AngryBaconMan

TLDR at the bottom.

Some quick back story. I bought this car back in November and fully rebuilt the engine. Almost everything is new or has been worked on. New pistons, rods, rings, bearings, new crank, oil pump, springs/retainers, and every seal or gasket along the way. I had the engine bored out 20 thou (.5mm) so the cylinders are perfect, and I bought oversized pistons to match. I fully rebuilt the trans as well, new synchros, bearings, seals, and synchro hub sleeves. I could go on to list about 100 other things I've worked on.

500km into driving the car I start getting this squeaking sound, especially at idle and ONLY when its hot. When its cold, nothing.

I've removed the AC, Alternator, and PS belts, and it persists. It really sounded like it was coming from the oil pump, I took it off and inspected it to find score marks and scratches inside of it. Thinking that was my problem I replaced it, only for it to happen again after installing a brand new one.

I've had an oil pressure gauge right from first startup and it's always been 80-90psi cold and then 15-20 psi when hot at idle. I've pulled spark on each of the cylinders one at a time and it doesn't seem to change the sound at all. So I highly doubt it would be any of the rod bearings.

It still sounds loudest right from the oil pump/harmonic balancer area. I've tried gently tapping on the balancer while its running and squeaking and it doesn't change the sound at all. I've searched around the engine bay while holding a prybar up to my ear and pressing on things trying to listen for where the noise is coming from but still nothing.

At this point there's only 2 things I can think of. Thrust bearing/washer on the crank is squealing once the oil thins out. (but why now? 500km into driving it, wouldn't the tolerances be greater after break in, not smaller?) Or water pump once the thermostat opens, maybe there more/less of a load on it now that coolant is properly flowing?

TLDR
It can't be any of the belts, it can't be timing tensioner since that would make a sound all the time, not just hot vs cold. Its not oil pump, I highly doubt its rod or main bearing. And it doesn't seem like harmonic balancer.
I'm running out of things it could be. If anyone can take 45 seconds to watch the videos and give your 2 cents I'd be super thankful!

https://drive.google.com/file/d/1kB2...usp=share_link
https://drive.google.com/file/d/1k9x...usp=share_link

AngryBaconMan

Bump
Anyone have any vague ideas?

Maxcapacity

When you installed the timing belt, did you put the guide washers on correctly so the rib on the washers are facing the correct sides of the belt? Could remove the timing belt cover and check the sides of the belt for wear from rubbing? I have doubts that it might be the problem but just a thought.
Did you set the tension of the timing belt correctly? If the belt is too tight it could cause the issue.. Almost sounds like the water pump bearing but hard to say... Was the pump replaced when the rebuild was done?

AngryBaconMan

Yes I've checked the washers. The waterpump and tensioner are ok, I listened to each of them with a mechanics stethoscope. I've also entirely ruled out harmonic balancer, clutch throw-out bearing, and pilot bearing. I've also ruled out anything inside of the transmission.

At this point its looking like the crank thrust bearing/washer. I've gotta drop the oil pan to look at it. If its not that, there's nothing else I can think of.

K24_wagovan

I’m having this same exact issue currently. Noise sounds exactly the same as the video you posted. I’m completely lost been trying to figure this out for weeks. Did you end up finding out what the noise was???

AngryBaconMan

Yes I solved mine. I had an cheap oil catch can that was not venting properly. Excess pressure was building up in the crank case.

It had nowhere to go, so it was squeezing out past the rear main seal. Thus it sounded like it on was the crank shaft, a bearing, clutch, or anything part of the rotating assembly.

I almost yoinked the whole engine back out of the car to take apart everything, but I opened the oil cap and my noise instantly stopped. That's when I knew it was pressure in the engine.

K24_wagovan

hmm that’s interesting. I have a stock fully stock b18b1 that I just threw into a da integra. The noise does not happen until the engine is warmed up when it’s cold it will idle fine for about 10 mins then start making the same exact noise in your videos. We have to have the same problem it sounds exactly the same. But I don’t have a catch can and I’m pretty sure I have the pcv system all hooked up properly I’m not sure why I would have excessive crankcase pressure.

AngryBaconMan

Hmm, you might still have excessive blowby and it could be overwhelming your pcv setup. I'd pull the 2 vacuum lines off the top of your block, the one going into the air intake pre MAP sensor and the one going into the intake manifold post throttle body. Make sure you tape over the hole on your intake manifold where the hose was, or else you'll have a massive vacuum leak and your rpm will be all over the place.

kowalski383

Hey 'BaconMan' - Thanks for sharing your experience with this noise/situation. I just experienced the same (pretty much exact) noise as in your video, and needless to say I was getting concerned about my fresh engine rebuild (B20A5, 1989 Honda Prelude project). Just now went outside, cranked my car, let it run just a bit (it was still warm) and let the squeal start. Opened the oil filler cap a bit and the noise went away immediately. Tried it a few times for good measure, same each time (noise came back just a few seconds after tightening the cap)... I un-taped the end of the hose that normally attaches to the intake hose (right before the throttle body) (had it taped up since the breather hose/filter was still off), and that seems to have solved it for me. Really weird thing, but I'll remember it! Again, Thanks so much for sharing :-)