harmonic balancer 91 vette
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Burning Brakes
Joined: Jun 2003
Posts: 949
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From: smithtown ny
harmonic balancer 91 vette
has anyone heard of the harmonic balancer ever going bad in corvettes?? and if so will it throw of the timing at just wot or through out the rpm range?????? what are the signs of a bad balancer????
Instructor
Joined: Oct 2003
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From: Holbrook NY
Re: harmonic balancer 91 vette (6spd)
For a balancer to fail or slip in some way that will give a bad timing reference is virtually impossible. The only possible way that I can imagine this happening at all, would be moments before a catastrophic failure, just after the outer portion of the balancer has completely separated from the rest of the assembly.
Timing trouble does occur from mis-reading the timing degree marker, or having the incorrect timing plate. Sometimes I find a nice chrome marker plate installed, that looks nice, but is marked wrong!
-George
Timing trouble does occur from mis-reading the timing degree marker, or having the incorrect timing plate. Sometimes I find a nice chrome marker plate installed, that looks nice, but is marked wrong!
-George
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Joined: Oct 2003
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From: Holbrook NY
Re: harmonic balancer 91 vette (George West)
Signs of a bad balancer might be:
wear marks or damage to the serpentine belt
any sign of contact to the front engine cover
any play, in any direction, indicates a problem - possibly damper related.
excessive engine vibration while car is stationary
wear marks or damage to the serpentine belt
any sign of contact to the front engine cover
any play, in any direction, indicates a problem - possibly damper related.
excessive engine vibration while car is stationary
Instructor
Joined: Oct 2003
Posts: 147
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From: Holbrook NY
Re: harmonic balancer 91 vette (atotalnincompoop)
Wow - I do not know what causes that particular type of failure. When I installed my new FluidDamper, it was very solidly keyed into place, and the big-butt nut on the end of the crank is quite tight.
If the harmonic balancer can slip, I would expect that it would not slip into a fixed position, but rather move around more an more over time. The rotational forces on the balancer are reversed, depending on whether the engine is accelerating or decelerating. Revving the engine up fast might give you a different base timing value than if you gently ran down to an idle.
In the case of timing changing due to a slipped balancer - keep in mind that the actual ignition timing is not changed. It only looks wrong. Find true TDC, and make your own static adjustment - and leave it alone. The balancer moving makes it impossible to use as a reference.
Don't change the balancer because the timing reference is wring.
Change your balancer because the engine is misaligned to the balancer, vibrating mile after mile off the engine's life expectancy;
and because harmonic balancer self destruction looms ever larger on the horizon.
-George
If the harmonic balancer can slip, I would expect that it would not slip into a fixed position, but rather move around more an more over time. The rotational forces on the balancer are reversed, depending on whether the engine is accelerating or decelerating. Revving the engine up fast might give you a different base timing value than if you gently ran down to an idle.
In the case of timing changing due to a slipped balancer - keep in mind that the actual ignition timing is not changed. It only looks wrong. Find true TDC, and make your own static adjustment - and leave it alone. The balancer moving makes it impossible to use as a reference.
Don't change the balancer because the timing reference is wring.
Change your balancer because the engine is misaligned to the balancer, vibrating mile after mile off the engine's life expectancy;
and because harmonic balancer self destruction looms ever larger on the horizon.
-George
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Joined: May 2002
Posts: 541
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From: Kalama WA
Re: harmonic balancer 91 vette (6spd)
Mine just went bad 3-4 months ago on my 86. Balancer spun outer ring 2-3 inches and towards rear of car .25 inches. Only reason I found it was the timing mark was way off and packing was peeling out on balancer. YES, it can happen.
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Instructor
Joined: Oct 2003
Posts: 147
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From: Holbrook NY
Re: harmonic balancer 91 vette (GlockLT4)
If you have this unusual problem happen to you, it is a great time to install a FluidDamper. The stock dampers are static balanced - kinda of. They are of the "one shoe fits all" variety. They do not dampen vibration as well as a dynamic (fluid or jel) type.
So do not install the stock damper, if you are installing a damper.
George
So do not install the stock damper, if you are installing a damper.
George
