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Discussion Starter · #1 ·
Ok...here goes.

I've got a '83 258 that has been making an odd hollow noise lately. I can't quit get rid of it.

The hollow noise sounds like a muffled cowbell coming from the from of the engine, in front of the radiator. At idle, after a hard hour of driving, it gets more persistent and louder.

-I could always hear it at higher RPMS.
-It would go away at mid-range RPMs
-I Replaced the harmonic balancer w/a new one, and a used but nice crank pully yesterday.
- The noise it much quieter now, non-existent at higher RPMs.
-At idle however, the noise is still there, very vaguely, but there.
-With both belts and the waterpump pully removed, noise is still there at idle(550-650RPM).

Maybe a NEW rather than used crank pully?
Any other guesses?

Thanks for reading...I really appreciate the knowledge I gain from this board.
 
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Warm the engine up....
And then take off the belt.
Start the engine and let it run just long enough...30sec max...to see if the sound is still there....

If so, it's in the engine....and unless it has been rebuilt recently, don't worry about it...it's getting old and tired...drive it until it doesn't go any more.

If the sound went away then start checking everything that the belt drives.

BTW...did you try a bar of soap on the belt?
 

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Check for play in the timing chain. LEVE will come along soon, I think he's got it written up. Otherwise, it’s just a matter of marking the rotor in the distributor and see how many degrees you can move the crank backward before the rotor moves.
 

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Check the balancer. If the media's torn/cracking/checking then that can induce a wobble/off blance to the balancer. Usually it makes a real dull thud sound till it tears away and then it's a pronounced metallic sound.

Can you ID to see if the sound is timed with engine rotation?
 

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I have always found that a hollow clanging bell-like noise like that is the fan hitting the shroud.
 

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Discussion Starter · #6 ·
I just replaced the balancer two days ago...the old one had some cracking/warping in the rubber. The only thing consistent about the sound is the tone...the rhythm is relatively sporadic. It occurs at low RPMs/Idle(550-650), I don't what else to make of it.

I've got the timing set to 6*BTDC...the sound doesn't go away with different timing settings. If you put your face in front of the radiator you hear it best. My only thought is the crank pully,(which is used, but very straight/true),is not lined up/balanced properly.

How can I verify that it is not the timing chain?
What about a crankshaft bearings? The old balancer had a good wobble to it. Could the replacement balancer be too little,too late?
 

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[ QUOTE ]
If you put your face in front of the radiator you hear it best. My only thought is the crank pully,(which is used, but very straight/true),is not lined up/balanced properly.

[/ QUOTE ]

this is from way out in left feild, but if the noise has no real rythym to it(ive always believed that an internal engine noise will have rythym to it), could it just be the radiator itself expanding and contracting as it works? just a thought, but the description does sound like the noises steam piping makes when ya start the system......

[ QUOTE ]
The old balancer had a good wobble to it. Could the replacement balancer be too little,too late?

[/ QUOTE ]

could be, what exactly was wobbly, was it the main crankshaft bearing at that end? the old balancer bore/keyway out of round? the end of your crankshaft worn out of shape?
 
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