possible causes of "rod knock" noise

89supra7mgte

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Sep 20, 2009
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Was running a gt40r turbo that blew the thrust bearing causing low oil level. Could only hear knock sound at 3k no load, never loaded it didnt want to make matters worse. pulled engine, dropped pan found that some bearings were scarred up, nothing on journals or rods. pistons were not loose in cylinders, no rod moverment on wrist pin. installed new standard size bearings (rods and mains) all seem to be in spec. oil pressure was never unusually low. is there anything else i chould check before reinstalling
 

CyFi6

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Make sure you check all your clearances before just tossing it together with new std bearings, at least plastigague them. It is still a risk though considering any bearing material that came off the bearings could now be in any/all of the oil passages only to hit the brand new bearings and damage them.
 

CyFi6

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I guess I am just not understanding what you are getting at, not sure why you have to shake your head at everything, perhaps we are not all extremely brilliant. Just because it is the tech section doesn't mean that we don't have room to learn. You said that metal crap wont reach the oil cooler and lines unless the filter went into bypass, which doesn't make sense to me because oil goes through the cooler bypass and through the cooler before it ever reaches the filter, therefore any contaminants in the sump can be fed directly to the cooler without even seeing the filter.

The only thing i can assume you are getting at is the fact that if the filter went into bypass, it would be circulating contaminated oil to the bearings and accelerating wear, but that doesn't mean there wasn't crap in the sump to begin with to get in the cooler.

Also who is to say that contaminants didn't plug up the filter and send it into bypass mode?
 

IJ.

Grumpy Old Man
Mar 30, 2005
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I come from a land down under
Never owned a GTE Adaptor ALL of my engines always got a full flow cooler set up so wasn't aware that's how Toyota plumbed it...

I retract my earlier post and have to agree a full flush is very important on EVERY single build not just after a failure.

I was talking about the Filter bypass, by rights it shouldn't ever bypass in a GTE due to the multiple leaks and reliefs in the system.

In my defence the GE Hot Climates Bypass Cooler IS plumbed into the main gallery after the filter.
 

Poodles

I play with fire
Jul 22, 2006
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Shouldn't really matter for the simple fact the cooler drains to the pan. Anything that actually get put through the engine goes through the filter.

Filter bypass doesn't happen easy either, it's more of a burst protection for the oil filter (and not likely to happen on our motors).
 

89supra7mgte

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Sep 20, 2009
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ok.... well this thread went way off topic but always good to know for future reference.

i did check all clearences and they are within spec. number 5 rod has some side to side movement that you can hear but is still within spec.... could that have been what i was hearing? when i started pulling it apart i found that the compressor wheel was hitting the housing could that have been making some noise passing through engine some how?
 

GrimJack

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Compressor wheel is possible, but I wouldn't rank it very high... usually that thing is spinning so damn fast that any kind of interference sounds like a high pitched whine.

The other common causes of rod knock like sounds are loose bits - specifically the flex plate / flywheel or front main damper pulley.