Can the harmonic balance come loose?

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myasylum

myasylum

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This engine has about 10, 000mi on a rebuild.
I was driving it today and I was hearing a noise That sounded like something was loose. I only would hear it when I would stop. When i would speed up the sound would go away.
I didn't check real hard yet because I'm not feeling real well today but when I looked it appeared that the harmonic balancer may be loose and that is what is making the noise. Do you think this could less to other troubles like the crank shaft, or bearings?
Thanks.

Oh this is on a 360.
 
The balancer is made of 2 parts bonded together with rubber. Its more common for them to come apart than come off.
 
YES. It can certainly come loose.
 
It could very well be the crank pulley loose on the harmonic. It happened to me in my parents' Caprice wagon with a 454 when I was a teenager. Heard a rattle now and then, and you know I was always taking that sucker to redline every other minute.

Then one day I sent that crank pulley right up into the fan and radiator. Watch out.....check it out before you keep driving it.
 
:D I was going to mention that.
Seen it before, and can make a heck of a rattle.


cudavert said:
It could very well be the crank pulley loose on the harmonic. It happened to me in my parents' Caprice wagon with a 454 when I was a kid. Heard a rattle now and then, and you know I was always taking that sucker to redline every other minute.

Then one day I sent that crank pulley right up into the fan and radiator. Watch out.....check it out before you keep driving it.
Click to expand...
 
I,m sorry, that was a short reply. It won't make noise, just screw the timing up. Exactly ,what does the noise sound like? Where is it coming from?
 
Could be the crank pulley, check it to see if it wobbles If not check your flex plate. Mine broke at one of the tabs and would only rattle at idle.
 
The outer ring can move. I had one wipe an entire engine out after 450 miles.
 
I have had a harmonic balancer come off. It doesn't make a sound until it comes off then there is a hell of a racket as it destroys other parts. If you are hearing a rattling noise at idle I would check the flex-plate then the heat riser.

Jack
 
Sorry, to bate you guys and leave but I ended up with the flu.

Here is a cool .gif that my friend made so you can see whats going on.

not cool...

Anyone want to buy a Duster?
cWFkE1J.gif
 
Oh wow, that's the coolest right there!! Well, that reminds me of an engine I got in a package deal with a car. The engine was in pieces and I believe was mated to a 4-speed gearbox at one time. At any rate, there wasn't enough clutch pedal freeplay (my theory) and you should've seen how the crankshaft got shoved forward, right into the main thrust bearing! It looked like about a 1/4" got "hogged out" of the crank AND main saddle!

You're not running a stick shift, are you?
 
No, Automatic.
I drove it about two miles like this. I had to get it at least home.
It only made noise at idle, drove fine all the power was there. Still after I saw this, it hasn't been started since.

Any ideas of where to go from here? Thrust bearing, hey?
 
Good to see you have the problem identified. That could get serious and leave you sranded. Happened to me while cruising in my buds 67 malibu. Except the balancer came right off! Damaged the keyway pretty bad,left us stranded!
 
If your buddy was really talented he would have figured out how to make it move like that while it was also rotating.....along with the fan & waterpump....
 
cudavert said:
It could very well be the crank pulley loose on the harmonic. It happened to me in my parents' Caprice wagon with a 454 when I was a teenager. Heard a rattle now and then, and you know I was always taking that sucker to redline every other minute.

Then one day I sent that crank pulley right up into the fan and radiator. Watch out.....check it out before you keep driving it.
Click to expand...

I built a 454 for a 71 Monte and had the water pump shaft shear off while i was under the hood revving it!!! Only 8 lives left now.....

Ported 396 heads , 10:1 KBs , 550ish roller Comp , RPM intake msd 6al / distributer and headers. My 340 would have eaten it ! My first and last venture into chebbies! Could have been lack of experience with them..but still
 
Can the thrust bearings be replaced from the oil pan? Is it necessary for a complete tear down?
 
The crank will have to come out to replace the thrust bearing.

I might have come off a bit harsh in my post above, but I'd say 95% something is screwed up with the thrust bearing. Try tightening the balancer bolt if you like, it'll only take 5mins but don't go crazy. If it doesn't budge then you've got bigger issues and you certainly don't want to go swinging off that thing and possibly snapp the balancer bolt (that'll require some force though).

Why this has happened on an engine with only 10K on it, I can't say.

edit: funny enough a friend's 318 used to do the same thing. In neutral he'd give it a rev and we'd watch the crank move back and forth at least 1/8th of an inch
 
blownhemi said:
That's not going to fix it, the thrust bearing is hammered. Time for a tear down.
Click to expand...

blownhemi said:
I might have come off a bit harsh in my post above, but I'd say 95% something is screwed up with the thrust bearing. Try tightening the balancer bolt if you like, it'll only take 5mins but don't go crazy. If it doesn't budge then you've got bigger issues and you certainly don't want to go swinging off that thing and possibly snapp the balancer bolt (that'll require some force though).
Click to expand...

exactly


Both sides of the thrust bearing would have to be gone, to get that amt. of movement.. and not likely to have broken crank.. - so loose bolt, hopefully, and only "takes a coupla mins to check"..

The 2 experiences I had with burnt out thrust bearings,, the motors stunk, the 2 friction surfaces turned blue from heat, the smell of burnt oil was unmistakable,, especially when running..
 
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