bad rod bearing tests.
 

Still looking for clicking noise like flex plate hitting something as posted on another thread called ' cracked flex plate but not cracked '. I,ve removed the oil pan thinking the oil pan baffle had come loose and hitting crank but nothing. Oil pan looks clean , don,t see any burn marks on rods and can,t wiggle any caps up and down but can wiggle sideways abit and have read that is normal. I only get the noise when running , but with coil disconnected and cranking motor over I can,t get no noise. Torque disconnected and no pulleys on. Would I hear rod knock with just cranking motor over with oil pan off ? Could the oil pump make this noise even thou I have great oil pressure ? I think I might have to go back to valve train and look harder. I,ve done everything if you want to read other thread. Engine has maybe 8000 miles on a rebuild from a shop.

Re: bad rod bearing tests.
 

I had an engine with standard rod bearings on a 0.010 under crank. It's pitch was a thud thud thud like a rod bearing, but at a really fast repeat rate, like rocker noise.

Here's how I diagnosed it:
When I had 10W-30 in it, it was always thud thud thud. When I put 15W-40 DELO oil in it AND it was cold, it was quiet. When it warmed up, the thud thud thud noise started again.

It wasn't until I had the engine out for a rebuild that I was able to confirm it.
As you observed, they all wiggle sideways, but mine also wiggled in the direction of rotation. Once I pulled the caps, miked the rod journals, and read the STD on the backs of the bearing shells, I knew what was going on.

I was amused and annoyed that someone would do that.
Buy, hey, we all have to learn somewhere.
Maybe it was some guy's first motor.

Re: bad rod bearing tests.
 

The way to get a definite answer is with Plastigage. It's inexpensive and doesn't require you to disassemble the engine. Since you have access to the caps, it should be really easy. Any auto parts store should have it in stock.

Re: bad rod bearing tests.
 

Thanks. I cranked it over for 5 seconds with spark plugs out and didn,t hear nothing. I feel like I,m chasing my tail. I have a long 2 bay garage , so I,m trying to finish some cosmetic things on my Blazer and then I can switch Blazer for truck and pull engine if I have to. I,ll try the plastigage ,have used it before. Should have bought the house across the street, it has a double lot but it was only 800 sq. ft. house with no basement.Lots of room for a 3 bay to get away from the wife LOL, no really

Re: bad rod bearing tests.
 

Hello, I don't know if this will help but I had a lifter noise that was from the fuel pump rod. I didn't read your other post and it looks like your looking for a rod noise.

Re: bad rod bearing tests.
 

thanks did check that awhile ago. I,m tired of playing with it so I,ve decided get the blazer ready and then move truck in and take engine out and have a look . Lot easier ,I thought it was something simple but unforgently every thing in a engine can make this noise and I can,t pin point it so I,m going to get Jessica Fletcher to look at it. Looks like Murder. She can solve every thing

Re: bad rod bearing tests.
 

Pull the oil filter and cut it open to check for any metal in the pleats.

Re: bad rod bearing tests.
 

cut the filter open already, not a spec but I change oil every year