylinder round and no taper?
Correct cross hatch pattern from the hone?