New unknown sound

Ok guys. Can't say I've heard this sound before. It is almost a whirring sound but not quite. Brief history. New torque converter put in, new starter and also new rear intake rocker. Here is the sound on YouTube.



Thanks for the help and the patience.

I adjusted the rocker again this time to 1/4 turn past zero lash and I think it made it a bit quieter but can still hear it. I can hear it in the cab at idle, but as soon as I touch the throttle the noise is drowned out.

When you replaced the rocker did you check the valve for clearances and free movement? Something made your other rocker fail, the noise may be related to that.

My other thought has to do with your bearings, and the amount of condensation you had in your crankcase. I bought a 390 many years ago that had been sitting outside in the car for two or three years and had a lot of condensation. It ran well, but I started noticing that the mechanical oil pressure gauge would fluctuate when I would accelerate and then back off. The bearings were loose. I pulled out the bearings and some of them were pitted from the condensation, causing the problem. The engine was a little noisy, too, more like a whining sound than whirring, and it quieted down after I put new bearings in.

Very good points. It isn't a solid whirring noise, it's weird. I checked the valve for movement and it seemed fine, there isn't any kind of binding or anything.

I had a coworker come over (a chev guy) who has rebuilt quite a few engines and he thinks it is just an exhaust leak. It did get quieter as I drove around, then when it sat for 3 hours it was noticeably louder until I got driving around again. So I really hope that is the case. I'll start tightening it all up tomorrow.

Kind of hard to tell from the clip but it does sound kind of like an exhaust leak around the manifold. I had the same issue. Pinpointed it with a stethoscope. Passenger side manifold had a small crack around the back two bolts. Swapped them out for headers. No more sound and better performance. A win win.

To me, it sounds like a dry bearing or bushing...some sort of dry metal on metal....something like the AC idler might make. I've heard drive belts making a similar sound as well. If you have a can of silicone spray, you could spray the drive surface of each belt while the engine is running and see if the sound goes away.

My first thought was an exhaust leak, too, but listening to it on my tablet didn't really sound like leaks I've had. Could just be the tiny (and tinny) speakers.

I agree with basstrix, sounds more like metal rubbing.

I'll listen on better speakers or my earphones.

My biggest worry was that it had something to do with the torque converter as it is coming from that side of the engine. But the sound does pulse.

Edit: If it is a bearing what would I look for. So far no sign of the oil getting burnt. But it may take more than 30 miles for it to start turning dark.

Edit 2: I guess when I send in for the blackstone report they will find any metal if it is a bearing.

moving the camera and showing the ground only made me sea sick . hold the camera stead pointed at one side of the engine then move to the other side.

Ok just for you I started on the drivers side then went to the passenger. Definitely louder on the passenger side. I drove the car another 20 miles today and I think the whirring is getting quieter. Oh I tightened down the exhaust bolts a little but sounded the same this morning.

Get a stethoscope from an auto parts store with the straw on the end and stick it down in different places. That sounds just like the clip I posted last year of mine and it was a cracked passenger side exhaust manifold.

Get a stethoscope from an auto parts store with the straw on the end and stick it down in different places. That sounds just like the clip I posted last year of mine and it was a cracked passenger side exhaust manifold.

Click to expand...

Ill go pick one up tomorrow, I do hope it is an exhaust leak. But Im becoming more and more convinced that it is the new rocker I replaced making the whirring noise.

Here is where I posted my video when it was the manifold.

http://www.7173mustangs.com/thread-horrible-sound-from-engine

Get a stethoscope from an auto parts store with the straw on the end and stick it down in different places. That sounds just like the clip I posted last year of mine and it was a cracked passenger side exhaust manifold.

Click to expand...

A section of vacuum hose also works quite well.

Hi, just wondering if you found the source of the noise yet?

I listened and it is definitely coming from the passenger valve cover. The noise is almost nonexistent now. So either the exhaust leak sealed up or the rocker needed to be broken in slightly. All I can say is that I have been enjoying driving it and if something breaks then at least I can say I got to drive it this summer.