Howdy
It's been a minute, but this summer I rebuilt my first D-series engine for a '99 civic my friend gave me.
It's back in the car now, and running great! But after reaching temperature for the first time I heard this noise begin, and now it's pretty constant at idle.
Video of it, but the sound is pretty quiet:
https://video.berocs.com/w/sgeE4cPX3AuuQCouG1FNvd
Doesn't go away with clutch, so not a pilot bearing or anything. Also isn't affected by mucking with the air filter and butterfly valve, so likely not whistling at the throttle body. I removed all of the accessory belts (power steering, AC, alternator) and the sound is still there.
Eventually I read that having the timing belt too tight can cause a whine. Bingo, I even recall ignoring the service manual and pressing a little on the idler pulley to tighten the timing belt more when installing it. I must have overtightened. So I went out and ripped the darn engine bay back apart to get a ratchet down next to the idler and loosen it. This time I followed directions: Set TDC, loosened 180 degrees, rotated crank to pull cam 3 teeth past TDC, and tightened to about 30 ft lbs.
Buttoned the engine back up, but the whine is still there. My current thought is that the sound is either damaged water pump pulley or damaged cam journals, but I have no idea.

It's been a minute, but this summer I rebuilt my first D-series engine for a '99 civic my friend gave me.


It's back in the car now, and running great! But after reaching temperature for the first time I heard this noise begin, and now it's pretty constant at idle.
Video of it, but the sound is pretty quiet:
https://video.berocs.com/w/sgeE4cPX3AuuQCouG1FNvd
Doesn't go away with clutch, so not a pilot bearing or anything. Also isn't affected by mucking with the air filter and butterfly valve, so likely not whistling at the throttle body. I removed all of the accessory belts (power steering, AC, alternator) and the sound is still there.
Eventually I read that having the timing belt too tight can cause a whine. Bingo, I even recall ignoring the service manual and pressing a little on the idler pulley to tighten the timing belt more when installing it. I must have overtightened. So I went out and ripped the darn engine bay back apart to get a ratchet down next to the idler and loosen it. This time I followed directions: Set TDC, loosened 180 degrees, rotated crank to pull cam 3 teeth past TDC, and tightened to about 30 ft lbs.
Buttoned the engine back up, but the whine is still there. My current thought is that the sound is either damaged water pump pulley or damaged cam journals, but I have no idea.