Rebuilt Engine bearing wear

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Do you by chance have a windage tray? I thought I had a knock in a 360 once (new build) and it turned out the front crank counterweight was kissing the tray.
 
6PakBee said:
Do you by chance have a windage tray? I thought I had a knock in a 360 once (new build) and it turned out the front crank counterweight was kissing the tray.
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Not that I'm aware of. Unfortunately it's definitely an actual issue. Noise goes away completely with cylinder 2 not firing... damn
 
Ok, what’s the background on the pistons and bores. New pistons? Bores honed, bored, surface prepped? What’s the piston to bore clearance? What’s the piston? Forged? Cast? Hyper? By the looks of those bearings, as stated before. They show no signs of distress. You have ID’ed the cylinder, ok, but it could be a piston issue. It’s a dull thud? History of the rods? Rod side clearance? At this point you can’t trust anything you haven’t personally checked.
 
furrystump said:
Ok, what’s the background on the pistons and bores. New pistons? Bores honed, bored, surface prepped? What’s the piston to bore clearance? What’s the piston? Forged? Cast? Hyper? By the looks of those bearings, as stated before. They show no signs of distress. You have ID’ed the cylinder, ok, but it could be a piston issue. It’s a dull thud? History of the rods? Rod side clearance? At this point you can’t trust anything you haven’t personally checked.
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Pistons are brand new standard pistons. They are hypereutectic. The machine shop measured the bores and conformed they were in spec. They were honed. The noise can be easily heard using a stethoscope on the OPPOSITE side of cylinder 2 on the oil pan. I can't hear the noise if I put the stethoscope on the oil pan on the side of cylinder 2. Noise is a rhythmic knock. Revs up with motor but does not get louder. In fact you can't really hear it much when revved. I do not know the history of the rods or the rod side clearance. It did this on the first start of the engine but went away. Which stumps the machinist and myself.
 
I'd still like to know what the actual oil pressure is (with a known good live gauge) both cold and hot.
 
Dipstick hitting the crankshaft, tick goes away turning dipstick 180°??

Trucks had longer dipsticks that ran to the sump in a side tray/tube??

Pull the dipstick, see if it goes away??

Process of Elimination
 
Borescope, have a look into #2 cylinder to look for any wall scoring.


Press fit wrist pins??
 
Years ago I had a noise problem pretty much like yours, I just could not find the issue. I have decided to tear it apart and triple check everything. It was pure luck while removing one of the pistons and dropping it on the bench and heard an every so slight click. I found one of the steel struts cast into the piston was loose and making the infamous clicking noise. It maybe something to look for if you decide to look deeper into your engine noise.

AUTOTHERMIK® / HYDROTHERMIK® pistons have cast steel strips and are slotted at the transition from the ring area to the skirt area. These pistons run very smoothly and are preferred for installation in car engines <<<<<< from Melling's Web Site

piston steel strut.jpg


piston steel strut 2.jpg
 
Braeden Clark said:
That's a good idea. Almost 90% positive it's cylinder 1 but I can narrow it. But I don't know why it's knocking... its got fresh bearings the were plastigaged. Only thing I can think is the crank is out of round. Idk. Kinda discouraging.
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Just going to throw this out there but I had a slant 6 that several experienced mechanics thought had a rod knocking. After pulling the engine turns out the flexplate was cracked.
 
mgoblue9798 said:
Just going to throw this out there but I had a slant 6 that several experienced mechanics thought had a rod knocking. After pulling the engine turns out the flexplate was cracked.
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That noise wouldn't change by killing a cylinder though.....
 
I would be checking the oil hole in the #2 rod crank journal.....for a blockage.
 
Braeden Clark said:
Pulled injector wire on cylinder 2. Noise changes.
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Braeden Clark said:
. But that doesn't make sense since it goes away when u unplug cylinder 2.
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Preface this by saying i know little about F.I. Any chance a bad/misfiring injector on that cylinder could cause spark knock? What does the plug look like compared to the others? Just a wild guess.
 
How about pulling the spark plug wires instead of the injector wires to see if the knock goes away?
 
OldmanRick said:
Preface this by saying i know little about F.I. Any chance a bad/misfiring injector on that cylinder could cause spark knock? What does the plug look like compared to the others? Just a wild guess.
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Spark plug looks the same as the one next to it. Looks clean.
 
That pretty much narrows it down to that cylinder. It's going to be a bad or wrong sized bearing, Loose rod studs/nuts, no oil to that bearing, bad wrist pin and/or bushing, cracked piston, piston slap due to too much cylinder wall clearance, etc.
 
cudamark said:
That pretty much narrows it down to that cylinder. It's going to be a bad or wrong sized bearing, Loose rod studs/nuts, no oil to that bearing, bad wrist pin and/or bushing, cracked piston, piston slap due to too much cylinder wall clearance, etc.
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It's got to be something wrong with the bearing or rod I think. Only thing I messed with was the bearing. Same cylinder made the same noise when this engine was fresh... the ONLY thing that the machine didn't check was the roundness of the rod. He may have even done that. Just didnt ask. He said he check the roundness of the crank. I just can't see why it would start knocking with fresh bearings... and the fact the same cylinder did this earlier but it went away has me lost. I'm gonna have to drop the pan again... which is actually simple. I'm just sick of this engine.
 
Are the valve reliefs the same size on these pistons? OEM style are sometimes. Aftermarket the intake reliefs are bigger. Could he have the piston in the wrong hole? That sound is more of a ringing ping sound though.
 
furrystump said:
Are the valve reliefs the same size on these pistons? OEM style are sometimes. Aftermarket the intake reliefs are bigger. Could he have the piston in the wrong hole? That sound is more of a ringing ping sound though.
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Ok so here is an update along with videos. The first video is about 5 minutes after I started it up with fresh rod bearings. The second video was taken yesterday with the engine fully warm after 30 minutes of driving. The noise has gone away pretty much fully. Might be a tiny tap but I can't hear it anymore. I know rod knock doesn't go away but this noise sure gets better with time and it only does it with fresh rod bearings

https://youtube.com/shorts/-UDRWe-fyCc?feature=share

https://youtube.com/shorts/yIlaI3M1QSo?feature=share
 
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CFD244 said:
That's bizarre??
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Yep. Nobody I've talked to can make sense of it. It was definitely a hard, rhythmic knock. But it went away. Almost no bottom end nosie should go away like that. Definitely heard loudest in the oil pan. Definitely cylinder 2. At least it's gone now
 
Braeden Clark said:
Ok so here is an update along with videos. The first video is about 5 minutes after I started it up with fresh rod bearings. The second video was taken yesterday with the engine fully warm after 30 minutes of driving. The noise has gone away pretty much fully. Might be a tiny tap but I can't hear it anymore. I know rod knock doesn't go away but this noise sure gets better with time and it only does it with fresh rod bearings

https://youtube.com/shorts/-UDRWe-fyCc?feature=share

https://youtube.com/shorts/yIlaI3M1QSo?feature=share
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The first sound didn't sound ANYTHING like a rod knock to me
 
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