4.0L OHV Mystery Knock after Rebuild

[broncc]

Hello all...

Long story short I had to put a reman crankshaft in my 4.0. When I started it back up it was knocking! I have it back apart now and I'm properly stumped. The rods all measure perfect 0.0015 clearance with my 10 under bearings. It sounded like it was coming from the bottom when it happened. I'm going to pull the first three main caps tomorrow.

Does anyone have advice or experience with what it could be? I'm running out of ideas and I'm not sure it was a collapsed lifter. I don't recall it sounding like one and I'd rather not pull the top end apart to see if lifters that have been sitting for a long time are pumped up.

 

[Uncle Gump]

Without hearing it...

Plasti-gage it.

Did it have good oil pressure?

Flywheel got torqued?

No beat up marks on the rod bearings?

 

[broncc]

Bearings came out looking brand new. Plastigagued to 0.0015. All flywheel bolts seemed tight. I recall oil pressure being fine.

Even gave it a little rev back before parking it out of frustration.

 

[Uncle Gump]

End play good?

Did you do cam and lifters when ya did the crank?

 

[broncc]

Crank endplay is within spec. Rod bearing end play was not mesured but seemed fine. Camshaft and lifters are original with the motor and were not giving trouble before this.

I'm going to see if I can verify the timing chain tensioner that I replaced a while ago survived the rebuild. I'm pretty sure I got the timing right because it ran nice while knocking. Point the two dots at each other like a small block.