Engine: like a strange bird noise

[Flat4ever]

First : it is not a joke...

Second : the facts

My '73 double carburated 2.0 runs well, but ... when the engine is middle hot, a strange "cui cui" noise comes.

Example: I leave home, I drive about 20 kms, no noise. I stop the engine and 15 minutes later, if I start the engine again I hear a strange "cui cui" noise comes.

It is directely indexed on RPMs. It does not seem to be the clutch. The noise is here when pedal pressed or not. If I rev up the engine, the noise decrease but when I use engine braking, the noise comes back. The noise comes from the impeller aera. Alternator ? Distributor ? Bearings ?

I know that you won't fix the problem without hearing the noise, but may be this happened to somebody ...

[Bruce Allert]

I remembered a post awhile back with the same indications. Check it out & maybe you'll have some luck.
Chirrrrrrp
bruce

[norustscott]

Lube the distributor cam...where the points make contact...just a "petite" amount of grease will work but dielectric??? grease in purpose made.
Check fan/alternator belt tension
Check sheet metal screws. vibration at idle can cause metal on metal chirp noise.

[tryan]

check the belt alignment and for objects in the fan.

[Kevin Powers]

also belt tension.

[Zeke]

Hungry newborns in fan housing.