"Howling" noise

I am very interested in this thread, Im looking forward to you finding out whats causing the sound, I myself hate when I hear noises , whether in my truck, car, or bikes, and cant find where they are coming from.

Thank you

 

crank pulley noise at startup is very common on many cars from that era, will not be surprised if it's that or even the small bearing inside that pulley housing.

 

Here is a video of my car on cold start (1st start of the year today). Been making this sound, on and off, since the day I got it, June1, 1985.

 

Have you checked the AAV?
Auxiliary air valve, should be easy to locate as the hose from under the air filter box runs right to it.

 

That is a weird noise, sounds like its an air leak somewhere.

Thank you

 

(hopefully won’t eat my words later) Both my 84 GTB QV and 85 Euro QV never made a sound like that at start up..

 

That is a typical water pump bearing noise.

 

Did you read post 29?

Why would a brand new 308 QV do that?

And why after 36 years would the original water pump on that car still be functioning perfectly. I can't imagine a bearing howling like that for 36 years would be damaged leading to failure.

And why in 36 years wouldn't a single tech that worked on the car mention it as a potential problem?

 

The only things that are directly connected to the crank that could make that noise is:
Lower drive gears, bearings
Oil pump

The drive gears would be noisy as well, you don't report that to be the case.

That leaves the oil pump. It's gear driven right off the crank and sits right behind the crank pulley. The gear pump is straight cut gears with loads of axial movement, there really is a fair amount of play between the gear lash and the housing. My guess if you're not experiencing any issues is that gear pump is vibrating, chattering about in those tolerances until it heats up and those clearances close up a bit.
It really sounds more like a whistle, high pressure flow thru a reed valve. Still could be the pressure valve, cold oil, higher viscosity, greater pressure differential creating pump harmonics. But could easily be why the factory updated the spring. Shorter spring and shim increased the spring rate to reduce/remove that problem.

 

If no one can point a finger at the true cause after, well at least 36 years, I don't see an epiphany coming here anytime soon.

 

I don’t think there’s a problem but quite interesting where that sound is coming from. I would think if it’s a bearing, oil pump or water pump etc. the sound would be consistent until it reached certain operating temp or volume? Definitely sounds like a whistle to me.

 

Remove all the accessory belts..maybe leave the a/c compressor belt as its a real pain to remove. So alternator and water pump belts. Start the car. Has anybody done this in the past?

 

Not so sure about that. I just did a belt service on a 328 last week and the a/c belt was the last to come off and the first to go on. The order is alternator, water pump, a/c. Unless there is somthing wired about your car they are all set up this way.

 

Ok, last thought...
I've seen this on at least 3 engine builds. Abnormal bearing wear on just the #1 crank journal. Cause? The A/C belt was to tight and the wear was in the pull direction of the compressor. At cold start there's little to no oil in the journal. Can it cause that noise? Maybe....

It's funny I've tracked down all kinds of crazy noises on these engines. They buzz fairly high and stuff comes loose. Had one that would make this harmonic rattle/buzz at 3.5-4k rpm... Very irritating. Turned out to be the dang coolant pipe that drops down past the fuel tank... The one that sneaks past the alternator. It was vibrating off the tank strap... Foam insulation on the strap fixed it.
There's also the other issue I've seen a lot, alternator cuts into the coolant pipe.

 

Very infrequently my '87 will make that same noise usually in cooler weather. For years and years......

 

Maybe try and use belt conditioner ? Maybe the humidity softens the belts and or keeps them quiet ? , and dryer weather causes them to generate the howl ?

Thank you