Danny456

While out driving around town i heard an unusual squeal metallic type sound fromm the engine. I quickly drove home and parked in the garage. When it was in nuetral and i took the RPMs up to exactly 1500 the sound came back. it seems like the sound is being produced from the front of the engine. What could it be? I checked all the belts they were tight. Now i need to know where to look next. 73 350 4 speed. edelbrock heads, manifold, cam and carb. Any sugestions are aprreciated.

Danny

TortureTest

Alternator ? I would look at things that move at a certain rpm, alternator being one of them....is it a vibraty sound ? You should be able to ascertain that it is or is not inside the engine......just your couple of comments lead me to believe that you suspect it to be outside the engine.

Danny456

yes it sounds kind of shaky and like metal clanking sort of. Sorry for the poor explantion it is just a very weird sound.

dannyman

Could be worn bearings from either alternator or water pump. Use stethoscope to listen to bearings or I have also used a long screwdriver as a stethoscope. Pay attention to drive belts, run engine and you should be be able to isolate by sound.

Cory1970

I vote water pump.

Danny456

well i went out and took all the belts off and ran the engine for about 15 - 20 seconds. The sound was still there so that elminates power steering pump, water pump, or alternator. This must mean that it is something internal?

Artsvette73

Exhaust manifold leak?

LeMans Pete

Doesn't sound like a whine? Like a throwout bearing? Are you positive its coming from the belt area or could it be coming from the tranny? Sometimes sounds get thrown around a bit.

King Lear

also it could be the crankshaft, I had the same problem and had to put a shim behind it to even it up, my builder just put some washers behind it and it was rubbing on the timing pointer.

dannyman

Harmonic Balancer?
Windage tray?
Main bearing?
Check harmonic balancer for signs of rubbing. I would get someone to start/stop engine while I continued to troubleshoot.
You should fill in your profile so we know what you have. ie: A/C, stock or electric cooling fan, air pump with original exhaust or headers???

Frustrating to have a noise like this and not find the source! Noise at high RPM leads me to believe that you have something loose and it vibrates at certain resonance. ie: windage tray

Would also check motor mounts.

Blue79

I once worked on a Chevy engine that had a timing chain so stretched that it wore a hole in the tin timing chain cover. Try putting your stethoscope there to check for unusual noise.

HobbyPoor

I know this is an old thread...but im having same exact issue...

you ever find a solution/cause

73StreetRace

As nobody said it yet, could it be a camshaft sprocket bolt scratching the timing chain cover ?

gingerbreadman1977

timing marker hitting balancer maybe

mar

You can also use a very long screwdriver shaft and carefully place the tip end against components and put your ear on the handle and listen. works great. Just be careful.

James

Go get a automotive stethascope. About $10.00 at autozone. Put it on and and work around the motor. You will be amazed at what you can here. You can hear the valve train perfect, bearings turning, timing chain noise. I used them to find a noise I had and traced it down to the carb whistling while at idle.

HobbyPoor

Im gonna check tonight...From what Ive found is that its possibly vaccum being sucked in past one of the crank seals. Im gonna check that tonight.

we will see how it goes....