My slant 6 V-200 225 has started to make a very loud high pitch chirp after full warm up. Once the chirp starts I listen to it at idle and it seems to tone down for a milli-second or go away then back again just as loud in a matter of the same time. It's chirping intervals match the motors rpm, more throttle gets faster chirp. This is like a soft metal chirp, not a grind as heavy metal would have.

This is not a knocking, clicking, pinging, grinding, or ticking sound. It is a definitive chirp like a little bird but loud as hell.

I have checked the belt, the pulleys spin free, removed the valve cover to be sure it wasn't in the head as I rebuilt it recently using heavy duty springs, lifters, valves, ect. I have no blue/blackish smoke at all so I don't think it's rings either.

At this point I am thinking bearing or possibly a wrist pin??

Can anyone possibly diagnose or lend advice? I don't have anything to listen with and the old "long thin hose" trick won't work as the motor is loud and drowns out the sound. Thanks in advance.

Exhaust leak??

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Mattelderca
78 NYB (gone now), two S series, three old Snow Cruisers and a Doo.

Check to see if all the rockers have oil coming out of them.

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Official Cookie and Mater Tormentor.

Bad PCV valve?

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1964 Dart GT

Pull-off the fan belt and run the engine for a moment...
It could be the accessories or the belt.
DD

Glazed belt is my guess. I second what Doc said.

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Casually looking for a Clifford hyperpak intake for cheap.

Thanks for the fast responses everyone.

It's definitely not exhaust leak good thought though.

Going to go with what Doc and Reed suggested first as that's the easiest start. Next I'll check PCV but I doubt that is it.

Slantzilla seems to have a decent thought as well so if the former doesn't yield any results I'll go with this. When I had the valve cover off previously I didn't check that. Just a quick listen and visual.

Could be water pump bearing or alternator bearing, as Doc said pull belt for a short time.

Richard

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Part of Tyrde-Browne Racing