Rattle after rebuild

Found out my last block had a crack in cylinder #6 [http://www.earlycj5.com/forums/showthread.php?t=86284], replaced the block, put everything together. Now at anything around ~ 1500-3k RPM [no tach] I'm getting a rattle from the passenger side. It sounds like it's from the block rather than the heads. Looking for some help on process of elimination:

Pistons - new
Connecting rods - from the damaged motor, did not check bearing surface diameter.
Rod bearings - new
Crankshaft - measured within spec
Main bearings - new


It does not sound like valve train hitting the pistons.
Removing individual spark plugs makes no difference, so it's not knock
The pistons & rods with their old bearings & crank made no noise prior to block replacement. I used the block & crankshaft from the donor engine, new main & connecting rod bearings, now I have the rattle.

Theory:
The connecting rods were damaged while the pistons were beating a bolt into the cylinder heads. This 'damage' took the form of an out of round bearing surface. I don't see what else it could possibly be.

 

is the noise constant and the same regardless of acceleration, hold steady, and de-acceleration?

I'd suggest listening with a long handled screwdriver or other listening device to try and narrow it down:
left side
right side
valve train
deep inside bolck
etc

 

It's from the passenger side block. Around #4 but couldn't narrow it down with a pipe or breaker bar beyond that.

Noise is constant when held. Changes while revved but seemed to quiet down at higher rpm. Haven't pushed the engine though.

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I think I would drop the pan and take a looksee.
Less labor than pulling the head back off.

 

If the block has been sleeved the sleeve could be lose. I had one do that. When the engine warms up the sleeve will expand and the rattle will go away. Its not a good thing. Good Luck!

 

Took a video of how it sounds warmed up. When the block is cold, the engine only made the noise for 2 seconds at start up; however, was still quite 'noisy' when revved. The clattering noise became more pronounced only when revved & warmed up.

Video starts at idle, jumps in RPM then held, jumps in RPM soon after camera reposition, then throttle let off.

http://www.youtube.com/watch?v=bV6OKE0Uj-M

Oil pressure light is not on, so I believe it's high enough.

What would I look for when pulling off the oil pan? I just assembled everything on an engine stand and torqued it appropriately so that nothing was loose. The only way I've found to determine if it's a bad rod bearing surface would be to use plastiguage which i have no experience with.

The old connecting rods had bearings that were for a .03" under crankshaft, I used new OEM size bearings with the crankshaft that came with the block. Several of the old bearings had copper showing so were worn down pretty well after only 3k miles. That quick wear could have been from distorted rods.

Either way I know I'll be taking things apart... AGAIN. So trying to figure out exactly how to diagnose something that only happens when under high RPM load.

 

to check the rods and mains
should be something showing by now

 

Sounds like total catastrophic rebuild failure on my part. Fantastic. I don't understand how the bearings can be off so far. I'll compare new part numbers to old but the crankshaft journals were only off OEM specs by .003". I'll just order some .01" under bearings for my other crankshaft and swap that in with new bearings, I know those worked at least. Thanks everyone for the help. Off to the garage to remove this thing for the... 4th time *hangs head in shame*

The main reason I'm assuming it's all in the crank is due to the main & connecting rod bearing noise that people have mentioned. I'll still try and measure the connecting rod journal diameter to verify they haven't stretched.

 

Got down to the short block last night. The pistons had enough movement to hit the #2 spark plug and take away any gap while it was running so that's probably the one that was the noise. I can't get any of the pistons or crank to move any noticeable difference. Last night most of my dreams were about a bright yellow Jeep on fire so I guess it's time to give up.

Going to take the short block to a local machine shop and have them properly assemble the bottom end. I've got a spare crank that was already machined down 0.01" and will let them verify all clearances. I measured any surfaces I could and found things within spec, everything was torqued correctly, but I obviously mismeasured something. Thanks for the help everyone. I'll be sure to get a copy of the measurements they come up with for comparison's sake.

 

Autolite #85 gapped to 0.04" for HEI distributor.

 

Pistons have no protrusion above the block & have a deep dish in the center area. I couldn't figure out how that much slop could have been in #2. Perhaps they head was set down with the plugs in?

 

Just wanted to post an update. The machine shop says everything was within spec except for the connecting rod journals. 2 only had 0.001" of clearance, so they are honing those out. The rest were at least 0.002-004" out of tolerance, at $18 ea to have them remachined, I figured I'll just do that than buy new ones. Should take care of all the issues and be up and running by this weekend... ha ha ha ha ha ha no, not counting my chickens before they've hatched... again.