Unusual sound from engine
Thread Starter
Intermediate
Joined: Jul 2006
Posts: 43
Likes: 0
From: Claremont Ca
Unusual sound from engine
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
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
Pro
Joined: Jun 2005
Posts: 561
Likes: 0
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.
Melting Slicks
Joined: Dec 2006
Posts: 2,669
Likes: 3
From: Kingston Ontario
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. 
Thread Starter
Intermediate
Joined: Jul 2006
Posts: 43
Likes: 0
From: Claremont Ca
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?
Melting Slicks
Joined: May 2006
Posts: 3,438
Likes: 41
From: Raleigh NC
St. Jude Donor '13-'14
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.
Last edited by LeMans Pete; Jun 15, 2007 at 10:42 PM.
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Melting Slicks
Joined: Dec 2006
Posts: 2,669
Likes: 3
From: Kingston Ontario
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.
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.
Instructor
Joined: Jun 2006
Posts: 146
Likes: 5
From: North Brunswick New Jersey
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.
Burning Brakes
Joined: Dec 2007
Posts: 889
Likes: 0
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.
Burning Brakes
Joined: Nov 2000
Posts: 948
Likes: 0
From: Johnston Iowa
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.