my1968

Would love to enjoy a nice drive but the noise is driving me nuts...1968 newport 383 automatic... a couple minutes of warm up and then I get a noise that sounds exactly like a loose belt. So I pull all the belts and run the motor. Same thing...seems to be coming from front of engine near crank pulley...nobody seems to know what it is....could this be a timing chain issue? Anyone had this trouble before? Engine runs smooth and otherwise ok. Help!

blue 68 gts

How's your oil pressure?

Sounds like a bearing is about to go.

Gorts 5th

Maybe your sucking air through the carb manifold gasket...
i had the same issue sounded like a belt but the air being drawn through the worn gasket was making a squealing whistle...
i never heard of a squealing engine bearing... but there is a first time for everything. if a bearing is dry it would knock.

blue 68 gts

You're right. I know nothing.

bremereric

I would put a oil pressure guage on it and see if you have a drop in oil pressure. That would determine whether a main or rod bearing is squealing.

Gorts 5th

don't take that personal i'm giving some other options...
i have never had a "squealing" main bearing, if you or others have you have chimed in.
if his oil pressure was that low don't you think his lifters would be making a racket also not being able to get enough pressure to keep them primed? or do you think it's one bearing being starved for oil? pluged oil passage?

Mr.4spd

Do you suppose a spun cam bearing could squeal? I know a rod or main may knock, but there's no sudden loads on the cam...like explosions. Where the Hell is Roadrunner440 on this anyway?

70Coronet

My bet is on a air leak from under carb or intake - take a can of carb cleaner spray it around the base of carb and intake-noise will stop for a moment and car will either rev or die, --just had this exact same scenario at our shop from a older chevy pickup-thought it was alternator bearing once we ruled out belts then realized it was just a high pitch whine/whistle noise exactly like a belt coming from a air leak at the base of the carb.

Gorts 5th

That's what i'm talking about...

440roadrunner

With the belts removed and the engine nearly cold, start the engine and get it to some RPM which causes the squeal. Undoubtedly easier with an assistant.

Get a scrap of hose, fuel hose, etc, and hold one end to your ear, and probe around in the area from where you believe the squeal is coming. You should very quickly be able to find it. This method works well for exhaust leaks and some vacuum leaks.

mikerp76

could be the dizzy.

moparted

bearings

TVLynn

Lack of oil to the rocker arms. Spun cam bearing could cause it I is blocking the oil passage to the rockers

dartcuda

I seen this problem but only after a rebuild or a new timing chain.The oil slinger was put in backward and was rubbing on the timing chain cover.

Gorts 5th

iv'e have heard this when a crank pulley bolt was to long and was rubbing an the timing chain cover.

pro-tech

I agree with dartcuda, or it could be the crank seal . Do the hose trick it will help you isolate the noise. Also if there was low oil pressure the first thing to make noise would be the lifters it would sound like a singer sewing machine on steroids. Keep us posted

mattyg50

did you ever get the fix? mine is doing the same thing!! (383) only when it in the middle of the temp guage, all belts off, sounds like a super loose belt!! i rebuilt the motor a few years ago, probaly have a bout 3,000 miles since. i wonder if my oil slinger is on backwards? any marks to tell which way it goes?
thanks!

TVLynn

Lube the dist cam. if you still have points

mattyg50

I found my oil slinger rubbing at the top area of the timing chain cover, and yes it was on correctly. my noise would only happen when it was at the middle temp. I heard the double roller timing chains being thicker can make the oil slinger rub?? its just my guess, but im going to install it without the slinger

Moss

Rod or main bearings don't squeal.