Same rod bearing spun... Why?

[2g2ner86]

I spun a rod bearing on my first motor. And now I just spun another one on my new motor and it's the same cylinder. It's the second one in from the left looking down at the top of the motor. Why does it only happen to that one? And all the other bearings look brand new! Please help.

 

[LiquidX]

Same crank?

That would be #2. #1 cylinder is closest to timing belt and #4 is the furthest away.

 

[2g2ner86]

Then it is #3 cylinder and it's a whole different motor all together.

 

[2slow4now]

Did you use the internals from the old motor? Rods, crank? Oil clearances all checked? If you reused the rods it may have been out of round. That would make a tight spot on the bearing so even if you plastigaged it you would never know.

 

[burningforce]

It's really hard to say but for failure to happen on the same cylinder is kinda weird. How was the oil pressure? Did you use the same oil pump? A combination of things can cause spun rod bearing failure like over revving or simply just running your car hard when engine is cold and etc.

 

[2g2ner86]

I pulled a motor out of a running car I had and it only had 65k on it. So everything on the inside of the old motor was set aside. The other motor had nothing from the old one on the inside. But I did use the same oil pump.

 

[LiquidX]

Sorry, I misread the left for a right.

If nothing was re used from the old motor internally the. It may just be a coincidence. These is a 25% chance to spin the same bearing off the rods.

Oil pump won't make a difference as everything is getting oil as it should. The crank receives oil first and then the head.

Unless the pump wasn't fully cleaned of possible shavings that would attribute to it.

 

[donniekak]

Using the same oil pump, or any other component from a spun bearing engine, without cleaning it completely with brake cleaner, will put all of the old bearing material in the oil system.

 

[importracr317]

Using the same oil pump, or any other component from a spun bearing engine, without cleaning it completely with brake cleaner, will put all of the old bearing material in the oil system.

+1. That crap gets EVERYWHERE. I just got done with a turbo rebuild because, as Justin said, "the rod bearing material literally sandblasted the journal bearings of the turbo".

Not saying that's the reason for your 2nd spun bearing, but IMHO, it's highly likely. It's best to use all new parts (including the oil pump) after rebuilding a motor with a spun bearing.

 

[DSM4LlFE]

Sorry, I misread the left for a right.

If nothing was re used from the old motor internally the. It may just be a coincidence. These is a 25% chance to spin the same bearing off the rods.

Oil pump won't make a difference as everything is getting oil as it should. The crank receives oil first and then the head.

Unless the pump wasn't fully cleaned of possible shavings that would attribute to it.

 

[DSM4LlFE]

This happen to mine. Turned out to be the tune. The third fuel injector wad staying open longer washing out the cylinder wall. Then going pass the piston to the bearing. The smelled straight like gas.

 

[motomattx]

Knocking in that cylinder from a lean condition or too much timing can cause that.

 

[BogusSVO]

How long was the 2nd motor set up before installed and fired up?

 

[streetraceboi]

Holy thread revival