Correct me if Im wrong.... Crank Pulley / Harmonic Balancer

[tnrknght]

I heard a while back that replacing your factory harmonic balancer with a lightweight underdrive pulley was unwise unless you replace your flywheel with a lightweight counterpart as well, otherwise youd throw off the balance of the motor. Does anyone have any feedback on the topic?

[anothernord]

Subarus do not have harmonic balancers, the crank pulley is just ... a pulley.

As far as the balance of the motor; it doesn't really affect anything to have different amounts of weight hanging off either end of the engine. Think about the force the pistons have on the crank bearings compared to a 30 lb flywheel just sitting there.

The only issue with running lightweight spinning things is that misfire codes sometimes pop up.

[chuckthefuk]

Oh great. Another harmonic balancer question/debate.

I had a very long debate with mike-tracy about this.

His argument was:
- the SAE technical papers on the Boxer motor states that it uses a harmonic balancer.
--> "A double mass harmonic balancer is adopted to disperse the torsional
and bending vibration up to the 7500 rpm of maximum operating speed."
--> http://www.surrealmirage.com/subaru/files/SAE_boxer.pdf
--> http://img.photobucket.com/albums/v201/ ... za/pg4.jpg
--> Based on EJ20G I believe
- ATI & fluidampr make crank damper that are Fluid filled or Elastomer


My argument:
- Not a damper, only a thin rubber strip to soften the effects of the the a/c clutch and other accesories connected to it.
- Short crankshaft.
- Balanced motor by design
- 100,000 Lightweight, underdrive, overdrive crank pulleys made with no one reporting engine failure.
---> I personally have these on a handful of various EJ-series motors with no issues 100,000+ km on all of them.
- Subaru of America (SoA) response below
---->
"Thank you for your patience as I checked with our Technical Services Department regarding your message below. They advised that the crank pulley is a pulley and nothing else. It is not used as a harmonic damper/balancer.

Thanks for the opportunity to be of assistance. If you need any future assistance, please feel free to contact us again."

Best wishes,

John J. Mergen
Customer Service Department
Subaru of America, Inc.
----


As anothernord explained having the LW flywheel and crank can throw a code but this is unrelated to vibration.

Blah... stupid topic with no real factual answers
-Chuck

[harrymaneuvers]

Well put.

I can also vouch for running a LW crank pulley with no adverse effects and I know TONS of other subaru owners who have them with no reported problems.

A word for the wise though... if you are putting it on a 4EAT subaru where the bellhousing plug is NOT easily accessible (just about every subaru I have seen besides my BD), then you are going to have a heck of a time holding the crank or pulley itself in place while you try to brake the crank bolt free and when you are trying to torque it back down.

On a 4EAT you need access to the plug so that you can put a large screwdriver or prybar in there to lock the flywheel in place. That then allows you to break the crank bolt loose and torque it when you are done.


If you dont have access to that plug (as was the case on the FXT), then the easiest way I found to "lock" the motor was to put 2 3/8 drive extensions (3-10 inches long) in the holes in the OEM pulley. Then I was able to place my huge prybar between the two extensions that are now sticking out of the pulley. Turn the motor until the prybar locks up against the bottom of the frame rail on the car. Then you can go nuts with removing the crank bolt or installing it.

The only reason why I didnt put a LW crank pulley on the FXT was that most of the aftermarket LW crank pulleys that I have seen dont retain those perfectly shaped holes that fit the 3/8 extensions and I didnt want to do what was needed to access the plug to lock the flywheel for installation.

[d1giPhux]

I agree with the others who have states that the crank pulley is NOT a harmonic balancer. In fact, I asked 2 subaru dealerships around here the same question, and they told me it was NOT a harmonic balancer. I've been running a lightweight crankpulley for ages and never had ANY trouble with my car. I also run a lightweight flywheel at the same time with no trouble.

[GTDrifter]

Well put.

I can also vouch for running a LW crank pulley with no adverse effects and I know TONS of other subaru owners who have them with no reported problems.

A word for the wise though... if you are putting it on a 4EAT subaru where the bellhousing plug is NOT easily accessible (just about every subaru I have seen besides my BD), then you are going to have a heck of a time holding the crank or pulley itself in place while you try to brake the crank bolt free and when you are trying to torque it back down.

On a 4EAT you need access to the plug so that you can put a large screwdriver or prybar in there to lock the flywheel in place. That then allows you to break the crank bolt loose and torque it when you are done.


If you dont have access to that plug (as was the case on the FXT), then the easiest way I found to "lock" the motor was to put 2 3/8 drive extensions (3-10 inches long) in the holes in the OEM pulley. Then I was able to place my huge prybar between the two extensions that are now sticking out of the pulley. Turn the motor until the prybar locks up against the bottom of the frame rail on the car. Then you can go nuts with removing the crank bolt or installing it.

The only reason why I didnt put a LW crank pulley on the FXT was that most of the aftermarket LW crank pulleys that I have seen dont retain those perfectly shaped holes that fit the 3/8 extensions and I didnt want to do what was needed to access the plug to lock the flywheel for installation.

you could wrap the belt (the one that goes around alternator, crank, and power steering pump) around the crank pulley, wrap around the alternator and fold the rest under the belt wrapping under the crank pulley. make sure it's in the direction where when the pulley turns it wraps the belt under even more. I suggest using an old belt for this but it works every time. I could snap a pic sunday if you wish

[tnrknght]

Okay, well I just got used to calling it a harmonic balancer because of my 3000gt.. so no 1000% evidence either way but it wont kill my motor? All I needed to hear. I know with the 3kgt they recommended replacing the harmonic balancer in relation to a lightweight flywheel.