Diagnose Engine metal scraping noise?

[Prospect Farms]

My "better" tractor, the 3 cylinder: 154 CID gas (ford 2000) makes a loud, metal-on-metal screech when I turn it over. Nothing external, like fan shroud, water pump or generator is causing it.

Frequency of noise increases with the rpm of engine, like a nock on just one cylinder might. Doesn't sound when I turn it over by hand. Thought maybe it was a bent push-rod, but after pulling rocker assembly saw there was plenty of clearance, and rods are straight. Valves also seem to move freely.

Tractor would start if I tried, but I wont let it run with that noise.

Intermittent nature of noise makes me think I spun a rod rather than a crank or cam bearing but I've never heard that kind of fingernails-on-chalkboard sound coming from an IC engine, so I'm only guessing.

Found some H20 in the engine sump a month ago and serviced the oil and filter. A week later, when it was 25 degrees F., I tried to start the tractor and first heard the noise.

Does this sound (no pun intended) familiar to anyone?

Thanks,

 

[Fordfarmer]

I've heard generators make a noise like that. Try loosening the fan belt, so the genny doesn't turn, and try starting it.

 

[sotxbill]

Water pump or generator... Usually a generator bearing is going bad. And the little fan on the front of the generator is sqeaking. Take off fan belt and try it.. But dont run it but for a few seconds..

let us know. Bill

 

[old]

First off how do you know it is not from the water pump or generator etc. Did you remove the fan belt to check??
If you answer yes to the first thing then sounds like it is time to drain the oil and look for metal floating in the oil, looks sort of like a little silver sheen in the oil. If you see that then you have a major problem is not you could still have something like a broken ring or a waist pin problem and pulling the head and pan may show you where the problem is

 

[mowr]

"Doesn"t sound when I turn it over by hand."

Starter?

 

[Prospect Farms]

Thanks to everyone who replied. Noise is very loud and only comes on when engine is firing. Sounds internal, but there's no way to know until I go through some more diagnostic work. Time to pull the top and bottom off the engine and have a look. Thanks again.

 

[Cthomas]

My "better" tractor, the 3 cylinder: 154 CID gas (ford 2000) makes a loud, metal-on-metal screech when I turn it over. Nothing external, like fan shroud, water pump or generator is causing it.

Frequency of noise increases with the rpm of engine, like a nock on just one cylinder might. Doesn't sound when I turn it over by hand. Thought maybe it was a bent push-rod, but after pulling rocker assembly saw there was plenty of clearance, and rods are straight. Valves also seem to move freely.

Tractor would start if I tried, but I wont let it run with that noise.

Intermittent nature of noise makes me think I spun a rod rather than a crank or cam bearing but I've never heard that kind of fingernails-on-chalkboard sound coming from an IC engine, so I'm only guessing.

Found some H20 in the engine sump a month ago and serviced the oil and filter. A week later, when it was 25 degrees F., I tried to start the tractor and first heard the noise.

Does this sound (no pun intended) familiar to anyone?

Thanks,

 

[Cthomas]

I have a similar tractor with what sounds like the exact same issue. What was your findings if you don't mind sharing. Thanks