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Had a nightmare on my "rebuilt" J engine and discovered I had a welded/twisted crank. Got a used crank, confirmed straight, and had it welded. Installed in the original crankcase and found out while checking endplay that the case halves no longer hold the crank bearing outer races tight. To the extent that it oblonged the dowel pin hole in the upper case at the thrust bearing. Looks like the excessive runout from the bad crank stretched the bearing bore/journals.

Got a used case, torqued to specs, and confirmed the bearings are held tight. But I now noticed a tight spot while rotating the crank by hand, like every 3rd or 4th rotation. And when it get's tight I can no longer check the endplay without prying with a screwdriver.

Just finished double checking the crank. Confirmed index by installing the block with #1 and #4 pistons and comparing piston deck clearance at TDC. The were dead on at almost zero (flush).

Then I checked runout. Didn't have thin enough V blocks so I took off the outer bearing races and laid the crank in the bottom case half, this way it's supported at #2 and #5 bearings just like with the V-blocks. Max runout was about .0025", Well within specs.

So I'm assuming It's the case (journals not inline), but don't know if I should get another one. Anybody see this before? Wondering if the case isn't perfect because it was apart and sitting around. And maybe the crank will settle in after some runtime.

Did the cases come as a matched set upper and lower, I know mixing isn't the preferred method although some get away with it.

One of the major players in the crank building world does line boring or used too, Person or Gardener you could contact them and get advice.

NOW what I am about to say may seem crazy and is possibly not doable for the average guy at all I know I would find this hard to do , oven size/ wife/ scary!!
This is just stuff I have picked up along the way and in no way do I want anyone here to think I am totally nuts…but it OK if you do!!

Get a piece of bar stock turned to the o.d. of the crank bearing , you will have to pull the locating pins and/or machine the bar stock to accept them, bolt it into the cases wit the proper torque setting and bake it at about 500 deg, get the cases to that temp and then shut it down and let it in the oven until cool.
I know a guy who has a wicked triple who modded it to case reeds and had to do this to get the cases back in shape , he had the same problem, tighten the crank up and then a tight spot, after he was done it spun with one finger. I dont know what he did with the tranny area if he had to put spacers in there also.

Sounds like a good idea, but definitely don't have a big enough oven. It's a slight tight spot, not like you have to put a wrench on it or anything. I'm wondering if engine heat may accomplish the same thing.

Yes. Upper, lower and main cap are a match from a KZ1100 shaft. And there doesn't seem to be any issue with the trans since the shafts use only two outer bearings.

Could be the crank itself. It occurred to me but didn't think about trying the 750 one. May not have mattered being I had run it so long. When I put it together and heard squealing, I thought it was a crank bearing. Turned out it was the rotor spacer. All's quiet now.
Steve

I can't see it being the crank with runout in specs. All bearings look good and feel smooth as glass while turning, and the crank spins freely until torqued down.

You know it might fit in my oven. I could completely bolt it together with the crank and heat it to normal operating temp (200-250F) while spinning the crank periodically. And see if it frees up.

Jeff was telling me we could heat up my swing arm to 500* with a "rose tip" and clamp it down to get the 1/8" twist out of it then let it cool down slowly. Same principal. I don't think I'd want to heat up a crank like that. If you put it in the oven even at 250, I'd think it would bake the oil residue and cause even more problems. Maybe we're overthinking this.
Steve

I'm just gonna bolt it together and let it sit for a week right now.

I installed the crank and torqued just the main bolts and Let it sit overnight. Took it apart just now, installed the trans, and bolted it together with all bolts. Now no matter how many times I spin it can't find a tight spot. Think it was just out a little from sitting split.

I guess that could be. I've decided to buy the APE main bearing bolts. I already have 4 hardened bolts and like to torque the others more. Looks like I can install them with the pan off. I might be hearing the chattering again.
Steve

On mine two of the main cap bolts you can't get to without splitting the case. When are you hearing the noise?

Idle. The main cap has 12.9's on them. Might be the rotor again.
Steve