Re: Micro Welding of bearing shell to rod housing bore
 

The caps have dowels and the mating surface looks perfect. The upper shell is always not as tight as the cap shell in its bore.

Is there a certain finish that the bore needs to “hold” the bearings?

Re: Micro Welding of bearing shell to rod housing bore
 

I've been reading this thread and wondered why no one mentioned detonation as being a possible issue.

It can show up in rod bearings....

Usually the shells just fall out....and might have some odd looking wear marks....

Re: Micro Welding of bearing shell to rod housing bore
 

If the problem didn't exist, and now it does, something happened. I've seen upper bearing shells beat up to the point they just fall out of the rod.

Fly poop on spark plugs? Fuel change? Verify timing and TDC marks? Try another known good timing light?

Just reaching here.

Re: Micro Welding of bearing shell to rod housing bore
 

or cam change too!

Re: Micro Welding of bearing shell to rod housing bore
 

First noticed it when we started getting close to the 590 hp number. Damper is on TDC, fuel seems to make no difference c11, c12, c10, renegade 116. cam changed made no difference.

Re: Micro Welding of bearing shell to rod housing bore
 

If the engine is apart and obviously it is....

Look at the ring lands and the tops of the pistons for any oddball signs that usually indicate detonation. Pecker tracks on pistons, or on the sides of the pistons above the rings. Ring lands beat up....

If all is clean then you can rule it out....

It's not likely but I thought I'd throw it out there.

Re: Micro Welding of bearing shell to rod housing bore
 

Just thinking out of the box, how old is the Harmonic Balancer?

Re: Micro Welding of bearing shell to rod housing bore
 

At least 6 to 8 years old. Last time it was down I had crank checked for balance it was ok

Re: Micro Welding of bearing shell to rod housing bore
 

What brand of balancer are you using?

Re: Micro Welding of bearing shell to rod housing bore
 

A good read on honing the big end of steel rods is in the SA Design Jenkins small block Chevy book I’d how he puts .002 shim stock the hens the rods round then removes it. The rod is now out of round but high rpm it stretch’s back round as I remember it’s when the rod does not have enough material at the parting line.