For those experiencing phantom engine vibrations..

Our LS400 Harmonic Balancers are 20 - 30 years old.

The Crankshaft harmonic balancer is a device connected to the front of an engine’s crankshaft, incorporated within the crankshaft pulley.
Its purpose is to absorb and reduce harmonic vibrations from the engine as the crankshaft rotates, as harmonic vibrations can cause accelerated wear and damage to engine components.
LS400 balancer is made of rubber and metal, that dampens harmful.harmonic vibrations.

Oftentimes one of the first symptoms of a potential problem with the harmonic balancer is engine vibration.

The harmonic balancer is specifically designed to facilitate a smoother idle and absorb harmonic engine vibrations as engine speeds rise.
If the harmonic balancer is old (ours are 20 - 30.years way too old) or fails and can no longer properly absorb the harmonic vibrations, the engine will shake excessively. (Arguably any engine vibration in a 1UZ-FE is excessive.)

While the 1UZ-FE is a very smooth engine, nuanced vibration or shaking will become even more pronounced if harmonic balancer issues.

Numerous ClubLexus member posted RPM specific engine vibrations and/or catastrophic failure of rubber ring causing separation of the hub and outer shell of the harmonic balancer...

Unsafe at any speed....

Highly stressed rubber, such as that sandwiched into OEM harmonic balancers are failure prone after 20 years.


Representative Harmonic Balancer fairly depicts typical inner hub, outer shell and rubber damping ring typically used in LS400

Based on age alone, all LS400 Harmonic Dampers should be replaced.

As with timing belts, Harmonic dampers require periodic replacement.
After all, irrespective of mileage, anyone informed would not consider running an engine on 20 or 30 year old timing belt, but do so with a 20-30.year old harmonic balancer.

Input welcome.

 

From my experience, your typical part store balancers are just as bad as the 30 year old originals. I've had many advance balancers start to shred anywhere from 3 to 5 drift events in. I've had multiple older Hondas come through that after they were replaced, the woodruff key would start eating into the key way. Most of the key ways are too snug to fit the original woodruff key. They need to be a perfect match or you end up with 1.6 Miata issues.. This is one of those things that you really should spend the extra money on to get oe or a name brand aftermarket performance part like ATI.

If you do get one from a part store, make sure the key way is perfect (slip the woodruff key in), the stub is square, and you can't move the metal. Also, replace the woodruff key..

 

The balancer on my 94 went bad around 185k. The inner rubber part was coming apart and it was wobbling horribly.

I replaced it with a "Powerbond" by Dayco. Made in Australia. Smooth as silk for the past ~12k. I only went with this method because I didnt have the time to wait for one to come from the dealer. The material is some kind of graphene so the Dayco one was significantly lighter than OEM.

I would highly recommend OEM when it comes to this part. The construction and solid steel material is superior to anything aftermarket.

 

Absolutely use OEM, unless one of the aftermarket performance vendors steps up.

Fluidampr is having a look.

Also, Toyota employed the same harmonic balancer on LS series from 1990 - 2006.

When you increase compression and/or displacement, as in the LS 1UZ-FE/ 3UZ-FE evolution suggests the OEM use a balancer tuned for that engine...NOT the same balancer when 50-70 horsepower increase...






Same harmonic balancer for all of these engines.....
Anyone know how the superceding balancer P.N. compares to the original?

 

OEM is inferior, if you are serious use a SFI part that you take to a machine shop for perfect balance at minimum and if you can afford it use a fluid damper.

 

SFI is a standard?

Was unable to locate an off the shelf premium aftermarket damper such as Fluidampr for
1UZ-FE.

Numerous posts on LS400 and LS430 forums with vibration issues.

The harmonic balancer is often overlooked, if not outright ignored.

An OEM damper is about $300.

A premium aftermarket Fluidampr for a Chevy or Ford is closer to $450.

Large quantities of 1UZ-FE, 2UZ-FE and 3UZ-FE engines produced. (Anyone with statistics??)

An untapped market.

 

Yes SFI is a racing standard used to ensure that parts don't fail and have potential to hurt drivers/bystanders and are far far more durable than any stock type damper and do a far better job. I'm my surprised there isn't one for these cars since they are not raced and all, would be nice if someone at least cut Chevy ones to match the cranks since the fluid dampers have legitimately superior crank harmonics that dramatically lower bearing wear for ultra high power engines

 

Any idea how many hours this takes to replace at a decent mechanic? My LS is 20 years old and perhaps a Dayco will help?

 

One who knows what he is doing should not take more than two hours max. You will need to remove anything that prevents access to the crank from the front with an impact unless you use the red neck trick to get the bolt moving.

 

Avoid aftermarket stuff.

Use the correct harmonic balancer hub bolt removal/installation tool to avoid damaging it.

See:

https://www.clublexus.com/forums/ls-...ct-wrench.html

 

Just use an impact......

 

Thanks for this post. Hope it will solve my vibration issue on my 1990.

 

​To loosen the crankshaft bolt requires counterclockwise rotation (facing engine)

Is it recommended to turn the engine in that direction without holding the harmonic damper (1UZ-FE is internally balanced, so not a harmonic balancer used on externally balanced engines, but harmonic damper) in place without SST?

Thought I read somewhere VVTi and camshaft scissor gears may not respond well to reverse rotation.(Should the crankshaft rotate before bolt is loosened)

What is program then for holding harmonic balancer in place while tightening the crankshaft bolt to torque spec while preventing damage to the rubber damping ring??

Invest in the $60 tool and avoid damaging your engine or harmonic damper.

 

Impact. Nothing moves when you remove it. Nothing is damaged putting it back and you don't go to a spec you use red loctite or black RTV and impact it back on and stop after initial rotation resistance plus 1-1.5 seconds at 250 on an electric regulated gun. Way faster and I've done hundreds that way across nearly every engine out there.

You don't need a special tool for any of them except VW engines since they do not self index, if you have doubt just use the ISO spec for the thread and diameter of the crank bolt for the max TQ setting

 

Can you post the page from an LS400 Lexus Shop Manual containing these instructions?