# Harmonic balancer is wobbly.



## Shut-Trip (Oct 18, 2012)

*
Make: Nissan
Model: Pickup
Year:1997
Engine: 2.4 L 4 cyl.
Body: XE
*

I was noticing some issues similar to a previous post from:


noise - weed eater in there?
post from: ajriding
back on october 2015

At this point, I ve noticed that the 
main pully , and the Harmonic balancer 
is wobbly. ( I have over 200K miles on this truck.)
so Im trying to source out a Harmonic balancer .
I learned about the important function of this little understood 

device/componet. and think this will help, if i have it replaced with a 

new one.

Ive found one at the local dealer for about $250.00 - 
and next to to check with the local junk yards.

has any one replaced the Harmonic balancer ?
and were they able to find a decent (aftermarket, or OEM) 

replacement balancer ?


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## Shut-Trip (Oct 18, 2012)

*Found Tip / solution*

I think I Found Tip / solution, for my own question:

from a post from last year:
from another member:
" If you want a Nissan part, it's 12303-86G0A and MSRP is $226.62, but you can get it from 1stAAANissanParts.com for $163.16 + shipping. "

Shut-Trip.:nerd:


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## smj999smj (Jan 1, 2006)

1stAAANissanParts.com is now defunct. Try CourtesyParts | Genuine OEM Nissan Parts & Accessories


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## Shut-Trip (Oct 18, 2012)

ON THAT WEBSITE, I FOUND A PART:
PULLEY - 1997 NISSAN PICKUP (123038B000).
BUT IT SAID IT WAS DISCONTINUED.

THE PART NUMBER THAT THE DEALER PROVIDED WAS: 12302-86G0A FOR 264 DOLLARS.

I PLUGGED THAT PART NUMBER IN THE WEBSITE,
AND IT CAME UP, BUT IT LISTED AS FOR '95 PICKUPS. LITTLE CONFUSED....

IF I GO TO THE DEALER'S HOUSE WITH THE BRICKS AND MORTER, I KNOW I'LL GET THE RIGHT PART. BUT I'LL PAY A LITTLE MORE, MAYBE A LOT MORE...HUMMMM...

MEAN, IS IT WORTH $80 TO RISK GETTING A
PART THAT MIGHT FIT THE BILL ?


ON THE BRIGHT SIDE, Beyonce Returning to Super Bowl Halftime Show.


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## jp2code (Jun 2, 2011)

On another forum, a guy was having a hard time recently getting his harmonic balancer on. It looked like he'd been trying to pound it on with a 5-lb sledge hammer. The hole for the shaft was all flared out.

I'm not saying it was you, but if someone before didn't know what they were doing, they could have jammed the harmonic balancer on there wrong.

In my experience, Courtesy Parts winds up being the same price as my local dealership. If I let their guy look up the parts, pay for it there, and they get me the wrong parts, I can just hand it back and say, "I need the correct one."


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## smj999smj (Jan 1, 2006)

Crank pulley 12303-8B000 was replaced by part number 12303-86G0A.


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## Shut-Trip (Oct 18, 2012)

This is an update after the repair: Had the Trucks Engine's main pully (witch has the Harmonic balancer built in appearently) replaced. I bought the parts, after I sourced out a Harmonic balancer at a reliable local Nissan Dealer / Parts Department. it was about $250.00, and I decided to have a actual garage do the job, another $250. 00.
Heres the benefit:
First and formost, the wobble on the front of the engine is gone, and I am able to drive long distance again.
second, I learned or re-learned the important function of this little understood device/component: In a Internal combustion engine, at certain RPM's there may be harmonics, vibration .


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## OhmsLaw (Mar 29, 2016)

An LC circuit will oscillate and a resistance in this circuit damps out the oscillation. It lowers the "Q" of the circuit.

As it was explained to me, the analog of a resistor in a mechanical rotational system is a mass attached with a viscous material to a shaft. 

If a high Q crankshaft oscillates, more and more of the engine power will go into feeding these oscillations and destroying the engine, rather than moving the car.

The oscillation amplitude does not build up, instead it goes into heating the resistor, or heating the compliant material that fastens the balancer mass to the shaft end.

Low Q things don't oscillate, like a crankshaft (or a bell) made of lead.

Supposedly there are analogs between electrical, mechanical, hydraulic, etc., systems. Like I could see RPM being an analog of voltage and torque being an analog of current.


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## Shut-Trip (Oct 18, 2012)

Yeah, what I do to test for vibration, some one told me if you "put a coin, like a nickel, on top of the valve cover, and while the engine is running, while still in park. If the coin flips from heads to tails, then you have a vibration problem..
-shunt trip.


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## OhmsLaw (Mar 29, 2016)

Never heard that one.

I'd look for lateral movement at idle at the crankshaft pulley and then compare it to what you see with one plug grounded. 
But the RPM may change and this also depends on how many cylinders you have and the condition of the motor and xmission isolators/mounts.

Plus or minus 1/16" has four times the vibration energy of +/- 1/32". A stroboscope might come in handy, but they cost.


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## smj999smj (Jan 1, 2006)

Engines will either have a "crank pulley" or "harmonic balancer" at the front of the crank. Engines that are internally balanced, like Nissan's VQ engines, will have a "crank pulley." If the engine is externally balanced, then it will have a "harmonic balancer."


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